The dependence of the rate of a chemical reaction on temperature is determined by the Van't Hoff rule.

Dutch chemist Van't Hoff Jacob Hendrick, the founder of stereochemistry, became the first Nobel Prize winner in chemistry in 1901. It was awarded to him for his discovery of the laws of chemical dynamics and osmotic pressure. Van't Hoff introduced ideas about the spatial structure of chemical substances. He was confident that progress in fundamental and applied research in chemistry could be achieved using physical and mathematical methods. Having developed the theory of reaction rates, he created chemical kinetics.

Chemical reaction rate

So, the kinetics of chemical reactions is the study of the rate of occurrence, what chemical interaction occurs during the reaction process, and the dependence of reactions on various factors. Different reactions have different rates of occurrence.

Chemical reaction rate directly depends on the nature of the chemicals entering the reaction. Some substances, such as NaOH and HCl, can react in a fraction of a second. And some chemical reactions last for years. An example of such a reaction is the rusting of iron.

The rate of the reaction also depends on the concentration of the reactants. The higher the concentration of reagents, the higher the reaction rate. During the reaction, the concentration of reagents decreases, therefore, the reaction rate slows down. That is, at the initial moment the speed is always higher than at any subsequent moment.

V = (C end – From start)/(t end – t start)

Reagent concentrations are determined at certain time intervals.

Van't Hoff's rule

An important factor on which the rate of reactions depends is temperature.

All molecules collide with others. The number of impacts per second is very high. But, nevertheless, chemical reactions do not occur at great speed. This happens because during the reaction the molecules must assemble into an activated complex. And only active molecules whose kinetic energy is sufficient for this can form it. With a small number of active molecules, the reaction proceeds slowly. As the temperature increases, the number of active molecules increases. Consequently, the reaction rate will be higher.

Van't Hoff believed that the rate of a chemical reaction is a natural change in the concentration of reacting substances per unit time. But it is not always uniform.

Van't Hoff's rule states that with every 10° increase in temperature, the rate of a chemical reaction increases by 2-4 times .

Mathematically, van't Hoff's rule looks like this:

Where V 2 t 2, A V 1 – reaction rate at temperature t 1 ;

ɣ - temperature coefficient of reaction rate. This coefficient is the ratio of rate constants at temperature t+10 And t.

So, if ɣ = 3, and at 0 o C the reaction lasts 10 minutes, then at 100 o C it will last only 0.01 seconds. A sharp increase in the rate of a chemical reaction is explained by an increase in the number of active molecules with increasing temperature.

Van't Hoff's rule is applicable only in the temperature range of 10-400 o C. Reactions in which large molecules participate do not obey Van't Hoff's rule.

After working for a short time at a sugar factory, V.-G. in 1871 he became a student at the Faculty of Science and Mathematics at Leiden University. However, the very next year he moved to the University of Bonn to study chemistry under the guidance of Friedrich August Kekule. Two years later, the future scientist continued his studies at the University of Paris, where he completed his dissertation. Returning to the Netherlands, he presented her for defense at the University of Utrecht.

At the very beginning of the 19th century. French physicist Jean Baptiste Biot noticed that the crystalline forms of some chemicals can change the direction of rays of polarized light passing through them. Scientific observations have also shown that some molecules (called optical isomers) rotate the plane of light in the opposite direction to that in which other molecules rotate it, although both are the same type of molecules and consist of the same number of atoms. Observing this phenomenon in 1848, Louis Pasteur hypothesized that such molecules were mirror images of each other and that the atoms of such compounds were arranged in three dimensions.

In 1874, a few months before defending his dissertation, V.-G. published an 11-page paper entitled "An Attempt to Extend to Space the Present Structural Chemical Formulae. With an Observation on the Relation Between Optical Activity and the Chemical Constituents of Organic Compounds").

In this paper, he proposed an alternative to the two-dimensional models that were then used to depict the structures of chemical compounds. V.-G. suggested that the optical activity of organic compounds is associated with an asymmetric molecular structure, with the carbon atom located in the center of the tetrahedron, and in its four corners there are atoms or groups of atoms that differ from each other. Thus, the interchange of atoms or groups of atoms located in the corners of the tetrahedron can lead to the appearance of molecules that are identical in chemical composition, but are mirror images of each other in structure. This explains the differences in optical properties.

