3.1.5 Kinetics
The study of kinetics enables chemists to
determine how a change in conditions affects
the speed of a chemical reaction. Whilst the
reactivity of chemicals is a significant factor in
how fast chemical reactions proceed, there are
variables that can be manipulated in order to
speed them up or slow them down
1.5.1 Collision theory Content
Reactions can only occur when collisions take
place between particles having sufficient energy
This energy is called the activation energy
Students should be able to:
•• define the term activation energy
•• explain why most collisions do not lead to a
reaction
1.5.2 Maxwell–Boltzmann
distribution Content Opportunities for
skills development Maxwell–Boltzmann
distribution of molecular energies in gases
Students should be able to draw and interpret
distribution curves for different temperatures
1.5.3 Effect of temperature on
reaction rate Content Opportunities
for skills Meaning of the term rate of reaction
The qualitative effect of temperature changes on
the rate of reaction
Students should be able to use the Maxwell–
Boltzmann distribution to explain why a small
temperature increase can lead to a large
increase in rate
Students could investigate the effect of
temperature on the rate of reaction of sodium
thiosulfate and hydrochloric acid by an initial
rate method
Students could investigate how knowledge and
understanding of the factors that affect the rate
of chemical reaction have changed methods of
storage and cooking of food
Required practical 3
Investigation of how the rate of a reaction
changes with temperature
1.5.4 Effect of concentration and
pressure Content Opportunities for
skills The qualitative effect of changes in
concentration on collision frequency
The qualitative effect of a change in the pressure
of a gas on collision frequency
Students should be able to explain how a change
in concentration or a change in pressure
