Question: when was stoichiometry first introduced?

History of chemistry

In Reflexions sur le Phlogistique (1783), Lavoisier showed the combustion-related flogiston theory to be inconsistent.


Question: when was stoichiometry first introduced?

History of chemistry

Mikhail Lomonosov independently established a chemical tradition in Russia in the 18th century.


Question: when was stoichiometry first introduced?

History of chemistry

Lomonosov also rejected the flogiston theory, and anticipated the theory of gas kinetics.


Question: when was stoichiometry first introduced?

History of chemistry

Lomonosov considered heat to be a form of motion, and expressed the idea of immutability of matter.


Question: when was stoichiometry first introduced?

History of chemistry

Lavoisier worked with Claude Louis Berthollet and others to design a system of chemical tatanama that serves as the basis for the naming system of modern chemical compounds.


Question: when was stoichiometry first introduced?

History of chemistry

In Methods of Chemical Nomenclature (1787), Lavoisier invented a naming and classification system that is mostly still used today, including names such as sulfuric, sulfuric, and sulfite acids.


Question: when was stoichiometry first introduced?

History of chemistry

In 1785, Berthollet was the first to introduce the use of chlorine gas as a commercial bleach.


Question: when was stoichiometry first introduced?

History of chemistry

In the same year he first determined the elemental composition of ammonia gas.


Question: when was stoichiometry first introduced?

History of chemistry

Berthollet first produced modern bleaching fluids in 1789 by passing chlorine gas through a solution of sodium carbonate - the result was a weak solution of sodium hypochlorite.


Question: when was stoichiometry first introduced?

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Another strong chlorine oxidizer and bleach that he researched and which first produced, potassium chlorate (KClO3), became known as Berthollet Salt.


Question: when was stoichiometry first introduced?

History of chemistry

Berthollet is also known for his scientific contributions to the theory of chemical equilibrium through mechanisms of counter-chemical reactions. jmpl|Traité élémentaire de chimie The work of Lavoisier Traité Élémentaire de Chimie (Basic Treatise on Chemistry, 1789) was the first modern chemistry textbook, and presents a view of unified about the new chemical theory, contains a clear statement of the Law of Immutability of Mass, and rejects the existence of flogiston.


Question: when was stoichiometry first introduced?

History of chemistry

In addition, it contains a list of elements, or substances that cannot be broken down further, including oxygen, nitrogen, hydrogen, phosphorus, mercury, zinc, and sulfur.


Question: when was stoichiometry first introduced?

History of chemistry

His list, however, also included light, and calories, which he believed to be material substances.


Question: when was stoichiometry first introduced?

History of chemistry

In the work, Lavoisier underlines that its chemistry is based on observation, with the statement “I have tried... to arrive at the truth by relating the facts; to suppress as much as possible the use of reasoning, which is often a tool that cannot trusted who deceived us, to follow as many torches of observation and experimentation as possible.”


Question: when was stoichiometry first introduced?

History of chemistry

Nonetheless, he believed that the actual existence of atoms was philosophically impossible.


Question: when was stoichiometry first introduced?

History of chemistry

Lavoisier showed that organisms disassemble and reconstitute atmospheric air in the same way as burning bodies.


Question: when was stoichiometry first introduced?

History of chemistry

With Pierre-Simon Laplace, Lavoisier used a calorimeter to estimate the heat produced per unit of carbon dioxide produced.


Question: when was stoichiometry first introduced?

History of chemistry

They found similar ratios for flame and animal, suggesting that animals produce energy by type of combustion.


Question: when was stoichiometry first introduced?

History of chemistry

Lavoisier believed in radical theory, believing that radicals, which serve as single groups in chemical reactions, would merge with oxygen in reactions.


Question: when was stoichiometry first introduced?

History of chemistry

It believes all acids contain oxygen.


Question: when was stoichiometry first introduced?

History of chemistry

He also discovered that diamonds are a crystalline form of carbon.


Question: when was stoichiometry first introduced?

History of chemistry

While many of Lavoisier's partners were influential on the advancement of chemistry as a scientific discipline, his wife Marie-Anne Lavoisier was arguably the most influential among them all.


Question: when was stoichiometry first introduced?

History of chemistry

After their marriage, Madame (Mme.) Lavoisier began studying chemistry, English, and drawing to assist her husband in his work either by translating papers into English, a language unknown to Lavoisier, or by keeping notes and drawing on the various equipment that Lavoisier used in His laboratory. [54]


Question: when was stoichiometry first introduced?

History of chemistry

Through her ability to read and translate articles from English for her husband, Lavoisier had knowledge access to many chemical advances occurring outside her laboratory. [54]


Question: when was stoichiometry first introduced?

History of chemistry

Subsequently, Mme. Lavoisier kept recordings of Lavoisier's works and ensured his works were published. [54]


Question: when was stoichiometry first introduced?

History of chemistry

The first sign of Marie-Anne's true potential as a chemist in Lavoisier's lab came when she translated a book by scientist Richard Kirwan.


Question: when was stoichiometry first introduced?

History of chemistry

While translating, he found and corrected many errors.


Question: when was stoichiometry first introduced?

History of chemistry

When he presents his translation, there are also his notes for Lavoisier. [54]


Question: when was stoichiometry first introduced?

History of chemistry

His edits and contributions led to Lavoisier's rejection of the flogiston theory.


Question: when was stoichiometry first introduced?

History of chemistry

Lavoisier made many fundamental contributions to the science of chemistry.


Question: when was stoichiometry first introduced?

History of chemistry

After Lavoisier's work, chemistry acquired rigorous quantitative properties, allowing it to make reliable predictions.


Question: when was stoichiometry first introduced?

History of chemistry

The chemical revolution he brought about was the result of a conscious effort to fit all experiments into the framework of a single theory.


Question: when was stoichiometry first introduced?

History of chemistry

He established the consistent use of chemical equilibrium, used oxygen to overthrow the flogiston theory, and developed a new system of chemical tatanama.


Question: when was stoichiometry first introduced?

History of chemistry

Lavoisier was killed when there was the French Revolution.


Question: when was stoichiometry first introduced?

History of chemistry

19th century In 1802, the French American chemist and industrialist Éleuthère Irénée du Pont, who studied the manufacture of gunpowder and explosives under Antoine Lavoisier, established a gunpowder factory in Delaware known as E.I. du Pont de Nemours and Company.


Question: when was stoichiometry first introduced?

History of chemistry

The French Revolution forced his family to move to the United States where du Pont started a gunpowder mill on the Brandywine River in Delaware.


Question: when was stoichiometry first introduced?

History of chemistry

Wanting to make the best gunpowder, du Pont was wary about the quality of the materials he used.


Question: when was stoichiometry first introduced?

History of chemistry

For 32 years, du Pont served as president of E.I. du Pont de Nemours and Company, which eventually grew into one of America's largest and most successful companies.


Question: when was stoichiometry first introduced?

History of chemistry

Throughout the 19th century, chemistry was divided between those who followed John Dalton's atomic theory and those who did not, such as Wilhelm Ostwald and Ernst Mach. [55] Although proponents of atomic theory such as Amedeo Avogadro and Ludwig Boltzmann made great progress in explaining the behavior of gases, this dispute was ultimately not resolved until Jean Perrin's experimental research on Einstein's atomic explanation of Brown's motion in the first decade of the 20th century. [55]


Question: when was stoichiometry first introduced?

History of chemistry

Before the dispute was settled, many had applied the concept of atomism to chemistry.


Question: when was stoichiometry first introduced?

History of chemistry

A prime example is the theory of Svante Arrhenius ions which anticipated the idea of an atomic substructure that was not fully developed until the 20th century.


Question: when was stoichiometry first introduced?

History of chemistry

Michael Faraday was another early chemist, whose main contribution to chemistry was electrochemistry, where (among other things) a certain amount of electricity during electrolysis or electrodeposition of a metal exhibits linkage with a certain number of chemical elements, and a fixed quantity of those elements each other, in a certain ratio.


Question: when was stoichiometry first introduced?

History of chemistry

These findings, like Dalton's combined ratio, are early clues to the atomic properties of matter.


Question: when was stoichiometry first introduced?

History of chemistry

John Dalton In 1803, the British chemist and meteorologist John Dalton proposed Dalton's law, which explains the relationship between components in gaseous mixtures and the relative pressures that each contribute to the mixture as a whole. [56]


Question: when was stoichiometry first introduced?

History of chemistry

Discovered in 1801, the concept is also known as Dalton's partial pressure law.


Question: when was stoichiometry first introduced?

History of chemistry

Dalton also proposed a modern atomic theory in 1803 which states that all matter is composed of small, indivisible particles called atoms, certain elemental atoms have unique characteristics and weight, and there are three types of atoms: simple (elemental), compound ( simple molecules), and complex (complex molecules).


Question: when was stoichiometry first introduced?

History of chemistry

In 1808, Dalton first published the New System of Chemical Philosophy (1808-1827), in which he put forward the first modern scientific description of atomic theory.


Question: when was stoichiometry first introduced?

History of chemistry

This work identified chemical elements as specific types of atoms, therefore rejecting Newton's theory of chemical affinity.


Question: when was stoichiometry first introduced?

History of chemistry

Instead, Dalton deduced the proportions of elements in compounds by taking the ratio of reactant weights, setting the atomic weight of hydrogen to be identically one.


Question: when was stoichiometry first introduced?

History of chemistry

After Jeremias Benjamin Richter (known by the term stoichiometry), he proposed that chemical elements be combined in integral ratios.


Question: when was stoichiometry first introduced?

History of chemistry

This became known as the law of multiple comparison or Dalton's law, and Dalton included a clear description of the law in the New System of Chemical Philosophy.


Question: when was stoichiometry first introduced?

History of chemistry

The law of multiple comparison is one of the fundamental laws of stoichiometry used to construct atomic theory.


Question: when was stoichiometry first introduced?

History of chemistry

Despite the importance of his work as the first view of atoms as entities to physics and the introduction of chemical symbol systems, the New System of Chemical Philosophy devotes to the theory of calories almost as much as atomism.