Two months later in France, a person who worked on this problem independently of V.-G. came to similar conclusions. his friend at the University of Paris, Joseph Achille Le Bel. Having extended the concept of a tetrahedral asymmetric carbon atom to compounds containing carbon-carbon double bonds (shared edges) and triple bonds (shared edges), V.-G. argued that these geometric isomers socialize the edges and faces of the tetrahedron. Since the Van't Hoff–Le Bel theory was extremely controversial, W.-G. did not dare to submit it as a doctoral dissertation. Instead, he wrote a dissertation on cyanoacetic and malonic acids and received a doctorate in chemistry in 1874.

Considerations V.-G. on asymmetric carbon atoms were published in a Dutch journal and made little impact until his paper was translated into French and German two years later. At first, the van't Hoff–Le Bel theory was ridiculed by famous chemists such as A.V. Hermann Kolbe, who called it “fantastic nonsense, completely devoid of any factual basis and completely incomprehensible to a serious researcher.” However, over time, it formed the basis of modern stereochemistry - a field of chemistry that studies the spatial structure of molecules.

The formation of a scientific career by V.-G. it was going slowly. At first he had to give private lessons in chemistry and physics by advertisement, and only in 1976 he received a position as lecturer in physics at the Royal Veterinary School in Utrecht. The following year he becomes lecturer (and later professor) of theoretical and physical chemistry at the University of Amsterdam. Here, over the next 18 years, he gave five lectures every week on organic chemistry and one lecture on mineralogy, crystallography, geology and paleontology, and also directed a chemical laboratory.

Unlike most chemists of his time, V.-G. had a thorough mathematical background. It was useful to the scientist when he took on the difficult task of studying the rates of reactions and the conditions affecting chemical equilibrium. As a result of the work done, V.-G. Depending on the number of molecules involved in the reaction, he classified chemical reactions as monomolecular, bimolecular and multimolecular, and also determined the order of chemical reactions for many compounds.

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After the onset of chemical equilibrium in the system, both forward and reverse reactions proceed at the same rate without any final transformations. If the pressure in such a system increases (conditions or the concentration of its components change), the equilibrium point shifts so that the pressure decreases. This principle was formulated in 1884 by the French chemist Henri Louis Le Chatelier. In the same year V.-G. applied the principles of thermodynamics in formulating the principle of mobile equilibrium resulting from changes in temperature. At the same time, he introduced the now generally accepted designation for the reversibility of a reaction with two arrows pointing in opposite directions. The results of his research V.-G. outlined in “Essays on Chemical Dynamics” (“Etudes de dynamique chimique”), published in 1884.

In 1811, the Italian physicist Amedeo Avogadro found that equal volumes of any gases at the same temperature and pressure contain the same number of molecules. V.-G. came to the conclusion that this law is also valid for dilute solutions. The discovery he made was very important, since all chemical and metabolic reactions within living beings occur in solutions. The scientist also experimentally established that osmotic pressure, which is a measure of the tendency of two different solutions on both sides of the membrane to equalize their concentration, in weak solutions depends on concentration and temperature and, therefore, obeys the gas laws of thermodynamics. Conducted by V.-G. studies of dilute solutions were the basis for the theory of electrolytic dissociation by Svante Arrhenius. Subsequently, Arrhenius moved to Amsterdam and worked together with W.-G.

In 1887 V.-G. and Wilhelm Ostwald took an active part in the creation of the “Journal of Physical Chemistry” (“Zeitschrift fur Physikalische Chemie”). Ostwald had recently taken up the vacant position as professor of chemistry at the University of Leipzig. V.-G. was also offered this position, but he rejected the offer, since the University of Amsterdam announced its readiness to build a new chemical laboratory for the scientist. However, when V.-G. It became obvious that the pedagogical work he carried out in Amsterdam, as well as the performance of administrative duties, interfered with his research activities, he accepted the offer of the University of Berlin to take the place of professor of experimental physics. It was agreed that here he would lecture only once a week and that a fully equipped laboratory would be placed at his disposal. This happened in 1896.

