JAMB - Chemistry (2005 - No. 35)

The density of a certain gas is 1.98gdm\(^{-3}\) at s.t.p. What is the molecular mass of the gas?

44.0 g

54.0 g

26.0 g

31.0 g

Density = \(\frac{mass}{volume}\)

Recall that the molar volume of gases at s.t.p = 22.4 dm\(^3\)
∴ 1.98 = \(\frac{mass}{22.4}\)
Mass = 1.98 x 22.4

Molecular mass = 44.35g