Question

1. The empirical formula of an unknown substance is HSO4. If the molecular weight of the substance 194 glmol, what is its molecular formula? 2. How many grams of ammonia are produced when 32g of nitrogen react with excess hydrogen? N2 3H23 2NH, 3. The empirical formula of an unknown substance is determined to be CH2. What is its molecular formula if the molecular weight is 84 gmole? 4. Nicotine has an empirical formula of CsHTN and a molecular weight of 162 g/mol. What is its molecular formula? 5. Ethylene glycol has a simplest formula of CH30 and a molecular weight of 62 g/mol What is the molecular formula? 6. Calculate the number of moles of nitrogen that are needed react with 4.9 moles of to hydrogen if the two react directly to produce ammonia. N 3H2 2NH3 7. If sulfur dioxide rertr uith

Answer 1

Molecular formula = (Empirical formulas)n n = M.F.wt/E.F.wt [Because E.F. wt at 1 + 32 + 64 = 97] = 194/97 = 2 Molecular formula = (HSO_4)_2 = H_2S_2O_8 2. N_2 + 3H_2 rightarrow 2NH_3 1 mole of N_2 react with H_2 to form 2 moles of NH_3 28 g of N_2 react with H_2 to form 2 times 17 g of NH_3 32 g of N_2 react with H_2 to form = 2 times 17 times 32/28 = 38.86 g of NH_3 3. Molecular formula = (Empirical formula) n n = M.wt/E.F.wt = 84/14 = 6 Molecular formula = (CH_2)_6 = C_6H_12 4. Molecular formula = (Empirical formula)n n = M.WT/E.F wt = 162/81 = 2 Molecular formula = (C_5H_7N)2 = C_10H_14N_2 \r\n 5. Molecular formula = (Empirical formula) n n = M.wt/E.F.wt = 62/31 = 2 Molecular formula = (CH_3O)_2 = C_2H_6O_2 6. N_2 + 3H_2 rightarrow 2NH_3 3 moles of H_2 react with 1 mole of N_2