Note

It is founded that the value of constant is dependent on the enclosed mass of gas for a given gas and is also found to differ for different gases of 1 unit of mass. However, it is found that if 1 mol. mass ( Mass numerically equivalent in gm to molecular weight, e.g., 2 gm for H ₂, 32 gm for O₂ , 28 gm for N₂ , etc.) of any ideal gas is chosen then the value of the constant is same for all gases. This universal constant (same for all gases) is denoted usually by 'R' and is called the universal gas constant.

The ideal gas equation therefore is normally written as

where n = number of molecules.

The no. of molecules is defined as, the ratio of actual mass of gas M to its molecular weight (M_o)

If m is the mass of each molecule of a given gas and N is the no.of molecules that make up the mass = M; whereas N_o= Avogadro's no. = Number of molecules in 1 mole of the gas (any gas), then M = mN & M_o = mN_o.

Index

12.1 Solids
12.2 Liquids
12.3 Gases
12.4 Gas Laws
12.5 Equation of State :Ideal Gas Equation
12.6 Kinetic Theory of Ideal Gases

Chapter 13