Gay-Lussac's Law Calculator

Heat and Pressure: A Guide to Gay-Lussac's Law

Gay-Lussac's Law is a gas law that describes the direct relationship between the pressure and the absolute temperature of a gas, provided the volume and the amount of gas are held constant. Formulated by the French chemist Joseph Louis Gay-Lussac in the early 19th century, the law states that the pressure of a fixed mass of gas is directly proportional to its absolute temperature. This means that if you heat a gas in a rigid container, its pressure will increase. If you cool it, its pressure will decrease.

A common example is an aerosol can. The warning label on the can advises against incinerating it or storing it in a hot place. This is a direct application of Gay-Lussac's Law. If the can is heated, the gas inside heats up, its molecules move faster and collide more forcefully with the walls of the can, dramatically increasing the pressure. This can cause the can to rupture or explode. This calculator allows you to easily solve for any of the variables in the Gay-Lussac's Law equation, making it a valuable tool for understanding the pressure-temperature relationship in gases.

The Gay-Lussac's Law Formula

The direct relationship between pressure (P) and absolute temperature (T) can be expressed mathematically as:

P₁/T₁ = P₂/T₂

Where:

• P₁ and T₁ are the initial pressure and absolute temperature.
• P₂ and T₂ are the final pressure and absolute temperature.

It is essential that the temperature is expressed in an absolute scale like Kelvin (K). Using Celsius or Fahrenheit will give incorrect results.

Molecular Explanation

From a molecular perspective, temperature is a measure of the average kinetic energy of the gas particles. When you heat a gas in a rigid container, the particles gain energy and move faster. This causes them to collide with the walls of the container more frequently and more forcefully, which we measure as an increase in pressure.