Working in Berlin, W.-G. became involved in the application of physical chemistry to solve geological problems, in particular in the analysis of oceanic salt deposits in Stasfurt. Before the First World War, these deposits almost entirely provided potassium carbonate for the production of ceramics, detergents, glass, soap, and especially fertilizers. V.-G. He also began to study problems of biochemistry, in particular the study of enzymes that serve as catalysts for chemical changes necessary for living organisms.

In 1901 V.-G. became the first winner of the Nobel Prize in Chemistry, which was awarded to him “in recognition of the enormous importance of his discovery of the laws of chemical dynamics and osmotic pressure in solutions.” Introducing V.-G. on behalf of the Royal Swedish Academy of Sciences, S.T. Odner called the scientist the founder of stereochemistry and one of the creators of the doctrine of chemical dynamics, and also emphasized that the research of V.-G. "contributed significantly to the remarkable achievements of physical chemistry."

In 1878 V.-G. married the daughter of a Rotterdam merchant, Johanna Francine Mees. They had two daughters and two sons.

Throughout his life, V.-G. carried a keen interest in philosophy, nature, poetry. He died of pulmonary tuberculosis on March 1, 1911 in Steglitz, Germany (now part of Berlin).

In addition to the Nobel Prize, W.-G. was awarded the Davy Medal of the Royal Society of London (1893) and the Helmholtz Medal of the Prussian Academy of Sciences (1911). He was a member of the Royal Netherlands and Prussian Academies of Sciences, the British and American Chemical Societies, the American National Academy of Sciences and the French Academy of Sciences. V.-G. He was awarded honorary degrees from the University of Chicago, Harvard and Yale.

JACOB V'ANT HOFF

Van't Hoff received the first Nobel Prize in chemistry for his discovery of the laws of chemical dynamics and osmotic pressure. This high award marked the importance of the young field of science - physical chemistry.

A scientist who enjoyed universal respect, a member of fifty-two scientific societies and academies, and an honorary doctor of many higher educational institutions, Van't Hoff left behind a number of fundamental theories that are of enduring importance for chemistry today. The scientist’s ideas, ideas and views played a big role in developing the foundations of modern mineralogy, as well as for the development of biology. Van't Hoff entered the history of science as one of the founders of stereochemistry, the doctrine of chemical equilibrium and chemical kinetics, the osmotic theory of solutions and chemical geology.

Jacob Henrik Van't Hoff was born on August 30, 1852 in Holland, in Rotterdam, into the family of a doctor. Members of this family were repeatedly elected burgomasters and held other elected positions in city government.

Already in elementary school, teachers noticed the boy’s love for music and poetry. Later he showed remarkable abilities in the exact natural sciences. After finishing school in 1869, Jacob entered the Polytechnic in Delft. And here he was significantly superior to his fellow students in terms of knowledge, and therefore in 1871 he was admitted to Leiden University without an entrance exam. Later at this university Van't Hoff passed the candidate's exam.

But he didn’t like it in Leiden, and he went to Bonn to visit the famous chemist Kekula. After the discovery of propionic acid by young scientists, Kekule recommended that his student go to Paris to see Professor Wurtz, a specialist in organic synthesis.

In Paris, Jacob became close to the French chemist-technologist Joseph Achille Le Bel. Both followed with interest Pasteur's research in the field of optical isomerism.

In December 1874 Van't Hoff defended his doctorate at the University of Utrecht and in 1876 began teaching at the local veterinary school. In the autumn of 1874 he published in Utrecht a small work with a long title: “A proposal for the spatial application of modern structural chemical formulas, together with notes on the relation between the optical rotational power and the chemical constitution of organic compounds.”

Van't Hoff introduced principles into science that made it possible to consider the structure of chemical compounds from a new perspective. The idea that in a methane molecule four hydrogen atoms are evenly distributed in space and therefore we can talk about the tetrahedral shape of the molecule brings us back to Kekule’s views. In the model proposed by Van't Hoff, the four valences of a carbon atom are directed towards the vertices of the tetrahedron, in the center of which this atom is located. Using such a model, Van't Hoff suggested that due to the connection of atoms or atomic groups with carbon, the tetrahedron can be asymmetrical, and expressed the idea of ​​an asymmetric carbon atom. He wrote: “In the case when the four affinities of the carbon atom are saturated with four different monovalent groups, it is possible to obtain two and only two different tetrahedra, which are mirror images of each other and cannot be mentally combined in any way, that is, we are dealing with two structural formulas in space."