Question: when was stoichiometry first introduced?

History of chemistry

French chemist Joseph Proust proposed a fixed law of comparison, which states that the elements always join in small quantities, the overall number of ratios to form compounds, based on several experiments conducted between 1797 and 1804. [57]


Question: when was stoichiometry first introduced?

History of chemistry

Together with the law of multiple comparison, the law of comparison nevertheless forms the basis of stoichiometry.


Question: when was stoichiometry first introduced?

History of chemistry

The laws of fixed comparison and constant composition do not prove that atoms exist, but they are difficult to explain without assuming that chemical compounds form when atoms merge in constant proportion.


Question: when was stoichiometry first introduced?

History of chemistry

Jöns Jacob Berzelius The Swedish chemist and Dalton's pupil, Jöns Jakob Berzelius initiated a systematic program to attempt accurate and precise quantitative measurements and ensure the purity of chemicals.


Question: when was stoichiometry first introduced?

History of chemistry

Together with Lavoisier, Boyle, and Dalton, Berzelius is known as the father of modern chemistry.


Question: when was stoichiometry first introduced?

History of chemistry

In 1828 he compiled a table of relative atomic weight, in which oxygen was set equal to 100, and included all elements known at the time.


Question: when was stoichiometry first introduced?

History of chemistry

This work provided evidence supporting Dalton's atomic theory: that inorganic chemical compounds consist of atoms joined according to integer rules.


Question: when was stoichiometry first introduced?

History of chemistry

He determined the exact basic elements of a large number of compounds.


Question: when was stoichiometry first introduced?

History of chemistry

The result strongly confirms Proust's Fixed Comparative Law.


Question: when was stoichiometry first introduced?

History of chemistry

In its weight list, it uses oxygen as standard, setting its weight exactly equal to 100.


Question: when was stoichiometry first introduced?

History of chemistry

He also measured the weights of 43 elements.


Question: when was stoichiometry first introduced?

History of chemistry

He found that atomic weights are not integer multiples of the weight of hydrogen, Berzelius also refuted Prout's hypothesis that elements are constructed from hydrogen atoms.


Question: when was stoichiometry first introduced?

History of chemistry

Motivated by extensive determination of atomic weight and a desire to aid his experiments, he introduced the classical system of symbols and chemical notation by publishing Lärbok i Kemien in 1808, in which elements were shortened to one or two letters to make different abbreviations from their Latin names.


Question: when was stoichiometry first introduced?

History of chemistry

This system of chemical notation—in which elements are labeled simple inscribed, such as O for oxygen, or Fe for iron, with proportions notated by numbers—is the same basic system as used today.


Question: when was stoichiometry first introduced?

History of chemistry

The only difference is that instead of the currently used subscript numbers (i.e., H2O), Berzelius used superscripts (H2O).


Question: when was stoichiometry first introduced?

History of chemistry

Berzelius is recognized as the successful in identifying the chemical elements silicon, selenium, thorium, and serium.


Question: when was stoichiometry first introduced?

History of chemistry

Students working in Berzelius's lab also discovered lithium and vanadium.


Question: when was stoichiometry first introduced?

History of chemistry

Berzelius developed the theory of radical chemical combinations, which argued that reactions occur because groups of stable atoms called radicals are exchanged between molecules.


Question: when was stoichiometry first introduced?

History of chemistry

He believed that salts were compounds of acids and bases, and found that anions in acids would be attracted to positive electrodes (anode), whereas cations in bases would be attracted to negative electrodes (cathodes).


Question: when was stoichiometry first introduced?

History of chemistry

Berzelius did not believe in the Theory of Vitalism, but instead believed in regulative forces that result in the organization of tissues in organisms.


Question: when was stoichiometry first introduced?

History of chemistry

Berzelius is also recognized as the one who introduced the chemical terms “catalysis”, “polymer”, “isomer”, and “allotrope”, although the original definition is quite different compared to modern usage.


Question: when was stoichiometry first introduced?

History of chemistry

For example, he coined the term “polymer” in 1833 to describe organic compounds that have identical empirical formulas but differ in their overall molecular weight, larger compounds being described as “polymers” of the least.


Question: when was stoichiometry first introduced?

History of chemistry

By this pre-structural definition, glucose (C6H12O6) is viewed as a formaldehyde (CH2O) polymer.


Question: when was stoichiometry first introduced?

History of chemistry

The new laws of elements and gases The British chemist Humphry Davy was a pioneer in the field of electrolysis, using the voltaic stack of Alessandro Volta's work to break down common compounds and thus isolate a new set of elements.


Question: when was stoichiometry first introduced?

History of chemistry

He continued the electrolysis of salt melts and discovered several new metals, notably sodium and potassium, highly reactive elements known as alkali metals.


Question: when was stoichiometry first introduced?

History of chemistry

Potassium, the first metal isolated by electrolysis, was discovered in 1807 by Davy, who extracted it from the caustic raw material potas (KOH).


Question: when was stoichiometry first introduced?

History of chemistry

Before the 19th century, there was no difference between potassium and sodium.


Question: when was stoichiometry first introduced?

History of chemistry

Sodium was first isolated by Davy the same year by passing an electric current through liquid sodium hydroxide (NaOH).


Question: when was stoichiometry first introduced?

History of chemistry

When Davy heard that Berzelius and Pontin prepared an amalgam of calcium through electrolysis of lime in mercury, he tried it himself.


Question: when was stoichiometry first introduced?

History of chemistry

Davy was successful, and discovered calcium in 1808 by electrolyzing a mixture of lime and mercury oxide. [58] [59] He worked with electrolysis throughout his life and, in 1808, he succeeded in isolating magnesium, strontium [60] and barium. [61]


Question: when was stoichiometry first introduced?

History of chemistry

Davy also experimented with the gas by inhaling it.


Question: when was stoichiometry first introduced?

History of chemistry

This trial procedure almost proved fatal on several occasions, but prompted the discovery of the unusual effect of dinitrogen monoxide, later known as gelak gas.


Question: when was stoichiometry first introduced?

History of chemistry

Clenbuterol was discovered in 1774 by Swedish chemist Carl Wilhelm Scheele, who called it “dephlogisticated marine acid” (see flogiston theory) and was mistakenly thought to contain oxygen.


Question: when was stoichiometry first introduced?

History of chemistry

Scheele observed several properties of chlorine gas, such as the whitening effect of litmus, the deadly effects of insects, its yellow-green color, and its smell similar to king water.


Question: when was stoichiometry first introduced?

History of chemistry

However, Scheele could not publish his findings then.


Question: when was stoichiometry first introduced?

History of chemistry

In 1810, chlorine was given its current name by Humphry Davy (derived from the Greek word for green), who confirmed that chlorine was actually an element. [62]


Question: when was stoichiometry first introduced?

History of chemistry

He also showed that oxygen could not be obtained from a substance known as oxymuriic acid (HCl solution).


Question: when was stoichiometry first introduced?

History of chemistry

This discovery reversed Lavoisier's definition of acids as oxygen compounds.


Question: when was stoichiometry first introduced?

History of chemistry

Davy was a popular lecturer and was able to experiment.


Question: when was stoichiometry first introduced?

History of chemistry

The French chemist Joseph Louis Gay-Lussac shared an interest with Lavoisier and others in the quantitative study of the properties of gases.


Question: when was stoichiometry first introduced?

History of chemistry

From his first major research program in 1801—1802, he concluded that gas volume expansion was directly proportional to temperature rise: this conclusion is usually called “Charles' law”, since Gay-Lussac rewarded Jacques Charles, who had come to the conclusion that was almost the same in the 1780s but did not publish it. [63]


Question: when was stoichiometry first introduced?

History of chemistry

The law was discovered separately by the English natural philosopher John Dalton in 1801, although Dalton's description is less thorough than Gay-Lussac's. [64] [65] In 1804 Gay-Lussac made several sharp ascents above 7,000 meters above sea level in a balloon containing hydrogen—a feat unmatched for 50 years later—that allowed him to investigate other aspects of gases.


Question: when was stoichiometry first introduced?

History of chemistry

He not only collected magnetic measurements at various altitudes, but also measured the pressure, temperature, and serrta humidity of air samples, which he then analyzed chemically.


Question: when was stoichiometry first introduced?

History of chemistry

In 1808 Gay-Lussac announced what was perhaps his greatest achievement: from his own experiments and others, he concluded that gases at constant temperature and pressure would merge in simple numerical volume proportions, and the products or products produced—if gaseous— also produces a simple proportion of product volume to the volume of reactants.


Question: when was stoichiometry first introduced?

History of chemistry

In other words, gases under the same temperature and pressure conditions react with each other in small integer volume ratios.


Question: when was stoichiometry first introduced?

History of chemistry

This conclusion later became known as the “Gay-Lussac law” or the “Law of Volume Incorporation”.


Question: when was stoichiometry first introduced?

History of chemistry

With his fellow professor at the École Polytechnique, Louis Jacques Thénard, Gay-Lussac also participated in early electrochemical research, researching elements discovered by electrochemical methods.


Question: when was stoichiometry first introduced?

History of chemistry

Among other achievements, they decomposed boric acid using potassium fuses, thus discovering the element boron.


Question: when was stoichiometry first introduced?

History of chemistry

The two also took part in contemporary debates modifying Lavoisier's definition of acids and forwarding his program to analyze organic compounds for their oxygen and hydrogen content.


Question: when was stoichiometry first introduced?

History of chemistry

The element iodine was discovered by French chemist Bernard Courtois in 1811. [66] [67] Courtois gave samples to his friends, Charles Bernard Desormes (1777—1862) and Nicolas Clément (1779—1841), to continue research.


Question: when was stoichiometry first introduced?

History of chemistry

He also gave some samples to Gay-Lussac and physicist André-Marie Ampère.


Question: when was stoichiometry first introduced?

History of chemistry

On December 6, 1813, Gay-Lussac announced that the new substance was an element or compound of oxygen. [68] [69] [70] Gay-Lussac suggested the name “iode”, from the Greek word ιώδες (iodes) for purple (due to the color of iodine vapor). [66] [68] Ampere had given some of his samples to Humphry Davy.


