12·0 1·0 M 6·67 20 n ÷ smallest 6·67 6·67 simplest ratio 1 3 empirical formula: CH3 (b) molecular formula = = 2 × CH3 = C2H6 (a) nitrogen oxygen 10 % 30·3 69·7 14·0 16·0 M 2·16 4·36 n ÷ smallest 2·16 2·16 simplest ratio 1 2 empirical formula: NO2 (b) molecular formula = = 2 × NO2 = N2O4 11 (a) carbon hydrogen oxygen % 40·92 4·58 54·50 12·0 1·0 16·0 M 3·41 4·58 3·41 n ÷ smallest 3·41 3·41 3·41 × 3 1 1·34 (1⅓) 1 simplest ratio 3 4 3 empirical formula: C3H4O3 (b) molecular formula = = 2 × C3H4O3 = C6H8O6 12 (a) carbon hydrogen oxygen % 26·67 2·22 71·11 12·0 1·0 16·0 M 2·22 2·22 4·44 n ÷ smallest 2·22 2·22 2·22 simplest ratio 1 1 2 empirical formula: CHO2 (b) molecular formula = = 2 × CHO2 = C2H2O4 (a) = = = 0·01425 mol 13 n(Pb) (b) = sulfide) = 3·42 2·95 = 0·47 g m(S) m(lead m(lead) – − = = = 0·0146 mol n(S)
M 12·0 1·0 n 6·67 20 ÷ smallest 6·67 6·67 simplest ratio 1 3 empirical formula: CH3 (b) molecular formula = = 2 × CH3 = C2H6 10 (a) nitrogen oxygen % 30·3 69·7 M 14·0 16·0 n 2·16 4·36 ÷ smallest 2·16 2·16 simplest ratio 1 2 empirical formula: NO2 (b) molecular formula = = 2 × NO2 = N2O4 11 (a) carbon hydrogen oxygen % 40·92 4·58 54·50 M 12·0 1·0 16·0 n 3·41 4·58 3·41 ÷ smallest 3·41 3·41 3·41 × 3 1 1·34 (1⅓) 1 simplest ratio 3 4 3 empirical formula: C3H4O3 (b) molecular formula = = 2 × C3H4O3 = C6H8O6 12 (a) carbon hydrogen oxygen % 26·67 2·22 71·11 M 12·0 1·0 16·0 n 2·22 2·22 4·44 ÷ smallest 2·22 2·22 2·22 simplest ratio 1 1 2 empirical formula: CHO2 (b) molecular formula = = 2 × CHO2 = C2H2O4 13 (a) n(Pb) = = = 0·01425 mol (b) m(S) = m(lead sulfide) – m(lead) = 3·42 − 2·95 = 0·47 g n(S) = = = 0·0146 mol
empirical_and_molecular_formulae_with_answers.docx