What is the gas expansion formula and how is it used to calculate the change in volume of a gas when it undergoes expansion?

The gas expansion formula is the ideal gas law, which states that the pressure of a gas times its volume is equal to the number of moles of the gas times the gas constant times its temperature. This formula can be rearranged to calculate the change in volume of a gas when it undergoes expansion by using the initial and final conditions of the gas, such as pressure, volume, and temperature.