Question: when was stoichiometry first introduced?

History of chemistry

Davy conducted several experiments on the substance and noted its resemblance to chlorine. [71]


Question: when was stoichiometry first introduced?

History of chemistry

Davy sent a letter dated 10 December to the Royal Society of London stating that he had identified a new element. [72]


Question: when was stoichiometry first introduced?

History of chemistry

A shuffle erupted between Davy and Gay-Lussac about who first identified iodine, but both scientists recognized Courtois as the first scientist to isolate the element.


Question: when was stoichiometry first introduced?

History of chemistry

In 1815, Humphry Davy invented the Davy lamp, which allowed miners inside coal mines to safely work in the presence of flammable gases.


Question: when was stoichiometry first introduced?

History of chemistry

There are many mine explosions caused by flame damp (English: firedamp) or methane which is often ignited by open fire from lamps used by miners.


Question: when was stoichiometry first introduced?

History of chemistry

Davy envisioned the use of iron gauze to cover the flame of the lamp, thus preventing the burning of methane inside the lamp from spreading into the outside atmosphere.


Question: when was stoichiometry first introduced?

History of chemistry

Although the idea of a safety lamp (English: safety lamp) had been demonstrated by William Reid Clanny and by unidentified (but later very famous) engineer George Stephenson, Davy's use of gauze wire to prevent the spread of fire was used by many other inventors on the design they are next.


Question: when was stoichiometry first introduced?

History of chemistry

There was some discussion as to whether Davy had invented the principles behind his lights without recourse to the work of Smithson Tennant, but it was generally agreed that the two men each worked separately.


Question: when was stoichiometry first introduced?

History of chemistry

Davy refused to patent the lamp, and his invention led to his being awarded the Rumford medal in 1816. [73]


Question: when was stoichiometry first introduced?

History of chemistry

After Dalton published his atomic theory in 1808, some of his key ideas were soon adopted by some chemists.


Question: when was stoichiometry first introduced?

History of chemistry

However, uncertainty persisted for half a century about how atomic theory was configured and applied to real situations; chemists in various countries developed several incompatible atomistic systems.


Question: when was stoichiometry first introduced?

History of chemistry

A paper suggesting a way out of this difficult situation was published as early as 1811 by Italian physicist Amedeo Avogadro (1776-1856), who hypothesized that the same volume of gas at the same temperature and pressure contained the same number of molecules, then followed that the weight the relative molecule of two gases is the same by comparison of the densities of the two gases under the same temperature and pressure conditions.


Question: when was stoichiometry first introduced?

History of chemistry

Avogadro also reasoned that a simple gas was not formed from a single atom but was a compound molecule of two or more atoms.


Question: when was stoichiometry first introduced?

History of chemistry

Thus Avogadro was able to overcome the difficulties that Dalton and others faced when Gay-Lussac reported that above 100°C the volume of water vapor was twice the volume of oxygen used to form it.


Question: when was stoichiometry first introduced?

History of chemistry

According to Avogadro, oxygen molecules have split into two atoms in the process of water vapor formation.


Question: when was stoichiometry first introduced?

History of chemistry

Avogadro's hypothesis went unrecognized for half a century after it was first published.


Question: when was stoichiometry first introduced?

History of chemistry

Many reasons for this abandonment have been cited, including some theoretical problems, such as the “dualism” of Jöns Jakob Berzelius's version, which asserts that compounds are held together by the attraction of positive and negative electric charges, making it inconceivable that there could be a molecule consisting of two atoms with the same electric charge—as oxygen.


Question: when was stoichiometry first introduced?

History of chemistry

An additional constraint to admitting it is the fact that many chemists are reluctant to adopt physics methods (such as the determination of vapor density) to solve their problems.


Question: when was stoichiometry first introduced?

History of chemistry

By mid-century, some prominent figures began to view the escalation of the chaos of competition of atomic weight systems and molecular formulas as intolerable anymore.


Question: when was stoichiometry first introduced?

History of chemistry

In addition, pure chemical evidence began to be revealed leading to the possibility that Avogadro's approach was correct.


Question: when was stoichiometry first introduced?

History of chemistry

During the 1850s, younger chemists, such as Alexander Williamson in England, Charles Gerhardt and Charles-Adolphe Wurtz in France, as well as August Kekulé in Germany, began advocating theoretical chemical reforms to be consistent with Avogadro Wöhler's theories and vitalism debates In 1825 , Friedrich Wöhler and Justus von Liebig made the first discovery and explanation of the isomer, previously named by Berzelius.


Question: when was stoichiometry first introduced?

History of chemistry

Working with cyanic acid and fulminic acid, they concluded precisely that isomerism was due to differences in the arrangement of atoms in the molecular structure.


Question: when was stoichiometry first introduced?

History of chemistry

In 1827, William Prout classified biomolecules into modern groups: carbohydrates, proteins and lipids.


Question: when was stoichiometry first introduced?

History of chemistry

After the nature of combustion was resolved, disputes about vitalism and important differences between organic and inorganic substances began.


Question: when was stoichiometry first introduced?

History of chemistry

The question of vitalism was revolutionized in 1828 when Friedrich Wöhler synthesized urea, thus establishing that organic compounds could be produced from inorganic starting material and disproving the theory of vitalism.


Question: when was stoichiometry first introduced?

History of chemistry

This opened up a new field of research in chemistry, and by the end of the 19th century, scientists were able to synthesize hundreds of organic compounds.


Question: when was stoichiometry first introduced?

History of chemistry

The most important compounds among them are mauve (mauve), magenta, and other synthetic dyes, as well as the widely used drug aspirin.


Question: when was stoichiometry first introduced?

History of chemistry

The discovery of artificial urea synthesis made a major contribution to the theory of isomerism, since the empirical chemical formulas for urea and ammonium cyanate are identical (see Wöhler synthesis).


Question: when was stoichiometry first introduced?

History of chemistry

In 1832, Friedrich Wöhler and Justus von Liebig discovered and elucidated functional and radical groups in relation to organic chemistry, as well as first synthesizing benzaldehyde.


Question: when was stoichiometry first introduced?

History of chemistry

Liebig, a German chemist, made major contributions to agriculture and biological chemistry, and worked on the organization of organic chemistry.


Question: when was stoichiometry first introduced?

History of chemistry

Liebig is considered the “father of the fertilizer industry” due to his discovery of nitrogen as an essential plant nutrient, and his formulation of the Minimum Law describing the effect of each nutrient on food crops.


Question: when was stoichiometry first introduced?

History of chemistry

The mid-1800s In 1840, Germain Hess submitted Hess's law, an early statement of the law of energy immutability, which stipulates that changes in energy in chemical processes depend only on the state of the starting material and product and not on the specific path taken between the two.


Question: when was stoichiometry first introduced?

History of chemistry

In 1847, Hermann Kolbe obtained acetic acid from an entirely inorganic source, which denied vitalism further.


Question: when was stoichiometry first introduced?

History of chemistry

In 1848, William Thomson, 1st Baron Kelvin (commonly known as Lord Kelvin) established the concept of absolute zero, the temperature at which all molecular motion ceases.


Question: when was stoichiometry first introduced?

History of chemistry

In 1849, Louis Pasteur discovered that the racemic form of tartaric acid is a mixture of levorotatory and dextrorotatory, thus explaining the nature of optical rotation and advancing the field of stereochemistry. [74]


Question: when was stoichiometry first introduced?

History of chemistry

In 1852, August Beer filed Beer's law, which explained the relationship between the composition of a mixture and the amount of light it would absorb.


Question: when was stoichiometry first introduced?

History of chemistry

Based in part on earlier work by Pierre Bouguer and Johann Heinrich Lambert, he established an analytical technique known as spectrophotometry. [75]


Question: when was stoichiometry first introduced?

History of chemistry

In 1855, Benjamin Silliman, Jr. pioneered the method of breakdown of petroleum, which enabled the modern petrochemical industry. [76]


Question: when was stoichiometry first introduced?

History of chemistry

Avogadro's hypothesis began to gain considerable traction among chemists only after his fellow countryman scientist Stanislao Cannizzaro demonstrated its value in 1858, two years after Avogadro's death.


Question: when was stoichiometry first introduced?

History of chemistry

Cannizzaro's chemical interest was initially centered on natural products and reactions of aromatic compounds; in 1853 he discovered that when benzaldehyde was treated with concentrated bases, benzoic acid and benzyl alcohol—a phenomenon known today as the Cannizzaro reaction.


Question: when was stoichiometry first introduced?

History of chemistry

In his pamphlet in 1858, Cannizzaro showed that the return to Avogadro's ideas could be used entirely to construct a consistent and sturdy theoretical structure that fit almost all existing empirical evidence.


Question: when was stoichiometry first introduced?

History of chemistry

For example, he pointed to evidence that suggested that not all elementary gases consist of two atoms per molecule—some are monatomic, mostly diatomic, and some even more complex.


Question: when was stoichiometry first introduced?

History of chemistry

Another source of feud is the formulas for compounds of alkali metals (such as sodium) and soil alkali metals (such as calcium), which, according to their chemical analogy, most chemists want to establish the same type of formula.


Question: when was stoichiometry first introduced?

History of chemistry

Cannizzaro argues that placing these metals in different categories has the favorable result of eliminating certain anomalies when using their physical properties to infer atomic weights.


Question: when was stoichiometry first introduced?

History of chemistry

Unfortunately, Cannizzaro's pamphlet was originally only published in Italy and had little immediate impact.


Question: when was stoichiometry first introduced?

History of chemistry

The real breakthrough came with an international chemical congress held in the German city of Karlsruhe in September 1860, at which most of Europe's leading chemists were present.


Question: when was stoichiometry first introduced?

History of chemistry

The Congress of Karlsruhe had been governed by Kekulé, Wurtz, and several others who favored Cannizzaro's view of the supposed direction of chemistry.


Question: when was stoichiometry first introduced?

