Commemorating Jacobus Henricus van't Hoff

Commemorating Jacobus Henricus van't Hoff

Author: ChemViews

Jacobus Henricus van’t Hoff (30 August 1852 – 1 March 1911) was a Dutch physical and organic chemist and the first winner of the Nobel Prize in chemistry.

His work on thermodynamic equilibria in gases was put in a general form by Le Chatelier, who extended the principle, and is now known as the van’t Hoff-Le Chatelier principle.

Van’t Hoff equation (above) relates the change in temperature (T) to the change in the equilibrium constant (K) given the standard enthalpy change (ΔHƟ) for a process.

Van’t Hoff also demonstrated that the thermodynamic laws are not only valid for gases, but also for dilute solutions. In L’Équilibre chimique dans les Systèmes gazeux ou dissous à I’État dilué (Chemical equilibria in gaseous systems or strongly diluted solutions), he demonstrated that the osmotic pressure in solutions can be represented by a formula which only deviates from the ideal gas law by a coefficient i, now known as the van’t Hoff factor. The equation he derived, Π = iMRT, gives the pressure on one side of a membrane Π, from the molarity of the solution, M, the thermodynamic (absolute) temperature, T, and the gas constant, R. Van’t Hoff determined i to be the ratio between the actual concentration of particles produced when the substance is dissolved, and the concentration of a substance as calculated from its mass.
For this work he was awarded the Nobel Prize.

Van’t Hoff also made significant contributions to the field of organic chemistry: In a 12-page booklet, he described for the first time the idea of a tetrahedral, asymmetric carbon atom, which explained the occurrence of numerous isomers, inexplicable by means of the then current structural formulae. And so the concept of stereochemistry was born.

Van’t Hoff was a professor of chemistry, mineralogy, and geology at the University of Amsterdam, The Netherlands, for 18 years before moving to University of Berlin, Germany, in 1896. He died from tuberculosis on March 1, 1911, in Steglitz near Berlin.

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