Question

The masses of equal volumes of a gas and hydrogen are 25.6 g and 0.8 g respectively under same conditions of temperature and pressure. Find the molecular mass of the gas.

Answer 1

Here, pressure, volume & temperature are constant.

$\therefore$ No. of moles are equal. {By ideal gas equation}

$\therefore n_{gas}=n_{H_2}$

$\therefore \frac{25.6}{M_{gas}}=\frac{0.8}{2}$

$\therefore M_{gas}=\frac{25.6\times 2}{0.8}=64g/mol$

$\therefore$ Molecular mass of the gas is $64g/mol$