A gas of molar mass M has density rho at pressure P and temperature T. Its compressibility factor is given by

JEE Main levelSingle correct optionDifficulty 2 of 3rg007

A gas of molar mass $M$ has density $ρ$ at pressure $P$ and temperature $T$ . Its compressibility factor is given by

For

n

moles,

Z = P V / n RT

. With

n = m / M

and

ρ = m / V

V / n = M / ρ

, so

Z = \frac{PM}{ρRT}

. A real gas denser than the ideal prediction has

Z

less than 1.