Van't Hoff's new article “Chemistry in Space” (1875), where he expressed all these considerations, served as the beginning of a new stage in the development of organic chemistry. Soon he received a letter from Professor Wislicenus, one of the most famous specialists in this field: “I would like to receive consent to have your article translated into German by my assistant Dr. Hermann. Your theoretical development brought me great joy. I see in it not only an extremely ingenious attempt to explain hitherto incomprehensible facts, but I also believe that in our science... it will acquire epoch-making significance.”

The translation of the article was published in 1876. By this time, van't Hoff had received a position as assistant physicist at the Veterinary Institute in Utrecht.

A major role in popularizing Van't Hoff's new views involuntarily went to Professor G. Kolbe from Leipzig. In a sharp form, he expressed his comments regarding the article of the Dutch scientist: “Some doctor J.G. Van't Hoff, of the Veterinary Institute in Utrecht, apparently has no taste for precise chemical research. It is much more convenient for him to mount Pegasus (probably borrowed from the Veterinary Institute) and proclaim in his Chemistry in Space that, as it seemed to him during his bold flight to chemical Parnassus, atoms are located in interplanetary space. Naturally, everyone who read this sharp rebuke was interested in Van't Hoff's theory. Thus began its rapid spread in the scientific world. Now Van't Hoff could repeat the words of his idol Byron: “One morning I woke up as a celebrity.” A few days after the publication of the article, Kolbe van't Hoff was offered a teaching position at the University of Amsterdam, and in 1878 he became a professor of chemistry.

From 1877 to 1896 Van't Hoff was professor of chemistry, mineralogy and geology at the recently founded University of Amsterdam. His wife Jenny van't Hoff-Mees was always by his side. She managed not only to take care of the house and children, but also managed to create a real creative atmosphere for her husband.

Van't Hoff's interests in the search for the most general laws reappeared in his great work “Views on Organic Chemistry.” But soon the scientist moved on to studying chemical dynamics. He outlined his views on this issue in the book “Essays on Chemical Dynamics” (1884).

Van't Hoff developed the theory of reaction rates and thereby created the foundations of chemical kinetics. He defined the reaction rate as a natural, but not always uniform, change in the concentration of reacting substances per unit time. He managed to formulate this pattern in a general mathematical form. The establishment of the dependence of the reaction rate on the number of interacting molecules, as well as Van't Hoff's closely related new ideas about the nature of chemical equilibrium, significantly contributed to the significant progress of theoretical chemistry.

At the same time, it was found that chemical equilibrium, considered by Van't Hoff as the result of two oppositely directed reactions occurring at the same speed (reversible process), depends on temperature. Van't Hoff associated ideas about chemical equilibrium with the two principles of thermodynamics already known at that time. The most important result of this work was Van't Hoff's derivation of a mathematical formula that reflected the relationship between temperature and heat of reaction with the equilibrium constant. This pattern is now known as the Van't Hoff reaction isochore equation.

Another major contribution of van't Hoff to theoretical chemistry during his Amsterdam period was the discovery of the analogy between osmotic and gas pressure. Based on the empirical laws formulated by Raoult about increasing the boiling point and decreasing the freezing point of solutions, Van't Hoff developed the osmotic theory of solutions in 1885.

K. Manolov tells in his book how the scientist came to this discovery: “Why not imagine the system in an osmometer “water - semi-permeable partition - solution” in the form of a cylinder with a piston? The solution is at the bottom of the cylinder, the piston is a partition, and above it is water. This is the basic method of thermodynamics. The principles of gas thermodynamics also apply to the properties of dilute solutions.”

Van't Hoff drew a cylinder with a piston, in the space under the piston he wrote “Solution”, and above the piston he wrote “Water”. Arrows directed from the solution to the water showed that there was pressure in the solution, which tended to lift the piston up.

“First you need to calculate what work is required for the piston to move upward under the influence of osmotic pressure, but you can do the opposite - find out what work is required to return the piston down, overcoming the osmotic pressure.”

Van't Hoff carried out mathematical calculations, filling out the sheet with formulas, and here it is, the final result!

