Question #635ea

1 Answer
Jun 29, 2016

It is an equation that relates equilibrium constant to temperature.


Equilibrium constants can change according to temperature. The Van't Hoff equation defines the change in equilibrium constant as a function of temperature. The equation under standard conditions is defined as:

#(d ln K_{eq))/(dT) = (DeltaH)/(RT^2)#

Where #DeltaH# is the standard enthalpy change of the reaction, T is the temperature in Kelvins, R is the gas constant (8.314 j/K/mol), and #K_(eq)# is the equilibrium constant.

One of the main applications of the Van't Hoff equation is to make estimations of the equilibrium constant at a specified reaction temperature. To do this, enthalpy of reaction is assumed to be constant over the temperature range considered. It can be a useful exercise, for example in industrial applications where chemical engineers need to check what improvement in yield can be achieved by raising the reaction temperature of an equilibrium system.