Will a reaction be more or less spontaneous at higher temperature?
1 Answer
Nov 28, 2017
It depends...
When someone changes the temperature of a chemical process, as long as it is then held constant at this new temperature, the equation
#DeltaG = DeltaH - TDeltaS#
holds, where:
#DeltaG# is the change in Gibbs' free energy.#DeltaH# is the change in enthalpy.#DeltaS# is the change in entropy.#T# is the temperature in#"K"# .As temperature increases,
#DeltaG# will change depending on the sign of#DeltaS# , which can be positive OR negative.
IF THE CHANGE IN ENTROPY IS POSITIVE
If
#DeltaS > 0# , then as#Tuarr# ,#DeltaG# becomes more negative, since subtracting a#(+) cdot (+)# quantity makes something more negative.
IF THE CHANGE IN ENTROPY IS NEGATIVE
If
#DeltaS < 0# , then as#Tuarr# ,#DeltaG# becomes less negative (more positive), since subtracting a#(+)cdot(-)# quantity makes something more positive.
