When considering gases, the variable, pressure is a very important variable that must be considered especially when you are varying the temperature.  Gas pressure is the result of the collisions of molecules against the walls of their container.  The energy and frequency of the collisions depend on the average of kinetic energy of molecules which depends on temperature. As a result, for a fixed quantity of gas at constant volume, the pressure should be directly proportional to the Kelvin temperature, which depends directly on average kinetic energy.
 
 
 
 

In fact, this prediction does turn out to be correct!!  The scientist who is credited for this relationship is Joseph Gay-Lussac.
 

Gay Lussac's law states that the pressure of a specific mass of gas at constant volume varies directly with the Kelvin temperature.

Therefore, If the temperature of a container is increased, the pressure increases.  If the temperature of a container is decreased, the pressure decreases.

Why is this so?

Suppose the temperature is increased. This means gas molecules will move really really faster and they will hit the container walls more often. This means the gas pressure inside the container will increase, since the volume stays constant.

This makes sense because if you look at the back of an aerosol can,which has a constant volume, you will notice that it contains a warning sign that it should not be exposed to heat.  The reason why there is a warning label on cans that are completely sealed is due to this relationship.  First of all, it is important to notice that an aerosol can works because the can has a specific pressure. If this pressure is increased by adding heat, the gas pressure inside the can will increase.  If it increases too much, it could explode because the pressurepressure cannot stay confined within this space.