Question

1 L of a gas at STP weight 1.964 g. What is vapour density of the gas?

Answer 1

1L of gas at STP contain 1/22.4 moles of the gas. =22(approx.)

Answer 2

1 litre of gas = 1.964 g

We know that at STP 1 mole of gas is equal to 22.4 litre of gas.

hence, molar mass of gas = 22.4x1.964 = 43.9936 ~ 44g

We also know that Molar mass = 2xVapour density

hence VD = molar mass/2 = 44/2 = 22