A depiction of a van't Hoff equilibrium box, according to American chemist Clayton Gearhart, of the type said to have been used by German physical chemist Walther Nernst in 1893 to calculate the available work A of an isothermal reversible reaction in which reactants entered on the left and products exited on the right, the entire process mediated by moving pistons and semi-permeable membranes. [4] |
reaction → energy → heat → useful work
“When I turned to the history of chemistry in graduate school, it was perhaps inevitable that I should therefore have been drawn to the man who best combined both physical chemistry and stereochemistry in his work, Jacobus van’t Hoff. The beauty of three-dimensional chemical forms and their interactions still intrigues me and occupies my daily research, but the most intense aesthetic experience I have ever had in science (outside of the experience of my own rare illuminations) came when I read van’t Hoff’s original derivations of his equations describing the thermodynamic properties of solutions. I was struck first by the brilliance of the analogy he created between the adiabatic cycle that Clausius had imagined for pistons working on a gas and the equivalent cycle that van’t Hoff mentally devised using pistons working on osmotic pressure by means of semipermeable membranes. Beyond that – far beyond that – was the experience of reading the equations he then derived describing the equivalent of PV = nRT for solutions (van’t Hoff 1887). It was the most brilliant, insightful poem I had ever read!
Van’t Hoff’s poem [“The Role of Osmotic Pressure in the Analogy between Solutions and Gases”, 1887] deriving the laws of solutions wasted not a symbol. Each one made numerous connections to existing principles so that each line became a nexus of meaning. His symbols, like a magic key, opened a door from the mansion of gas thermodynamics onto the vista of an entirely unexpected estate that nature had somehow hidden from everyone else. Order from disorder, sense from confusion, imagination, insight, surprise – van’t Hoff had it all. I suddenly understood a comment that van’t Hoff’s contemporary, Max Planck, had made in his Autobiography, to the effect that he was drawn to science when he encountered the first law of thermodynamics in high school. It appeared to him to be ‘like a sacred commandment […] sublime’ (Planck 1949). I suddenly appreciated viscerally how one could shudder before the majestic beauty of unexpected comprehension (Chandrasekhar 1987).”
A 1928 diagrams of an Equilibrium Boxes from English physical chemist John Butler's Fundamentals of Chemical Thermodynamics, which can be used to deduce the equilibrium constant. [4] |