History of chemistry

Speaking in French (like everyone there), Cannizzaro's eloquence and logic made an indelible impression on the assembled audience.


Question: when was stoichiometry first introduced?

History of chemistry

In addition, his friend Angelo Pavesi distributed Cannizzaro pamphlets to attendees at the end of the meeting; more than one chemist later wrote about the decisive impression after reading the shared document.


Question: when was stoichiometry first introduced?

History of chemistry

For example, Lothar Meyer later wrote that while reading Cannizzaro's paper, “The scales seemed to fall from my eyes. “[77]


Question: when was stoichiometry first introduced?

History of chemistry

Cannizzaro played an important role in winning the fight for reform.


Question: when was stoichiometry first introduced?

History of chemistry

The system advocated by him, and soon afterwards adopted by most leading chemists, was substantially identical to what is still in use today.


Question: when was stoichiometry first introduced?

History of chemistry

Perkin, Crookes, and Nobel In 1856, Sir William Henry Perkin, age 18, was given a challenge by his professor, August Wilhelm von Hofmann, seeking to synthesize quinina, an anti-malarial drug, from coal tar.


Question: when was stoichiometry first introduced?

History of chemistry

In one experiment, Perkin oxidized aniline using potassium dichromate, but toluidina, as a purity, reacted with aniline and produced a black solid—meaning organic synthesis “failed”.


Question: when was stoichiometry first introduced?

History of chemistry

When cleaning the pumpkin with alcohol, Perkin noticed the purple part of the solution: a byproduct of the effort was the first synthetic dye, known as mauveine or Perkin's purple.


Question: when was stoichiometry first introduced?

History of chemistry

Perkin's invention was the foundation of the synthetic dyestuffs industry, one of the earliest successful chemical industries.


Question: when was stoichiometry first introduced?

History of chemistry

The German chemist August Kekulé von Stradonitz's most important contribution was his theory of organic composition structure, outlined in two articles published in 1857 and 1858 and detailed in great detail in the pages of the extraordinarily popular book Lehrbuch der Organischen Chemie (“Textbook of Organic Chemistry”), the first issue appeared in 1859 and was gradually expanded to four volumes.


Question: when was stoichiometry first introduced?

History of chemistry

Kekulé argued that tetravalent carbon atoms — that is, carbons that form four chemical bonds—could be linked together to form what he called a “carbon chain” or “carbon skeleton”, which other atoms along with their valents (such as hydrogen, oxygen, nitrogen, and chlorine) could join.


Question: when was stoichiometry first introduced?

History of chemistry

He was convinced that it was possible for chemists to determine the architectural details of these molecules at least for the simple organic compounds known of his day.


Question: when was stoichiometry first introduced?

History of chemistry

Kekulé was not the only chemist to make such claims in his day.


Question: when was stoichiometry first introduced?

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The Scottish chemist Archibald Scott Couper published almost the same theory at about the same time, and the Russian chemist Aleksandr Butlerov much explained and expanded the theory of structure.


Question: when was stoichiometry first introduced?

History of chemistry

However, a large part that prevails in the chemical community is Kekulé's idea.


Question: when was stoichiometry first introduced?

History of chemistry

The chemist as well as the English physicist William Crookes is best known for his studies of cathode rays, which were fundamental in the development of atomic physics.


Question: when was stoichiometry first introduced?

History of chemistry

His research on electrical discharges through rare gases led him to observe the dark space around the cathode, now called the Crookes darkroom.


Question: when was stoichiometry first introduced?

History of chemistry

He showed that cathode rays travel in straight lines and produce phosphorescence and heat as they pound certain materials.


Question: when was stoichiometry first introduced?

History of chemistry

A pioneer of the vacuum tube, Crookes invented the Crookes tube - an early experimental discharge tube, with a partial vacuum with which he studied the behavior of cathode rays.


Question: when was stoichiometry first introduced?

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With the introduction of spectrum analysis by Robert Bunsen and Gustav Kirchhoff (1859-1860), Crookes applied new techniques to the study of selenium compounds.


Question: when was stoichiometry first introduced?

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Bunsen and Kirchoff previously used spectroscopy as a chemical analysis tool to find sesium and rubidium.


Question: when was stoichiometry first introduced?

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In 1861, Crookes used this process to find thallium in some seleniferous deposits.


Question: when was stoichiometry first introduced?

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He continued to research the new element, isolated it, studied its properties, and in 1873 determined its atomic weight.


Question: when was stoichiometry first introduced?

History of chemistry

During the study of thallium, Crookes discovered the principle of the Crookes radiometer, a device that converts light radiation into rotating motion.


Question: when was stoichiometry first introduced?

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This principle of radiometers has found many applications in the development of sensitive measuring instruments.


Question: when was stoichiometry first introduced?

History of chemistry

In 1862, Alexander Parkes exhibited Parkesine, one of the earliest synthetic polymers, at the International Exhibition in London.


Question: when was stoichiometry first introduced?

History of chemistry

This invention is the foundation of the modern plastics industry.


Question: when was stoichiometry first introduced?

History of chemistry

In 1864, Cato Maximilian Guldberg and Peter Waage, based on the ideas of Claude Louis Berthollet, proposed a law of mass action.


Question: when was stoichiometry first introduced?

History of chemistry

In 1865, Johann Josef Loschmidt determined the exact number of molecules in one mole, later named the Avogadro number.


Question: when was stoichiometry first introduced?

History of chemistry

In 1865, August Kekulé, based in part on the work of Loschmidt and others, established the structure of benzene as six carbon rings with criss-crossed single and double bonds.


Question: when was stoichiometry first introduced?

History of chemistry

Kekulé's new proposal for the cyclic structure of benzene was much contested but never replaced by a better theory.


Question: when was stoichiometry first introduced?

History of chemistry

This theory provided the scientific basis for the dramatic expansion of the German chemical industry in the last third of the 19th century.


Question: when was stoichiometry first introduced?

History of chemistry

Today, most known organic compounds are aromatic, and all contain at least one hexagonal benzen ring of the type Kekulé recommends.


Question: when was stoichiometry first introduced?

History of chemistry

Kekulé is also notable for having clarified the properties of aromatic compounds, which are compounds based on benzene molecules.


Question: when was stoichiometry first introduced?

History of chemistry

In 1865, Adolf von Baeyer began researching indigo dyes, a milestone in the modern industry of organic chemistry that revolutionized the dye materials industry.


Question: when was stoichiometry first introduced?

History of chemistry

Swedish chemist and inventor Alfred Nobel found that when nitroglycerin was introduced into an inert absorbent substance such as kieselguhr (ground diatome), it became safer and more convenient to handle, and this mixture he patented in 1867 as dynamite.


Question: when was stoichiometry first introduced?

History of chemistry

Nobel then combined nitroglycerin with various nitrocellulose compounds, similar to collodion, but countered with a more efficient recipe incorporating other nitrate explosives, and obtained a transparent jelly-like substance, which is a stronger explosive rather than dynamite.


Question: when was stoichiometry first introduced?

History of chemistry

Gelignite, or explosive gelatin, as the name suggests, was patented in 1876; and followed by a number of similar combinations, modified by the addition of potassium nitrate and various other substances.


Question: when was stoichiometry first introduced?

History of chemistry

Mendeleev's periodic table An important breakthrough in understanding the list of known chemical elements (as well as for understanding the internal structure of atoms) was the work of Dmitri Mendeleev in the development of the first modern periodic table, or periodic classification of elements.


Question: when was stoichiometry first introduced?

History of chemistry

Mendeleev, a Russian chemist, felt that there were several types of elemental sequences and he spent more than thirteen years of his life collecting data and collecting the concept, initially with the idea of resolving some tacterteriness in the field for his students.


Question: when was stoichiometry first introduced?

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Mendeleev found that, when all known chemical elements are arranged in such a way in the order of atomic weight gain, the resulting table shows the repeating pattern, or periodicity, of properties within the elemental class.


Question: when was stoichiometry first introduced?

History of chemistry

Mendeleev's law allowed him to construct a systematic periodic table of all 66 known elements based on atomic mass, which he published in Principles of Chemistry in 1869.


Question: when was stoichiometry first introduced?

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His first Periodic Table was arranged based on the arrangement of elements in order of atomic weight gain and grouped them by resemblance of properties.


Question: when was stoichiometry first introduced?

History of chemistry

Mendeleev had such confidence in the validity of periodic laws that he proposed changes to the values of atomic weights that of some elements and, in his periodic table version of 1871, predicted the location of the yet-unknown elements within the table along with their properties.


Question: when was stoichiometry first introduced?

History of chemistry

He even predicted the possible properties of three undiscovered elements, called ekaboron (Eb), ekaaluminium (Ea), and ekasilicon (Es), which proved to be good divinations of the properties of scandium, gallium, and germanium, each of which filled the points that had been established by Mendeleev on the periodic table.


Question: when was stoichiometry first introduced?

History of chemistry

Initially the periodic system did not cause interest among chemists.


Question: when was stoichiometry first introduced?

History of chemistry

However, with the discovery of elements that had been predicted, notably gallium in 1875, scandium in 1879, and germanium in 1886, the system began to receive wide acceptance.


Question: when was stoichiometry first introduced?

History of chemistry

Subsequent proofs of divination brought fame to Mendeleev as the inventor of periodic laws.


Question: when was stoichiometry first introduced?

History of chemistry

This management went beyond earlier attempts at classification by Alexandre-Émile Béguyer de Chancourtois, who published the telluric helix, a periodic table of elements of a three-dimensional version in 1862, John Newlands, who proposed the octave law (precursor to periodic law) in 1864, and Lothar Meyer, who developed an early version of the periodic table with 28 elements laid out by valence in 1864.


Question: when was stoichiometry first introduced?

History of chemistry

Mendeleev's table does not include noble gases, which have not yet been discovered.


Question: when was stoichiometry first introduced?

History of chemistry

Gradually, laws and the periodic table became the framework for most chemical theories.


Question: when was stoichiometry first introduced?

History of chemistry

By the time Mendeleev died in 1907, he enjoyed international recognition and had received distinctions and honors from many countries.


