The ideal gas law is PV = nRT. This formula states that the pressure (P) times volume (V) equals the number of moles of gas (n) times the ideal gas constant (R) times temperature in Kelvin (T). This equation describes the behavior of gas molecules at most temperatures and pressures.
The ideal gas law synthesized the observations of the scientists Boyle, Charles and Avogadro. Boyle discovered that at a constant temperature, the pressure and volume of a gas are inversely proportional, meaning as one value increases, the other decreases. Charles discovered that at a constant pressure, the volume and temperature of a gas are directly proportional. Finally, Avogadro discovered that at constant pressure and temperature, the volume of a gas is directly proportional to the number of moles present.