1. The BOLTzmann distribution curve
C2.2 Rates of Reaction
11 November 2018

2. sTARTER

3. Mark Scheme

4. The Boltzmann distribution
In a gas at a constant temperature there will be a number of molecules moving at different speeds. This means they have different energies.
The Boltzmann distribution shows the distribution of molecules with different kinetic energies in a gas at a constant temperature.
Sketch a graph like the one to the side and we will annotate it’s features.

5. The Boltzmann distribution
How would the curve change if we increased the temperature?
How would the curve change if we introduced a catalyst?

6. Knowledge check
Explain what is meant by the term activation energy. (1 mark)
Describe and explain how the rate of reaction is affected by a decrease in temperature (2 marks)
Sketch a Boltzmann Distribution curver for a volume of gas at temperature, T1. Add a second curve for the distribution at a higher temperature, T2. (2 marks)
Explain how raising the temperature increases the rate of reaction, using your answer to question 3. (2 marks)
Using the Boltzmann distribution, explain how the presence of a catalyst increases the rate of reaction. (2 marks)

7. Knowledge Check
Complete the worksheet questions