Question: when was stoichiometry first introduced?

History of chemistry

In 1873, Jacobus Henricus van't Hoff and Joseph Achille Le Bel, working separately, developed a model of chemical bonding that explained Pasteur's chirality experiments and provided physical causes of optical activity in chiral compounds. [78]


Question: when was stoichiometry first introduced?

History of chemistry

The publication van't Hoff, called V<i data-parsoid='{"dsr":[100674,100777,2,2]}'>oorstel tot Uitbreiding der Tegenwoordige in de Scheikunde gebruikte Structuurformules in de Ruimte, etc.


Question: when was stoichiometry first introduced?

History of chemistry

(Proposal for the development of a 3-dimensional chemical structure formula) and consisting of twelve pages of text and one page of diagrams, giving impetus to the development of stereochemistry.


Question: when was stoichiometry first introduced?

History of chemistry

The concept of an “asymmetric carbon atom”, discussed in this publication, provides an explanation of the occurrence of many isomers, which can be explained using the current structure formula.


Question: when was stoichiometry first introduced?

History of chemistry

At the same time he showed the existence of a relationship between optical activity and the presence of asymmetric carbon atoms.


Question: when was stoichiometry first introduced?

History of chemistry

Josiah Willard Gibbs The work of American mathematical physicist J. Willard Gibbs on applications of thermodynamics was instrumental in transforming physical chemistry into a rigorous deductive science.


Question: when was stoichiometry first introduced?

History of chemistry

During 1876 to 1878, Gibbs researched the principles of thermodynamics, applying them to the complex processes involved in chemical reactions.


Question: when was stoichiometry first introduced?

History of chemistry

He invented the concept of chemical potential, or “fuel” that makes chemical reactions work.


Question: when was stoichiometry first introduced?

History of chemistry

In 1876 he published his most famous contribution, “On the Equilibrium of Heterogeneous Substances”, a compilation of his work on thermodynamics and physical chemistry that put forward the concept of free energy to explain the basis of chemical equilibrium physics. [79]


Question: when was stoichiometry first introduced?

History of chemistry

The content of this essay was the beginning of Gibbs's theory regarding the phases of matter: he considered every state of matter a phase, and every substance was a component.


Question: when was stoichiometry first introduced?

History of chemistry

Gibbs took all the variables involved in a chemical reaction — temperature, pressure, energy, volume, and entropy — and put them into one simple equation known as the Gibbs phase rule.


Question: when was stoichiometry first introduced?

History of chemistry

The content of this paper is perhaps his most notable contribution, the introduction of the concept of free energy, now universally called Gibbs free energy in his honor.


Question: when was stoichiometry first introduced?

History of chemistry

Gibbs free energy relates the tendency of a physical or chemical system to simultaneously decrease its energy and increase its tacterness, or entropy, in spontaneous natural processes.


Question: when was stoichiometry first introduced?

History of chemistry

Gibbs's approach allowed the researchers to calculate the change in free energy in the process, such as in a chemical reaction, and how quickly it would occur.


Question: when was stoichiometry first introduced?

History of chemistry

Since almost all chemical processes and many physical processes involve such changes, his work has significantly influenced the theoretical and experiential aspects of this science.


Question: when was stoichiometry first introduced?

History of chemistry

In 1877, Ludwig Boltzmann established the statistical derivation of many important concepts of physics and chemistry, including entropy, and the velocity distribution of molecules in the gas phase. [80]


Question: when was stoichiometry first introduced?

History of chemistry

Together with Boltzmann and James Clerk Maxwell, Gibbs created a new branch of the theory of physics called statistical mechanics (a term he coined), which explained the laws of thermodynamics as a consequence of the statistical properties of large ensembles of particles.


Question: when was stoichiometry first introduced?

History of chemistry

Gibbs also researched the application of Maxwell's equations to physical optical problems.


Question: when was stoichiometry first introduced?

History of chemistry

Gibbs's derivation of the phenomenological laws of thermodynamics from the statistical properties of systems with many particles is presented in his highly influential major textbook Elementary Principles in Statistical Mechanics, published in 1902, a year before his death.


Question: when was stoichiometry first introduced?

History of chemistry

In that work, Gibbs revisited the relationship between the laws of thermodynamics and the statistical theory of molecular motion.


Question: when was stoichiometry first introduced?

History of chemistry

Going beyond the original function with a partial number of Fourier series at the point of discontinuity is known as the Gibbs phenomenon.


Question: when was stoichiometry first introduced?

History of chemistry

Late 19th century German engineer Carl von Linde's discovery of the continuous process of liquefaction of gas in large quantities formed the basis of modern refrigeration technology and provided the impetus and means to conduct scientific research at low temperatures and very high vacuum.


Question: when was stoichiometry first introduced?

History of chemistry

He developed a methyl ether refrigerator (1874) and an ammonia refrigerator (1876).


Question: when was stoichiometry first introduced?

History of chemistry

Although other refrigeration units had been developed earlier, Linde's works were the first to be designed with the aim of precise efficiency calculations.


Question: when was stoichiometry first introduced?

History of chemistry

In 1895 he established a large-scale factory for the production of liquid air.


Question: when was stoichiometry first introduced?

History of chemistry

Six years later he developed a method for separating pure liquid oxygen from liquid air resulting in extensive industrial conversion to processes utilizing oxygen (e.g., in steelmaking).


Question: when was stoichiometry first introduced?

History of chemistry

In 1883, Svante Arrhenius developed the theory of ions to explain conductivity in electrolytes. [81]


Question: when was stoichiometry first introduced?

History of chemistry

In 1884, Jacobus Henricus van't Hoff published Études de Dynamique chimique (Dynamic Chemistry Studies), an early study of chemical kinetics. [82]


Question: when was stoichiometry first introduced?

History of chemistry

In this work, van't Hoff entered the field of physical chemistry for the first time.


Question: when was stoichiometry first introduced?

History of chemistry

A particularly important point is its development on the general thermodynamic relationship between conversion heat and equilibrium displacement as a result of temperature variation.


Question: when was stoichiometry first introduced?

History of chemistry

At constant volume, the equilibrium in a system will tend to shift in the opposite direction from the temperature change imposed on the system.


Question: when was stoichiometry first introduced?

History of chemistry

Thus, a decrease in temperature causes heat to expand while increasing the temperature of heat absorption results.


Question: when was stoichiometry first introduced?

History of chemistry

This principle of moving equilibrium was later (1885) put into general form by Henry Louis Le Chatelier, who gave the principle to include compensation, with changes in volume, for changes in forced pressure.


Question: when was stoichiometry first introduced?

History of chemistry

The van't Hoff-Le Chatelier principle, or in short Le Chatelier's principle, explains the equilibrium response of dynamic chemistry to external pressure. [83]


Question: when was stoichiometry first introduced?

History of chemistry

In 1884, Hermann Emil Fischer proposed the structure of purines, a key structure in many biomolecules, which he later synthesized in 1898.


Question: when was stoichiometry first introduced?

History of chemistry

He also began researching the associated chemistry of glucose and sugar. [84]


Question: when was stoichiometry first introduced?

History of chemistry

In 1885, Eugene Goldstein named cathode rays, which were later found to be composed of electrons, and canal rays, later found to be positive hydrogen ions that had been stripped from their electrons in cathode ray tubes; these were later named protons. [85]


Question: when was stoichiometry first introduced?

History of chemistry

The year 1885 also underwent the publishing of J. H. van't Hoff's book L'Équilibre chimique dans les Systèmes gazeux ou dissous à I'État dilué (Chemical equilibrium in gas systems or highly dilute solutions), which discussed this theory of dilute solutions.


Question: when was stoichiometry first introduced?

History of chemistry

In his book, he showed that the “osmotic pressure” in a sufficiently dilute solution is proportional to the absolute concentration and temperature so that this pressure can be shown by a formula that simply deviates from the gas pressure formula by coefficient i.


Question: when was stoichiometry first introduced?

History of chemistry

He also determined the value of i by various methods, for example by means of vapor pressure and François-Marie Raoult's result on the freezing point drop.


Question: when was stoichiometry first introduced?

History of chemistry

Thus van't Hoff can prove that the laws of thermodynamics apply not only to gases, but also to dilute solutions.


Question: when was stoichiometry first introduced?

History of chemistry

His law of pressure, given general validity by the electrolytic dissociation theory of Arrhenius (1884-1887) - the first foreigner to come to work with him in Amsterdam (1888) - is considered the most comprehensive and important in the world of natural sciences.


Question: when was stoichiometry first introduced?

History of chemistry

In 1893, Alfred Werner discovered the octahedral structure of cobalt complexes, thus forming the field of science of coordination chemistry. [86]


Question: when was stoichiometry first introduced?

History of chemistry

Ramsay discovered noble gases The most famous discovery was made by Scottish chemist William Ramsay in inorganic chemistry.


Question: when was stoichiometry first introduced?

History of chemistry

Ramsay was inspired by the discovery of British physicist John Strutt, 3rd Baron Rayleigh in 1892 who stated that the atomic weight of nitrogen found in chemical compounds was lower than nitrogen found in the atmosphere.


Question: when was stoichiometry first introduced?

History of chemistry

He ascribed this difference to the lighter gases included in nitrogen chemical compounds, while Ramsay suspected the presence of hitherto undiscovered heavy gases in nitrogen in the atmosphere.


Question: when was stoichiometry first introduced?

History of chemistry

Using two different methods of removing all known gases from the air, Ramsay and Lord Rayleigh were able to announce in 1894 that they had discovered a monatomic gaseous element of an inert nature that makes up nearly 1 percent of the atmosphere; they named it argon.


Question: when was stoichiometry first introduced?

History of chemistry

The following year, Ramsay freed another inert gas from a mineral called kleveit; this proved to be helium, previously known only in the solar spectrum.


Question: when was stoichiometry first introduced?

History of chemistry

In his book The Gases of the Atmosphere (1896), Ramsay showed that the position of helium and argon in the periodic table of chemical elements suggests that there are at least three more noble gases that may exist.


Question: when was stoichiometry first introduced?

