Question

A gas X has a density of 3 g/L at 27°C and 1520 mm Hg pressure. Calculate its gram molecular mass.

Answer 1

Given:

Density, d = 3 g/L

Temperature, T = 27°C = 300 K

Pressure, P = 1520 mm Hg = 2 atm

Using the ideal gas equation:

PM = dRT

Therefore,

M = `(dRT)/P`

Where R = 0.0821 L atm mol⁻¹ K⁻¹.

M = `(3 xx 0.0821 xx 300)/2`

= `73.89/2`

= 36.945

≈ 37 g mol^−1​

The gram molecular mass of gas X is 37 g mol^−1​.