Basic Mechanical Engineering (3110006)

Characteristic gas constant ( $\mathrm{R}$ ) varies gas to gas but universal gas constant ( ${\mathrm{R}}^0$ ) is fixed and its value is $8.314 \mathrm{kJ}/\mathrm{kg} \mathrm{mol} \mathrm{K}$.

Value of gas constant ( $\mathrm{R}$ ) can be determine for any gas by using relation,

$\mathrm{R}=\frac{{\mathrm{R}}^0}{\mathrm{M}}$ 

where, $\mathrm{M}$ = molecular weight of gas and ${\mathrm{R}}^0$ = universal gas constant.

The value of $\mathrm{R}$ for air $0.287 \mathrm{kJ}/\mathrm{kg} \mathrm{K}$