History of chemistry

In 1898 Ramsay and British chemist Morris W. Travers isolated these elements—called fluorescent, kripton, and xenon—from liquefied air at low temperatures and high pressures.


Question: when was stoichiometry first introduced?

History of chemistry

Sir William Ramsay worked with Frederick Soddy to demonstrate, in 1903, that alpha particles (helium nuclei) were continuously produced during the radioactive decay of radium samples.


Question: when was stoichiometry first introduced?

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Ramsay was awarded the Nobel Prize in Chemistry in 1904 in recognition of his “services in the discovery of inert gaseous elements in air, and the determination of their place in periodic systems.”


Question: when was stoichiometry first introduced?

History of chemistry

In 1897, J. J. Thomson discovered electrons using cathode ray tubes.


Question: when was stoichiometry first introduced?

History of chemistry

In 1898, Wilhelm Wien showed that a canal beam (positive ion flow) can be deflected by a magnetic field, and that the amount of deflection is proportional to the ratio of mass to charge.


Question: when was stoichiometry first introduced?

History of chemistry

This discovery would result in an analytical technique known as mass spectrometry in 1912. [87]


Question: when was stoichiometry first introduced?

History of chemistry

Marie and Pierre Curie Marie Skłodowska-Curie was a Polish-born French physicateur and chemist best known for her research on radioactivity.


Question: when was stoichiometry first introduced?

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She and her husband are thought to have laid the cornerstone of the nuclear age with their research on radioactivity.


Question: when was stoichiometry first introduced?

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Marie was fascinated with the work of Henri Becquerel, a French physicist who discovered in 1896 that uranium releases rays similar to X-rays discovered by Wilhelm Röntgen.


Question: when was stoichiometry first introduced?

History of chemistry

Marie Curie began studying uranium in late 1897 and theorized, according to a 1904 article she wrote for Century magazine, “that the emission of rays by uranium compounds is a property of the metal itself—that it is an atomic property of the element uranium regardless of its chemical or physical state .”


Question: when was stoichiometry first introduced?

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Curie took Becquerel's work several steps further, conducting his own experiments on uranium rays.


Question: when was stoichiometry first introduced?

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He found that his rays remained constant, no matter the condition or shape of the uranium.


Question: when was stoichiometry first introduced?

History of chemistry

The beam, he theorized, came from an elemental atomic structure.


Question: when was stoichiometry first introduced?

History of chemistry

This revolutionary idea created the field of atomic physics and Curie coined the word radioactivity to explain the phenomenon.


Question: when was stoichiometry first introduced?

History of chemistry

Pierre and Marie further explored radioactivity by working to separate substances in uranium ore and then using electrometers to take radiation measurements in order to 'track' unknown amounts of renic radioactive elements among the resulting fractions.


Question: when was stoichiometry first introduced?

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Working with the mineral pitchblende, the pair discovered a new radioactive element in 1898.


Question: when was stoichiometry first introduced?

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They named the element polonium, corresponding to Marie's home country, Poland.


Question: when was stoichiometry first introduced?

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On December 21, 1898, the Curie pair detected the presence of another radioactive material in pitchblende.


Question: when was stoichiometry first introduced?

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They presented these findings at the French Academy of Sciences on December 26, proposing that the new element be called radium.


Question: when was stoichiometry first introduced?

History of chemistry

The Curie pair then worked to isolate polonium and radium from natural compounds to prove that both were new elements.


Question: when was stoichiometry first introduced?

History of chemistry

In 1902, the Curie couple announced that they had produced one pure radium desigram, indicating its existence as a unique chemical element.


Question: when was stoichiometry first introduced?

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While it took three years for them to isolate radium, they were never able to isolate polonium.


Question: when was stoichiometry first introduced?

History of chemistry

Along with the discovery of two new elements and a discovery technique for isolating radioactive isotopes, Curie escorted the world's first study in the treatment of neoplasms, using radioactive isotopes.


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With Henri Becquerel and her husband, Pierre Curie, she was awarded the 1903 Nobel Prize in Physics.


Question: when was stoichiometry first introduced?

History of chemistry

He was the sole winner of the 1911 Nobel Prize in Chemistry.


Question: when was stoichiometry first introduced?

History of chemistry

She was the first woman to win the Nobel Prize, and she is the only woman to win the award in two different fields.


Question: when was stoichiometry first introduced?

History of chemistry

While working with Marie to extract pure substances from her grains, an endeavor that really required industrial resources but that they could achieve under relatively primitive conditions, Pierre himself concentrated on the study of the physics (including lumination and chemical effects) of new radiation.


Question: when was stoichiometry first introduced?

History of chemistry

Through the action of magnetic fields on the rays produced by radium, he proved the existence of positive, negative, and neutral electrical particles; this was what was later referred to by Ernest Rutherford as alpha, beta, and gamma rays.


Question: when was stoichiometry first introduced?

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Pierre later studied this radiation by calorimetry and also observed the physiological effects of radium, thus paving the way to radium therapy.


Question: when was stoichiometry first introduced?

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Among Pierre Curie's discoveries are ferromagnetic substances that exhibit critical temperature transitions, to which above those temperatures the substance loses its ferromagnetic behavior—this is known as the “Curie point”.


Question: when was stoichiometry first introduced?

History of chemistry

He was elected member of the Academy of Sciences (1905), having in 1903 together with Marie received the prestigious Davy Medal of the Royal Society and together with Marie and Becquerel got the Nobel Prize in Physics.


Question: when was stoichiometry first introduced?

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He was struck by a horse-drawn carriage on rue Dauphine, Paris in 1906 and died instantly.


Question: when was stoichiometry first introduced?

History of chemistry

His complete work was published in 1908.


Question: when was stoichiometry first introduced?

History of chemistry

Ernest Rutherford Chemistry and New Zealand-born physicist Ernest Rutherford are considered the “fathers of nuclear physics.”


Question: when was stoichiometry first introduced?

History of chemistry

Rutherford is best known for inventing the names alpha, beta, and gamma to classify various forms of radioactive “rays” that were poorly understood in his time (alpha and beta rays were beams of particles, whereas gamma rays were forms of high-energy electromagnetic radiation).


Question: when was stoichiometry first introduced?

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Rutherford deflected an alpha ray with an electric field and a magnetic field in 1903.


Question: when was stoichiometry first introduced?

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Working with Frederick Soddy, Rutherford explained that radioactivity was caused by transmutation of elements, now known to involve nuclear reactions.


Question: when was stoichiometry first introduced?

History of chemistry

He also observed that the radioactivity intensity of radioactive elements decreases over a unique and regular amount of time to the point of stability, and he named the time being half that by “half-life” (English: “half-life”).


Question: when was stoichiometry first introduced?

History of chemistry

In 1901 and 1902 he worked with Frederick Soddy to prove that atoms of one radioactive element would spontaneously transform into another atom, by ejecting pieces of atoms at high speeds.


Question: when was stoichiometry first introduced?

History of chemistry

In 1906 at the University of Manchester, Rutherford supervised an experiment conducted by his students Hans Geiger (known for his Geiger enumerators) and Ernest Marsden.


Question: when was stoichiometry first introduced?

History of chemistry

In the Geiger—Marsden experiments, a beam of alpha particles, generated through radioactive decay of radon, was directed normally onto a very thin sheet of gold foil in an evacuation vessel.


Question: when was stoichiometry first introduced?

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Under the prevailing model of plum pudding, the alpha particles must all pass through the foil and touch the detector screen, or at least have been deflected, by several degrees.


Question: when was stoichiometry first introduced?

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However, the reality took Rutherford by surprise.


Question: when was stoichiometry first introduced?

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Although many alpha particles made it through as expected, many others were deflected at small angles while others were reflected back to the alpha source.


Question: when was stoichiometry first introduced?

History of chemistry

They observed that the percentage of particles deflected with angles much greater than 90 degrees was minuscule.


Question: when was stoichiometry first introduced?

History of chemistry

The gold foil experiment showed large defections for a small fraction of the particles that were passed through.


Question: when was stoichiometry first introduced?

History of chemistry

Rutherford realized that, because some alpha particles are deflected or reflected, the atom has a concentrated positive charge center with a relatively large mass — Rutherford later referred to this positive center as the “atomic nucleus”.


Question: when was stoichiometry first introduced?

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The alpha particle has either mashed the positive center directly or passed through it with a distance close enough that it is affected by its positive charge.


Question: when was stoichiometry first introduced?

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Because many other particles pass through the gold foil, the positive center must be relatively small in size compared to the overall atomic size - meaning that those atoms are mostly open space.


Question: when was stoichiometry first introduced?

History of chemistry

From the results of his research, Rutherford developed an atomic model similar to the solar system, known as the Rutherford atomic model.


Question: when was stoichiometry first introduced?

History of chemistry

Like planets, electrons orbit the centers of atomic nuclei that are like the sun.


Question: when was stoichiometry first introduced?

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For his work in radiation and atomic nuclei, Rutherford received the 1908 Nobel Prize in Chemistry.


Question: when was stoichiometry first introduced?

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20th century In 1903, Mikhail Tsvet invented chromatography, an important analytical technique.


Question: when was stoichiometry first introduced?

History of chemistry

In 1904, Hantaro Nagaoka proposed an early model of atomic nuclear, in which electrons orbit a solid massive nucleus.


Question: when was stoichiometry first introduced?

History of chemistry

In 1905, Fritz Haber and Carl Bosch developed the Haber process for making ammonia, a milestone in industrial chemistry that had profound consequences in agriculture.


Question: when was stoichiometry first introduced?

History of chemistry

The Haber process, or Haber-Bosch process, combines nitrogen and hydrogen to form ammonia in an industrial quantity for fertilizer and ammunition production.


Question: when was stoichiometry first introduced?

History of chemistry

Food production for half the world's population today relies on this method to produce fertilizer.


Question: when was stoichiometry first introduced?

History of chemistry

Haber, together with Max Born, proposed the Born—Haber cycle as a method for evaluating the lattice energy of an ionic solid.


Question: when was stoichiometry first introduced?

