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?

Calculate the volume occupied at S.T.P. by 2 moles of SO₂.

Calculate the number of moles of methane in 0.80 g of methane.

Calculate the weight/mass of :

(a) an atom of oxygen

(b) an atom of hydrogen

(c) a molecule of NH₃

(d) 10²² atoms of carbon

(e) the molecule of oxygen

(f) 0.25 gram atom of calcium