The mass of 5.6 litres of a certain gas at S.T.P. is 12 g. What is the relative molecular mass or molar mass of the gas?

5.6 litres of gas at S.T.P. has mass = 12 g 22.4 litre (molar volume) has mass = x 22.4 = 48 g

How many grams of H₂O are present in 0.2 mole of it?