The ideal gas law is a fundamental equation in chemistry and physics that relates the four key properties of a gas: pressure (P), volume (V), temperature (T), and the number of moles (n) of gas. It is commonly written as:

PV = nRT

Here, R is the ideal gas constant, and the equation assumes the gas behaves ideally—meaning the gas particles are point-sized, have no intermolecular forces, and undergo perfectly elastic collisions.

This law allows scientists to:

• Predict how gases respond to changes in temperature, pressure, or volume
• Calculate the amount of gas in a container (in moles)
• Understand gas behavior under different conditions

Though real gases deviate slightly under high pressure or low temperature, the ideal gas law provides an excellent approximation in most everyday situations and is widely used in chemical reactions, engineering, and atmospheric science.