“Incredible! The dependence is exactly the same as for gases! The expression is absolutely identical to the Clapeyron-Clausius equation!” Van't Hoff took the sheet and repeated all the calculations. “Same result! The laws of osmotic pressure are identical to the gas laws. If the constant has the same value, then we can treat the molecules of the dilute substance as gas molecules, imagining that the solvent has been removed from the container. The constant can be calculated from Pfeffer’s data.” He picked up the notebook again, and the pen quickly slid across the paper. For sugar solutions, the constant had the same value as the gas constant. The analogy was complete."

Van't Hoff established that dissolved molecules produce an osmotic pressure equal to the pressure that the same molecules would exert if they, in a gaseous state, occupied a volume equal to the volume of the solution. This fundamental discovery showed the unity of the laws of physics and chemistry (although the causes of osmotic pressure were not revealed).

Van't Hoff also had a great influence on the further development of the theory of dissociation, having studied in his work “Chemical equilibrium in systems of gases and dilute solutions” (1886).

In March 1896, Van't Hoff left Amsterdam, moving to Berlin at the invitation of the Prussian Academy of Sciences. In accordance with the proposal of Max Planck and Emil Fischer, a special research laboratory was created for Van't Hoff at the Academy of Sciences, and the scientist himself was immediately elected as a full member and honorary professor at the University of Berlin.

In Germany, he carried out extensive experimental and theoretical work, which helped to establish the conditions for the formation of deposits of potassium salts and create a rational technology for their processing.

The scientist was in America when he learned that he had received the first Nobel Prize in chemistry “in recognition of the enormous importance of his discovery of the laws of chemical dynamics and osmotic pressure in solutions.” On December 10, 1901, outstanding scientists of the world gathered in Stockholm. The ceremony in the festively lit hall of the Swedish Academy of Sciences was truly unforgettable.

In the evening, at the banquet, Van't Hoff had the opportunity to express his heartfelt gratitude for the great honor bestowed upon him, to the Committee for the Nobel Prize in Chemistry and personally to its chairman, Professor P. Kleve.

Representing the scientist on behalf of the Royal Swedish Academy of Sciences, S.T. Odner called the scientist the founder of stereochemistry and one of the creators of the doctrine of chemical dynamics, and also emphasized that van’t Hoff’s research “made a significant contribution to the remarkable achievements of physical chemistry.”

In the following days, according to the requirements of the Nobel Committee, the recipients were required to make presentations on the scientific achievements for which they were awarded the prize. Van't Hoff spoke about the theory of solutions in his lecture.

The scientist continued to work, but a long-standing serious illness prevented Van't Hoff from further studying the synthetic action of enzymes in a living plant organism.

(1852-1911) Dutch chemist and physicist

The development of chemistry is unimaginable without the discoveries of Jacob Hendrik Van't Hoff, who created an entire system of sciences - stereochemistry, chemical kinetics, physical chemistry. He was one of the first to understand that it was the unification of two fundamental sciences - physics and chemistry - that makes it possible to take a fresh look at the simplest phenomena and objects.

Jacob Hendrik van't Hoff was born in Rotterdam, the son of a successful doctor, who was also a famous Shakespeare expert in Holland. Jacob was the third of seven children born into the family. Initially, he showed an aptitude for mathematics and only changed this attachment at the city high school. Jacob became friends with the chemistry teacher and became a regular in the small school laboratory. And in the last grade, he already worked in a home laboratory, which he himself equipped in the barn.

While finishing school, Jacob dreamed of a career as a chemist. However, his parents, considering research work unpromising, persuaded their son to begin studying engineering at the Polytechnic School in Delft. In just two years, Van't Hoff completed a three-year training program and topped the final exam. There he became interested in philosophy, mathematics and poetry (especially the works of George Byron).

After working for a short time at a sugar factory, the young man realized that he had to continue his education. He went to Leiden and in 1871 became a student in the Faculty of Science and Mathematics at Leiden University. However, the very next year he moved to the University of Bonn to study chemistry under the guidance of Friedrich August Kekule. Two years later, the future scientist continued his studies at the University of Paris with L. Wurtz, where he completed his dissertation. Returning to the Netherlands, he presented her for defense at the University of Utrecht.

Jacob van't Hoff became interested in studying the phenomenon of polarization of light. At the very beginning of the 19th century, French physicist Jean-Baptiste Biot noticed that the crystalline forms of some chemicals could change the direction of rays of polarized light passing through them.

