How does the ideal gas law describe gas behaviour?

The ideal gas law describes how pressure, volume, temperature and the number of particles in a gas are interrelated.

The ideal gas law is a fundamental principle in the study of physical chemistry. It provides a mathematical relationship between the pressure (P), volume (V), temperature (T) and the number of particles (n) in a gas. This relationship is expressed in the equation PV=nRT, where R is the ideal gas constant.

The law assumes that gases behave ideally, meaning they follow this law at all temperature and pressure conditions. However, real gases only obey this law at high temperature and low pressure. At these conditions, the gas particles have sufficient energy to overcome intermolecular forces and the size of individual gas particles becomes negligible compared to the total volume of the gas.

The ideal gas law is derived from the combination of several simpler gas laws, including Boyle's Law, Charles's Law and Avogadro's Law. Boyle's Law states that the pressure of a gas is inversely proportional to its volume at constant temperature. Charles's Law states that the volume of a gas is directly proportional to its absolute temperature at constant pressure. Avogadro's Law states that the volume of a gas is directly proportional to the number of gas particles at constant temperature and pressure.

In practical terms, the ideal gas law allows us to predict how a gas will behave under different conditions. For example, if we know the initial pressure, volume and temperature of a gas, and we change one of these variables, we can use the ideal gas law to calculate the new state of the gas. This is particularly useful in many scientific and industrial applications, such as predicting the behaviour of gases in chemical reactions, in the atmosphere, in engines, and in many other situations.