History of chemistry

Haber has also been described as the “father of chemical warfare” for his work developing and spreading chlorine and other poisonous gases during World War I. In 1905, Albert Einstein explained Brown's motion in a way that definitively proved atomic theory.


Question: when was stoichiometry first introduced?

History of chemistry

Leo Baekeland invented bakelit, one of the first successful commercial plastics.


Question: when was stoichiometry first introduced?

History of chemistry

In 1909, American physicist Robert Andrews Millikan - who had studied in Europe under Walther Nernst and Max Planck - measured the charge of individual electrons with unprecedented accuracy through an oil droplet experiment, in which he measured the electric charge on small droplets of water (and then oil).


Question: when was stoichiometry first introduced?

History of chemistry

His study established that the electric charge of a given droplet is a multiple of its exact fundamental value — the charge of the electron — and thus is confirmation that all electrons have the same charge and mass.


Question: when was stoichiometry first introduced?

History of chemistry

Beginning in 1912, he spent several years researching and finally proving Albert Einstein's proposed linear relationship between energy and frequency, and provided the first direct photoelectric support for Planck's constant.


Question: when was stoichiometry first introduced?

History of chemistry

In 1923 Millikan was awarded the Nobel Prize in Physics.


Question: when was stoichiometry first introduced?

History of chemistry

In 1909, S. P. L. Sørensen discovered the concept of pH and developed a method for measuring acidity.


Question: when was stoichiometry first introduced?

History of chemistry

In 1911, Antonius van den Broek proposed the idea that elements on the periodic table are more precisely organized based on positive nuclear charge rather than atomic weight.


Question: when was stoichiometry first introduced?

History of chemistry

In 1911, the first Solvay Conference was held in Brussels, bringing together most of the most eminent scientists of the time.


Question: when was stoichiometry first introduced?

History of chemistry

In 1912, William Henry Bragg and William Lawrence Bragg proposed Bragg's law and established the field of X-ray crystallography, an important tool for elucidating the crystal structure of substances.


Question: when was stoichiometry first introduced?

History of chemistry

In 1912, Peter Debye developed the concept of molecular dipoles to explain asymmetric charge distributions in multiple molecules.


Question: when was stoichiometry first introduced?

History of chemistry

Niels Bohr In 1913, Niels Bohr, a Danish physicist, introduced the concept of quantum mechanics to the structure of atoms by proposing what is now known as the Bohr atomic model, in which strictly defined electrons exist only in circular orbits circling the atomic nuclei that similar to the risers on a ladder.


Question: when was stoichiometry first introduced?

History of chemistry

The Bohr model is a planetary model in which negatively charged electrons orbit a positively charged nucleus of small atoms similar to those of planets orbiting the Sun (except the orbits are not planar) - the gravitational force of the solar system is mathematically similar to the Coulomb (electric) force between nuclei that are positively charged and electrons are negatively charged.


Question: when was stoichiometry first introduced?

History of chemistry

In Bohr's model, electrons orbit nuclei in orbits that have a set size and energy — the energy level is said to be quantized, meaning that only orbits with certain radii are allowed; orbits located in between are completely absent.


Question: when was stoichiometry first introduced?

History of chemistry

The energy of the orbit is related to its size - that is, the lowest energy is present in the smallest


Question: when was stoichiometry first introduced?

History of chemistry

Bohr also postulated that electromagnetic radiation is absorbed or emitted as electrons move from one orbit to another.


Question: when was stoichiometry first introduced?

History of chemistry

Since only certain electron orbitals are permitted, the emission of light accompanying the leap of an electron from the excited energy state to the ground state results in an emission spectrum unique to each element.


Question: when was stoichiometry first introduced?

History of chemistry

Niels Bohr also researched the principle of complementarity, which states that an electron can be interpreted in two mutually exclusive and valid viewpoints.


Question: when was stoichiometry first introduced?

History of chemistry

Electrons can be interpreted as wave or particle models.


Question: when was stoichiometry first introduced?

History of chemistry

The hypothesis is that the incoming particles will invade the core and create the nucleus of the excited compound.


Question: when was stoichiometry first introduced?

History of chemistry

This formed the basis of his liquid drip model and later provided the basis of the theory for the explanation of nuclear fission.


Question: when was stoichiometry first introduced?

History of chemistry

In 1913, Henry Moseley, who worked according to Van den Broek's earlier ideas, introduced the concept of atomic number to correct the shortcomings of Mendeleev's periodic table, which was based on atomic weight.


Question: when was stoichiometry first introduced?

History of chemistry

The highlight of Frederick Soddy's career in radiochemistry was in 1913 with his formulation of the concept of isotopes, which held that certain elements are contained in two or more forms that have different atomic weights but are not chemically distinguishable.


Question: when was stoichiometry first introduced?

History of chemistry

He is remembered for proving the existence of isotopes of certain radioactive elements, and was also given recognition, along with others, for his discovery of the element protactinium in 1917.


Question: when was stoichiometry first introduced?

History of chemistry

In 1913, J. J. Thomson developed Wien's work by showing that charged subatomic particles could be separated based on the ratio of mass to charge, a technique known as mass spectrometry.


Question: when was stoichiometry first introduced?

History of chemistry

Gilbert N. Lewis The American physical chemist Gilbert N. Lewis laid the foundation of valence bond theory; he was instrumental in developing a bond theory based on the number of electrons in the outermost “valence” petal of an atom.


Question: when was stoichiometry first introduced?

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In 1902, when Lewis tried to explain valence to his students, he described atoms constructed from concentric sets of cubes with electrons at each angle.


Question: when was stoichiometry first introduced?

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This “cubic atom” describes the eight groups in the periodic table and represents his idea that chemical bonds are formed by electron transference to give each atom a complete set of eight outermost electrons (an “octet”).


Question: when was stoichiometry first introduced?

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Lewis's theory of chemical bonds continued to evolve and, in 1916, he published his seminal article “The Atom of the Molecule”, which suggested that a chemical bond was a pair of electrons shared by two atoms.


Question: when was stoichiometry first introduced?

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Lewis's model equates classical chemical bonding to sharing an electron pair between two atoms that bind.


Question: when was stoichiometry first introduced?

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Lewis introduced the “electron point diagram” in this paper to symbolize the electronic structure of atoms and molecules.


Question: when was stoichiometry first introduced?

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This structure is now known as the Lewis structure, and is discussed in almost every introductory book of chemistry.


Question: when was stoichiometry first introduced?

History of chemistry

Shortly after publishing his paper in 1916, Lewis became involved in military research.


Question: when was stoichiometry first introduced?

History of chemistry

He did not return to the subject of chemical bonding until 1923, when he willingly summarized his model in a short monograph entitled Valence and the Structure of Atoms and Molecules.


Question: when was stoichiometry first introduced?

History of chemistry

His attention back on the issue was largely inspired by the activities of American chemist and General Electric researcher Irving Langmuir, who between 1919 and 1921 popularized and explained Lewis's model.


Question: when was stoichiometry first introduced?

History of chemistry

Langmuir later introduced the term covalent bond.


Question: when was stoichiometry first introduced?

History of chemistry

In 1921, Otto Stern and Walther Gerlach established the concept of quantum mechanical spin in subatomic particles.


Question: when was stoichiometry first introduced?

History of chemistry

For cases not involving co-ownership, Lewis in 1923 developed a theory of acid and base electron pairs: Lewis redefined an acid as any atom or molecule with an incomplete octet so capable of receiving electrons from another atom; bases were, of course, donors electrons.


Question: when was stoichiometry first introduced?

History of chemistry

His theory is known as Lewis's concept of acids and bases.


Question: when was stoichiometry first introduced?

History of chemistry

In 1923, G. N. Lewis and Merle Randall published Thermodynamics and the Free Energy of Chemical Substances, the first modern treatise on chemical thermodynamics.


Question: when was stoichiometry first introduced?

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The 1920s were witnesses to the rapid adoption and application of electron pair bonds of the Lewis model in the fields of organic chemistry and coordination chemistry.


Question: when was stoichiometry first introduced?

History of chemistry

In organic chemistry, this was primarily due to the efforts of British chemists Arthur Lapworth, Robert Robinson, Thomas Lowry, and Christopher Ingold; while in coordination chemistry, the Lewis bonding model was promoted through the efforts of American chemist Maurice Huggins and British chemist Nevil Sidgwick.


Question: when was stoichiometry first introduced?

History of chemistry

Quantum mechanics In 1924, French quantum physicist Louis de Broglie published his thesis, in which he introduced a revolutionary theory of electron waves based on wave—particle duality in his thesis.


Question: when was stoichiometry first introduced?

History of chemistry

In his time, wave and particle interpretations of light and matter were seen as conflicting with each other, but de Broglie suggested that these seemingly different characteristics were precisely the same behavior if observed from different perspectives — that particles could behaves like waves, and waves (radiation) can behave like particles.


Question: when was stoichiometry first introduced?

History of chemistry

Broglie's proposal offers an explanation of the finite motion of electrons inside an atom.


Question: when was stoichiometry first introduced?

History of chemistry

The first publication of Broglie's ideas about “waves of matter” did little to interest other physicists, but copies of his doctoral thesis fell into the hands of Einstein, who responded to it with great enthusiasm.


Question: when was stoichiometry first introduced?

History of chemistry

Einstein emphasized the importance of Broglie's work explicitly and by further developing regarding it.


Question: when was stoichiometry first introduced?

History of chemistry

In 1925, Austrian-born physicist Wolfgang Pauli developed the Pauli exclusion principle, which states that no two electrons surrounding one atomic nucleus can occupy the same quantum state simultaneously, as described by four quantum numbers.


Question: when was stoichiometry first introduced?

History of chemistry

Pauli made major contributions to quantum mechanics and quantum field theory - he was awarded the 1945 Nobel Prize in Physics for his discovery of Pauli's exclusion principle - as well as to the physics of solids (English: solid-state physics), and he successfully made a hypothesis about the existence of neutrinos.


Question: when was stoichiometry first introduced?

