Physical Chemistry #26: Homogeneous and Heterogeneous Catalysts on Reaction Rates (Slides & Tasks)

In this lesson we discuss how catalysts can increase the rate of reaction, how to represent this on enthalpy profile diagrams and Boltzmann distributions, how to define heterogeneous and homogeneous catalyst and how enzymes catalyse biochemical reactions. This is lesson twenty six in our physical chemistry series for Unit 8: Reaction kinetics (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum).

LESSON OBJECTIVE: Describe how catalysts increase the rate of reaction and illustrate this on a Boltzmann distribution. Understand the difference between homogeneous and heterogeneous catalysts.

LEARNING OUTCOMES (taken from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum):
8.3 Homogeneous and heterogeneous catalysts including enzymes
a) explain and use the term catalysis

b) explain that catalysts can be homogeneous or heterogeneous

c) (i) explain that, in the presence of a catalyst, a reaction has a different mechanism, i.e. one of lower activation energy
(ii) interpret this catalytic effect in terms of the Boltzmann distribution

d) describe enzymes as biological catalysts (proteins) which may have specificity