If the volume and number of moles of a gas are held constant, increasing the temperature will cause the pressure of the gas to increase. This relationship between temperature and pressure is known as Charles's law or Gay-Lussac's law.

According to Charles's law, the pressure of a gas is directly proportional to its temperature, assuming that the volume and the number of moles remain constant. This means that as the temperature increases, the pressure of the gas also increases, and vice versa.

Mathematically, Charles's law can be expressed as:

P₁/T₁ = P₂/T₂

Where:

P₁ and P₂ are the initial and final pressures of the gas

T₁ and T₂ are the initial and final temperatures of the gas

This equation shows that the ratio of the pressure and temperature of a gas remains constant when the volume and the number of moles are held constant.