History of chemistry

In addition to his original work, he wrote advanced syntheses of several areas of physics theory considered classics according to the scientific literature.


Question: when was stoichiometry first introduced?

History of chemistry

In 1926 at the age of the 39th, Austrian theoretical physicist Erwin Schrödinger produced a paper that gave the basis of quantum wave mechanics.


Question: when was stoichiometry first introduced?

History of chemistry

In the paper, he described his partial differential equations which are basic equations of quantum mechanics that have connections to atomic mechanics such as the relationship between Newton's equations of motion and planetary astronomy.


Question: when was stoichiometry first introduced?

History of chemistry

Adopting a proposal made by Louis de Broglie in 1924 stating that particles of matter have the property of dualism and in some situations act like waves, Schrödinger introduced a theory describing the behavior of such systems through the wave equation which is now known as the Schrödinger equation.


Question: when was stoichiometry first introduced?

History of chemistry

Schrödinger equation solving, unlike Newton's equation solving, is a wave function that can only be related to possible events of physics.


Question: when was stoichiometry first introduced?

History of chemistry

An easily visualized sequence of planetary orbit events, in quantum mechanics, is replaced by a more abstract notion of probability.


Question: when was stoichiometry first introduced?

History of chemistry

(This aspect of quantum theory made Schrödinger and several other physicists very unhappy, and he devoted much of the rest of his life to formulating philosophical objections to interpretations of his theories that had been generally accepted, and that he had done much for created the theory.)


Question: when was stoichiometry first introduced?

History of chemistry

German theoretical physicist Werner Heisenberg is one of the key creators of quantum mechanics.


Question: when was stoichiometry first introduced?

History of chemistry

In 1925, Heisenberg found a way to formulate quantum mechanics in matrix terms.


Question: when was stoichiometry first introduced?

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For that discovery, he was awarded the Nobel Prize in Physics in 1932.


Question: when was stoichiometry first introduced?

History of chemistry

In 1927 he published his principle of uncertainty, on which he built the philosophy that popularized his name.


Question: when was stoichiometry first introduced?

History of chemistry

Heisenberg was able to show that if you studied an electron in an atom you could indicate its location (location of an electron) or its direction of passage (electron velocity), but it was impossible to reveal both at the same time.


Question: when was stoichiometry first introduced?

History of chemistry

He also made important contributions to the hydrodynamics theory of turbulent flows, atomic nuclei, ferromagnetic, cosmic rays, and subatomic particles, and he was instrumental in planning the first West German nuclear reactor at Karlsruhe, together with a research reactor in Munich, in 1957.


Question: when was stoichiometry first introduced?

History of chemistry

There was considerable controversy surrounding his work on atomic research during World War II.


Question: when was stoichiometry first introduced?

History of chemistry

Quantum chemistry Some saw the birth of quantum chemistry along with the discovery of the Schrödinger equation and its application to hydrogen atoms in 1926.


Question: when was stoichiometry first introduced?

History of chemistry

However, a 1927 article from Walter Heitler and Fritz Londonref>W.


Question: when was stoichiometry first introduced?

History of chemistry

Heitler and F. London, Wechselwirkung neutraler Atome und Homöopolare Bindung nach der Quantenmechanik, Z. Physik, 44, 455 (1927). </ref> isoften known as the first milestone in the history of quantum chemistry.


Question: when was stoichiometry first introduced?

History of chemistry

This was the first application of quantum mechanics on diatomic hydrogen molecules, and with also on chemical bonding phenomena.


Question: when was stoichiometry first introduced?

History of chemistry

In the following years much progress was achieved by, among them Edward Teller, Robert S. Mulliken, Max Born, J. Robert Oppenheimer, Linus Pauling, Erich Hückel, Douglas Hartree, Vladimir Aleksandrovich Fock.


Question: when was stoichiometry first introduced?

History of chemistry

However, skepticism persists towards the general forces of quantum mechanics applied to complex chemical systems.


Question: when was stoichiometry first introduced?

History of chemistry

The situation around 1930 was described by Paul Dirac: [88] The fundamental laws of physics necessary for the mathematical theory of most physics and the whole of chemistry have been fully known, and the difficulty is that the actual application of these laws causes the equations to become too tricky to be solvable.


Question: when was stoichiometry first introduced?

History of chemistry

Therefore, it became desirable that an approximation of practical methods for applying quantum mechanics should be developed, which could lead to an explanation of the main features of complex atomic systems without too much computing.


Question: when was stoichiometry first introduced?

History of chemistry

Therefore, the methods of quantum mechanics developed in the 1930s and 1940s are often referred to as molecular physics or theoretical atomic physics to underscore the fact that the theory is more an application of quantum mechanics to chemistry and spectroscopy than an answer to chemically relevant question.


Question: when was stoichiometry first introduced?

History of chemistry

In 1951, the article that was a milestone in quantum chemistry was Clemens C. J. Roothaan's seminal paper on Roothaan's equations. [89]


Question: when was stoichiometry first introduced?

History of chemistry

This opens the way to solving the swakonsistent field equation for small molecules such as hydrogen or nitrogen.


Question: when was stoichiometry first introduced?

History of chemistry

Such computing was carried out with the help of integral tables calculated using the most advanced computers of its time.


Question: when was stoichiometry first introduced?

History of chemistry

In the 1940s many physicists switched from molecular physics or atomic physics to nuclear physics (such as J. Robert Oppenheimer or Edward Teller).


Question: when was stoichiometry first introduced?

History of chemistry

Glenn T. Seaborg is an American nuclear chemist best known for his work on the isolation and identification of transuranium elements (which are heavier than uranium).


Question: when was stoichiometry first introduced?

History of chemistry

He shared the 1951 Nobel Prize in Chemistry with Edwin Mattison McMillan for their discovery of the element transuranium which they made separately.


Question: when was stoichiometry first introduced?

History of chemistry

Seaborgium was named in his honor, making him the only figure, alongside Albert Einstein, whose name was enshrined as an elemental name when the one concerned was alive.


Question: when was stoichiometry first introduced?

History of chemistry

Molecular biology and biochemistry In the mid-20th century, in principle, the integration of physics and chemistry was extensive, with chemical properties explained as a result of the electronic structure of atoms; Linus Pauling's book entitled The Nature of the Chemical Bond uses the principles of quantum mechanics to infer bond angles in increasingly complicated molecules.


Question: when was stoichiometry first introduced?

History of chemistry

Although some principles deduced from quantum mechanics can qualitatively predict some chemical features for biologically relevant molecules, but the conclusions are still more inclined to a collection of rules, observations, and prescriptions than to ab initio quantitative methods that strictly, at least until the end of the 20th century.


Question: when was stoichiometry first introduced?

History of chemistry

This heuristic approach succeeded through its difficult period when in 1953 James Watson and Francis Crick deduced the double helical structure of DNA by making a model constrained by and informed by the chemical knowledge of its constituent parts as well as the X-ray diffraction patterns obtained by Rosalind Franklin. [90]


Question: when was stoichiometry first introduced?

History of chemistry

The discovery sparked an explosion of research into the biochemistry of life.


Question: when was stoichiometry first introduced?

History of chemistry

In the same year, the Miller-Urey experiment showed that the basic elements of proteins, simple amino acids, could be self-constructed from simpler molecules in simulations of primordial processes on Earth.


Question: when was stoichiometry first introduced?

History of chemistry

While there are still many questions about the true nature of the origin of life, this is the first attempt by chemists to study hypothetical processes in the laboratory under controlled conditions.


Question: when was stoichiometry first introduced?

History of chemistry

In 1983 Kary Mullis devised a method for in-vitro amplification of DNA, known as polymerase chain reaction (English: polymerase chain reaction, PCR), which revolutionized the chemical processes used in laboratories to manipulate it.


Question: when was stoichiometry first introduced?

History of chemistry

PCR can be used to synthesize specific pieces of DNA and enable DNA sequencing of organisms, culminating in a major project of the human genome.


Question: when was stoichiometry first introduced?

History of chemistry

An important piece in the double helix puzzle was solved by one of Pauling's pupils Matthew Meselson and Frank Stahl, the result of their collaboration (the Meselson—Stahl experiment) has been referred to as “the most beautiful experiment in biology”.


Question: when was stoichiometry first introduced?

History of chemistry

They use centrifugation techniques that sort molecules according to differences in weight.


Question: when was stoichiometry first introduced?

History of chemistry

Since nitrogen atoms are components of DNA, they are labeled so that they are traced in bacterial replication.


Question: when was stoichiometry first introduced?

History of chemistry

Late 20th century In 1970, John Pople developed a Gaussian program that greatly facilitated the calculation of computational chemistry. [91]


Question: when was stoichiometry first introduced?

History of chemistry

In 1971, Yves Chauvin offered an explanation of the mechanism of olefin metathesis reaction [92].


Question: when was stoichiometry first introduced?

History of chemistry

In 1975, Karl Barry Sharpless and his group discovered stereoselective oxidation reactions including Sharpless epoxidation, [93] [94] Sharpless asymmetric dihydroxylation, [95] [96] [97] and Sharpless oxyamination. [98] [99] [100] In 1985, Harold Kroto, Robert Curl and Richard Smalley discovered fulerenas, a class of large carbon molecules resembling geodesic domes designed by architect R. Buckminster Fuller. [101]


Question: when was stoichiometry first introduced?

History of chemistry

In 1991, Sumio Iijima used electron microscopy to discover a type of cylindrical fulerene known as carbon nanotube, although he had done so earlier in 1951.


Question: when was stoichiometry first introduced?

History of chemistry

This material is an important component in the field of nanotechnology. [102]


Question: when was stoichiometry first introduced?

History of chemistry

In 1994, Robert A. Holton and his group achieved a total synthesis of Taxol for the first time. [103] [104] [105] In 1995, Eric Cornell and Carl Wieman made the first Bose-Einstein condensate, a substance that displays the properties of quantum mechanics on a macroscopic scale. [106]


Question: when was stoichiometry first introduced?

History of chemistry

Mathematics and chemistry Classically, before the 20th century, chemistry was defined as the science of the nature of matter along with its transformation.