Ideal Gas Equation
A gas which strictly obeys gas laws is called as perfect or an ideal gas. The size of the molecule of an ideal gas is zero, i.e., each molecule is a point mass with no dimension. There is no force of attraction or repulsion amongst the molecule of the gas. All real gases are not perfect gases. However, at extremely low pressure and high temperature, gases such as hydrogen, nitrogen, helium, etc., are nearly perfect gases.
The equation which relates pressure (P), volume (V), and temperature (T) of a given state of an ideal gas is known as gas equation.
For 1 mol or N_{A} molecule orM gram or 22.4 liters of gas |
PV = RT |
For N molecules of gas |
PV = NkT |
For n grams of gas |
PV = nrT |
Universal gas constant (R) Dimension
Boltzmanâ€™s constant (k) Dimension [ML^{2}T ^{â€“2}Î¸^{â€“1}]
Specific gas constant (r) Dimension [L^{2}T ^{â€“2}Î¸^{â€“1}]
; Unit:
Since the value of M is different for different gases, hence the value of r will be different for different gases.