Observations have shown that some molecules (called optical isomers) rotate the plane of light in the opposite direction to that in which other molecules rotate it, although both are the same type of molecules and consist of the same number of atoms.

In an effort to explain the cause of this phenomenon, Louis Pasteur hypothesized back in 1848 that such molecules are mirror images of each other and that the atoms in them are located in three dimensions. Many scientists disagreed with Pasteur, considering his hypothesis too fantastic. Jacob Van't Hoff decided to check it out.

In 1874, a few months before defending his dissertation, the young scientist published a short article in which he not only substantiated the validity of Pasteur’s theory, but also proposed a refined version of it.

Jacob van't Hoff proposed that the optical activity of organic compounds is associated with an asymmetric molecular structure, with the carbon atom located at the center of the tetrahedron, and at its four corners there are atoms or groups of atoms that differ from each other. Thus, the interchange of atoms or groups of atoms located in the corners of the tetrahedron can lead to the appearance of molecules that are identical in chemical composition, but are mirror images of each other in structure. This explains the differences in their optical properties.

At first, no one paid attention to this article. The disappointment was so great that Van't Hoff even wanted to give up defending his dissertation.

However, just two months later, a similar work by Van’t Hoff’s acquaintance at the University of Paris, J. Le Bel, was published in France. Independently of Van't Hoff, he came to the same conclusions. Obtaining the same results gave Jacob van't Hoff confidence in his abilities, and he resumed his research.

The experiments carried out not only confirmed the correctness of his conclusions, but also made it possible to construct an integral concept of polarization, called the Van't Hoff-Le Bel theory. But convincing scientists of its correctness turned out to be difficult.

After reading the article by Jacob Hendrik van't Hoff, the famous German chemist Hermann Kolbe called it "fantastic nonsense, completely devoid of any factual basis and completely incomprehensible to a serious researcher."

As a result, Van't Hoff, who was always sensitive to any criticism, did not dare to submit it as a doctoral dissertation. He put aside his research on polarization and wrote a dissertation on cyanoacetic and malonic acids, for which he received a doctorate in chemistry in 1874.

The scientist’s discovery was recognized only two years later. It was then that Jacob van't Hoff's work was translated into French and German. Scientists began to repeat his experiments and one after another recognized the correctness of the theory. Over time, it formed the basis of modern stereochemistry - a field of chemistry that studies the spatial structure of molecules.

The development of Jacob Hendrik Van't Hoff's scientific career was slow. At first he had to give private lessons in chemistry and physics, and only in 1876 did he receive a position as lecturer in physics at the Royal Veterinary School in Utrecht.

The following year, the scientist becomes a lecturer (and later professor) of theoretical and physical chemistry at the University of Amsterdam. Here, for the next 18 years, Van't Hoff gave five lectures every week on organic chemistry and one lecture on mineralogy, crystallography, geology and paleontology, and also directed a chemical laboratory.

Unlike most chemists of his time, Jacob van't Hoff had a thorough mathematical background. It was useful to the scientist when he took on the difficult task of studying the rates of reactions and the conditions affecting chemical equilibrium.

As a result of the work done, the scientist classified chemical reactions depending on the number of molecules involved in them as monomolecular, bimolecular and multimolecular, and also determined the order of chemical reactions for many compounds.

Jacob Hendrik van't Hoff was the first chemist to apply the principles of thermodynamics to this science. This technique made it possible to explain the reason for the mobile equilibrium that arises as a result of temperature changes. At the same time, he introduced the now generally accepted designation for the reversibility of a reaction with two arrows pointing in opposite directions. Van't Hoff presented the results of his research in the book “Essays on Chemical Dynamics,” published in 1884.

In 1811, the Italian physicist Amedeo Avogadro found that equal volumes of any gases at the same temperature and pressure contain the same number of molecules. Van Toff experimentally tested this law and came to the conclusion that it is also valid for dilute solutions. The discovery he made was very important, since all chemical reactions and exchange reactions within living beings occur in solutions.

Conducting experiments, the scientist established some regularities characteristic of osmotic pressure. It turned out that it can be used to characterize the behavior of two different solutions located on both sides of the membrane, tending to equalize the concentration. The scientist also found that dilute solutions also obey the theory of electrolytic dissociation.

