When a sample of a gas is heated in a sealed, rigid
container from 200 degree Kelvin to 400 degree Kelvin, the pressure exerted by
the gas is increased by a factor 2. Heating any gas actually increases the
volume of the gas within a container. As the temperature of the gas rises, the
molecules of the gas start moving faster and start striking the walls of the
container in which it is kept with more force. The volume of the container
tries to expand to accommodate the fast colliding molecules of the gas.
