A gas of mass 32 gms has a volume of 20 litres at S.T.P. Calculate the gram mol. weight of the gas.

A gas cylinder contains 12 x 10²⁴ molecules of oxygen gas.

Calculate : the mass of O₂ present in the cylinder.

(ii) the volume of O₂ at S.T.P. present in the cylinder.

[O = 16] Avog. no. is 6 × 10²³

The mass of 11.2 litres of a certain gas at s.t.p. is 24 g. Find the gram molecular mass of the gas.

Calculate :

(i) The number of moles in 12 g. of oxygen gas. [O = 16]

(ii) The weight of 10²² atoms of carbon.

[C = 12, Avogadro's No. = 6 x 10²³]