In 1878, Jacob van't Hoff married the daughter of a Rotterdam merchant, Johanna Francine Mees. They had two daughters and two sons.

Van't Hoff's fame grew, and many universities offered him a professorship. Now the scientist could choose the most convenient and prestigious place of work. But he refused to leave Holland. As a token of gratitude, the leadership of the University of Amsterdam allocated funds to build a new chemical laboratory for it.

But after a few years, Jacob van't Hoff realized that lectures and administrative duties interfered with full-fledged scientific work. Therefore, he accepted the offer of the University of Berlin and took the position of professor of experimental physics.

However, soon, due to numerous requests from students, he had to resume lecturing. He usually devoted one day a week to lecturing work, and worked all other days in a specially equipped laboratory. Although Van't Hoff was not a brilliant lecturer, his classes attracted crowds of students and young scientists from all over Europe. After all, the scientist’s lectures always contained new ideas and information for scientific research.

In Berlin, Jacob Hendrik van't Hoff began to apply physical chemistry to solve geological problems. He used his technique, for example, in the analysis of ocean salt deposits in Stasfurt.

Studying the processes of their formation, the scientist began to study the problems of biochemistry, in particular, the study of enzymes that served as catalysts for chemical changes necessary for the activity of living organisms.

In his free time, Van't Hoff gave preference to his first hobbies, being interested in poetry and philosophy. The only type of recreation for him was communication with nature: every weekend the scientist tried to get out of the city.

In 1901, Jacob Hendrik van't Hoff became the first ever winner of the Nobel Prize in Chemistry, which was awarded to him "in recognition of the enormous importance of his discovery of the laws of chemical dynamics and osmotic pressure in solutions."

Now we can say that the ideas of Jacob Van't Hoff determined the development of this science for many years to come. Perhaps he would have enriched chemistry with new discoveries, but he unexpectedly fell ill with tuberculosis and died in a hospital in a suburb of Berlin.

van't Hoff

(1852- 1911)

Dutch chemist, one of the founders of the physical theory of chemistry and stereochemistry, Jacob van't Hoff was born on August 30, 1852 in Rotterdam in the family of a doctor.
In 1869 Van't Hoff graduated from high school. And although he dreamed of a career as a chemist since childhood, due to the wishes of his parents, he began to study engineering and even worked for some time at a sugar factory.
In 1871 Van't Hoff entered the Faculty of Science and Mathematics at Leiden University, then moved to the University of Bonn to study chemistry. Van't Hoff improved his knowledge in Paris, after some time he returned to the Netherlands and in 1874. He defended his doctorate in chemistry at Utrecht University.
The development of Jacob's scientific career proceeded very slowly, although it was he who was the first (in 1874-1875) to develop the theory of the spatial arrangement of atoms in the molecules of organic compounds, which soon became the basis of modern stereochemistry. Only in 1876. He took up a position as lecturer in physics at the Royal Veterinary School in Utrecht. In 1878 van't Hoff becomes professor of theoretical and physical chemistry at the University of Amsterdam. In the same year, Jacob Van't Hoff married the daughter of a Rotterdam merchant, Johanna Francine Mees. This happy married couple had two daughters and two sons.
In 1896, van't Hoff moved to the post of professor of experimental physics at the University of Berlin, where he had at his disposal a fully equipped laboratory, and at the same time the opportunity to engage in research activities.
As a result of his research, Van't Hoff derived one of the basic equations of thermodynamics - the isochore equation, as well as a formula for the dependence of the chemical method on the equilibrium constant of the chemical reaction at a constant temperature, that is, the isotherm equation. He developed the theory of dilute solutions, based on the analogy between substances in gas-like and soluble states, extended the law of ideal gases to dilute solutions and derived the law of osmotic pressure (van't Hoff's law). In 1890 he introduced the concept of solid solutions, using his ideas for solids.
In 1901, Van't Hoff became the first Nobel Prize laureate in chemistry in recognition of the enormous importance of his discovery of the law of osmotic pressure in solutions.
In addition to the Nobel Prize, van't Hoff was awarded medals by scientific societies of different countries, was a member of the European and American chemical and science academies, and was awarded a degree at the universities of Great Britain and America.