Question

A gas occupied 360 cm³ at 87°C and 380 mm Hg pressure. If the mass of gas is 0.546 g, find its relative molecular mass.

Answer 1

Reduce the volume to NTP conditions,

`"V" xx 760/273 = (360 xx 380)/360`

or, V = `(360 xx 380 xx 273)/(760 xx 360)`

 = 136.5 cm³

136.5 cm³ of the gas weight = 0.546

∴ 22400 cm³ of the gas weight = `0.546/136.5 xx 89.6` a.m.u

∴ Relative molecular mass = 89.6 a.m.u