Sample of impure magnesium is reacted with dilute sulphuric acid to give the respective salt and hydrogen. If 1 g. of the impure sample gave 298.6 cc. of hydrogen at s.t.p. Calculate the % purity of the sample. [Mg = 24, H = 1].

67.2 litres of H₂ combines with 44.8 litres of N₂ to form NH₃ :

N₂(g) + 3H₂(g) ⟶ 2NH₃(g).

Calculate the vol. of NH₃ produced. What is the substance, if any, that remains in the resultant mixture ?

What volume of ethyne gas at s.t.p. is required to produce 8.4 dm³ of carbon dioxide at s.t.p.?

2C₂H₂ + 5O₂ ⟶ 4CO₂ + 2H₂O

[H = 1, C = 12, O = 16]

If 6 litres of hydrogen and 4 litres of chlorine are mixed and exploded and if water is added to the gases formed, find the volume of the residual gas.