Is it true that rate constants are independent of concentration but dependent on temperature? Can you prove it?

1 Answer
Oct 2, 2017

For any rate law

#r(t) = k[A]^m[B]^n#

for the reaction

#A + B -> C + D#,

the rate constant is a constant with respect to concentration but not temperature. It is the rate itself that changes when concentration changes, and as time passes.

#k# is the same for the same reaction at the same temperature, and does not vary no matter what concentrations you use as long as the temperature is the same and all the trials are perfect.

As for why, well, any kinetics experiment would prove that is the case.

  • Here is an answer that shows the rate constant is part of a straight-line slope. If the slope was not a straight line, #k# would not be a constant with respect to concentration and time.
  • This answer repeatedly shows that we get the same #k# for each trial in which the concentrations are varied.

It's something you have to accept, because if you choose to solve for the rate constant using three kinetics trials at the same temperature and different reactant concentrations, you'll get the same thing.