Question

At STP, the density of a gas (molecular weight
45) is
(a) 2 g/litre (b) 22.4 g/litre
(c) 11.2 g/litre (d) 26.6 g/litre

Answer 1

(a) 2 g/litre

Explanation:

The density of any substance is calculated as Density = mass / volume.

One mole of any gas at STP will occupy a volume of 22.4 L (standard molar volume). Given that the gas has a molecular weight of 45 g/mol.

So the density of the gas will be D = m/V = 45 / 22.4 = 2.0 g/L

Option A is the answer.