Before we look at the Ideal Gas Equation, let us state the four gas variables and one constant for a better understanding. The four gas variables are: pressure (P), volume (V), number of mole of gas (n), and temperature (T).

The gas constant is a physical constant denoted by R and is expressed in terms of units of energy per temperature increment per mole. It is also known as the ideal gas constant or molar gas constant or universal gas constant.

Individual gas constants for the most common gases. The Universal and Individual Gas Constants are known from the Ideal Gas Law . The Individual Gas Constant depends on the particular gas and is related to the molecular weight of the gas. The value is independent of temperature.

The volume (V) occupied by n moles of any gas has a pressure (P) at temperature (T) in Kelvin. The relationship for these variables, \[P V = n R T\] where R is known as the gas constant, is called the ideal gas law or equation of state. Properties of the gaseous state predicted by the ideal gas law are within 5% for gases under ordinary conditions.

Universal gas constant (R), fundamental physical constant arising in the formulation of the ideal gas law. The constant is the same for all gases, provided that the mass of gas being compared is one mole, or one molecular weight in grams. The value of R is 8.314462618 joules per kelvin per mole.

The gas constant or R is an essential constant in the ideal gas law. Discover the definition and value of the gas constant.

Having developed the ideal gas equation and analyzed experimental results for a variety of gases, we will have found the value of R. It is useful to have R expressed using a number of different energy units.

For example, the ideal gas law states that the pressure, volume, and temperature of a gas are directly proportional to each other, as long as the number of particles and the mass of the gas remain constant.

Ideal gas law, relation between the pressure P, volume V, and temperature T of a gas in the limit of low pressures and high temperatures, such that the molecules of the gas move almost independently of each other.