Question

1.45 litre of a gas is collected over water at 27°C and
744 mm of Hg. If the gas weighs 1.98 g and vapour
pressure of water at 27°C is 32 mm, what is the
molecular weight of gas?​

Answer 1

w = 1.98g

V = 1.47 litre

T = 303 K

P = 744 - 32 = 712mm = 712760 atm

Since For dry gas , PV=wmRT

=712760×1.47=1.98m×0.0821×303

∴m=35.76g