A quantity of gas is contained in a sealed container of fixed volume. The temperature of the gas is increased.
State, in terms of molecules, two reasons why the pressure of the gas increases.
1.
2.

If the Kelvin temperature of a gas is increased, the volume of the gas increases. This can be understood by imagining the particles of gas in the container moving with a greater energy when the temperature is increased.

Explanation:

If you heat a gas you give the molecules more energy so they move faster. This means more impacts on the walls of the container and an increase in the pressure. Conversely if you cool the molecules down they will slow and the pressure will be decreased.

To calculate a change in pressure or temperature using Gay Lussac's Law.