1. (a) (i)What volume of oxygen is required to burn completely a mixture of 22.4 dm3of methane and 11.2 dm3 of hydrogen into carbon dioxide and steam? Equations of the reactions are given below (Assume that all volumes are measured at S.T.P ) CH4 + 2O2 → CO2 + 2H2O 2H2 + O2 → 2H2O   2. (ii) The gases hydrogen‚ oxygen, carbon dioxide, sulphur dioxide and chlorine are arranged in order of their increasing relative molecular mass. Given 8g of each gas at STP, which gas will contain the least number of molecules and which gas the most?