The relationship between pressure, volume, temperature, and the number of moles of a gas is precisely defined by a specific mathematical expression. This expression posits that the product of pressure and volume is directly proportional to the product of the number of moles, the ideal gas constant, and the absolute temperature. For instance, if the number of moles and temperature of a gas are known, and its pressure is measured, the expression allows for the calculation of its volume.
The significance of this relationship lies in its ability to predict the behavior of gases under varying conditions. It simplifies calculations involving gas properties, providing a foundational understanding for diverse fields such as chemistry, physics, and engineering. Historically, its development represented a major advance in understanding the nature of gases, leading to numerous technological innovations.