hess_law_additional_practice_problems

Hess ’ Law – Additional Practice Problems 1 Find the ΔH for the reaction below, given the following reactions and subsequent ΔH values:answer = 249.8 kJ PCl 5 (g) → PCl 3 (g) + Cl 2 (g) P 4 (s) + 6Cl 2 (g) → 4PCl 3 (g) ΔH = -2439 kJ 4PCl 5 (g) → P 4 (s) + 10Cl 2 (g) ΔH = 34 38 kJ 2 Find the ΔH for the reaction below, given the following reactions and subsequent ΔH 7 Find the ΔH for the reaction below, given the following reactions and subsequent ΔH values:answer = 886 kJ CO 2 (g) → C(s) + O 2 (g) H 2 O(l) → H 2 (g) + 1/2O 2 (g) ΔH = 643 kJ C 2 H 6 (g) → 2C(s) + 3H 2 (g) ΔH = 190.6 kJ 2CO 2 (g) + 3H 2 O(l) → C 2 H 6 (g) + 7/2O 2 (g) ΔH = 3511.1 kJ values: answer = 235 kJ 2CO 2 (g) + H 2 O(g) → C 2 H 2 (g) + 5/2O 2 (g) C 2 H 2 (g) + 2H 2 (g) → C 2 H 6 (g) ΔH =-94.5 kJ H 2 O(g) → H 2 (g) + 1/2O 2 (g) ΔH =71.2 kJ C 2 H 6 (g) + 7/2O 2 (g) → 2CO 2 (g) + 3H 2 O(g) ΔH =-283 kJ 3 Find the ΔH for the reaction below, given the following reactions and subsequent ΔH 8 Find the ΔH for the reaction below, given the following reactions and subsequent ΔH values:answer = -46.2 kJ N 2 H 4 (l) + CH 4 O(l) → CH 2 O(g) + N 2 (g) + 3H 2 (g) 2NH 3 (g) → N 2 H 4 (l) + H 2 (g) ΔH = 22.5 kJ 2NH 3 (g) → N 2 (g) + 3H 2 (g) ΔH = 57.5 kJ CH 2 O(g) + H 2 (g) → CH 4 O(l) ΔH = 81.2 kJ values: answer = -18 kJ N 2 H 4 (l) + H 2 (g) → 2NH 3 (g) N 2 H 4 (l) + CH 4 O(l) → CH 2 O(g) + N 2 (g) + 3H 2 (g) ΔH = -37 kJ N 2 (g) + 3H 2 (g) → 2NH 3 (g) ΔH = -46 kJ CH 4 O(l) → CH 2 O(g) + H 2 (g) ΔH = -65 kJ 4 Find the ΔH for the reaction below, given the following reactions and subsequent ΔH 9 Find the ΔH for the reaction below, given the following reactions and subsequent ΔH values: answer = -230 kJ 1/2H 2 (g) + 1/2Cl 2 (g) → HCl(g) COCl 2 (g) + H 2 O(l) → CH 2 Cl 2 (l) + O 2 (g) ΔH = 47.5 kJ 2HCl(g) + 1/2O 2 (g) → H 2 O(l) + Cl 2 (g) ΔH = 105 kJ CH 2 Cl 2 (l) + H 2 (g) + 3/2O 2 (g) → COCl 2 (g) + 2H 2 O(l) ΔH = -402.5 kJ values: answer = 72 kJ H 2 SO 4 (l) → SO 3 (g) + H 2 O(g) H 2 S(g) + 2O 2 (g) → H 2 SO 4 (l) ΔH = -235.5 kJ H 2 S(g) + 2O 2 (g) → SO 3 (g) + H 2 O(l) ΔH = -207 kJ H 2 O(l) → H 2 O(g) ΔH = 44 kJ 5 Find the ΔH for the reaction below, given the following reactions and subsequent ΔH 10 Find the ΔH for the reaction below, given the following reactions and subsequent ΔH values: answer = -705 kJ C 2 H 2 (g) + 5/2O 2 (g) → 2CO 2 (g) + H 2 O(g) C 2 H 6 (g) → C 2 H 2 (g) + 2H 2 (g) ΔH = 283.5 kJ H 2 (g) + 1/2O 2 (g) → H 2 O(g) ΔH = -213.7 kJ 2CO 2 (g) + 3H 2 O(g) → C 2 H 6 (g) + 7/2O 2 (g) ΔH = 849 kJ values: answer = 204.0 kJ 11 Find the ΔH for the reaction below, given the following reactions and subsequent ΔH 2C 2 H 4 O(l) + 2H 2 O(l) → 2C 2 H 6 O(l) + O 2 (g) values: Answer = -78 kJ C 2 H 6 O(l) + 3O 2 (g) → 2CO 2 (g) + 3H 2 O(l) ΔH = -685.5 kJ HCl(g) + NaNO 2 (s) → HNO 2 (l) + NaCl(s) C 2 H 4 O(l) + 5/2O 2 (g) → 2CO 2 (g) + 2H 2 O(l) ΔH = -583.5 kJ 2NaCl(s) + H 2 O(l) → 2HCl(g) + Na 2 O(s) ΔH = 507 kJ NO(g) + NO 2 (g) + Na 2 O(s) → 2NaNO 2 (s) ΔH = -427 kJ 6 Find the ΔH for the reaction below, given the following reactions and subsequent ΔH NO(g) + NO 2 (g) → N 2 O(g) + O 2 (g) ΔH = -43 kJ values: answer = -83 kJ 2HNO 2 (l) → N 2 O(g) + O 2 (g) + H 2 O(l) ΔH = 34 kJ N 2 (g) + 2O 2 (g) → 2NO 2 (g) N 2 (g) + 3H 2 (g) → 2NH 3 (g) ΔH = -115 kJ 12 Find the ΔH for the reaction below, given the following reactions and subsequent ΔH 2NH 3 (g) + 4H 2 O(l ) → 2NO 2 (g) + 7H 2 (g) ΔH = -142.5 kJ values: Answer = -976.03 kJ H 2 O(l) → H 2 (g) + 1/2O 2 (g) ΔH = -43.7 kJ Zn(s) + 1/8S 8 (s) + 2O 2 (g) → ZnSO 4 (s) Zn(s) + 1/8S 8 (s) → ZnS(s) ΔH = -183.92 kJ 2ZnS(s) + 3O 2 (g) → 2ZnO(s) + 2SO 2 (g) ΔH = -927.54 kJ 2SO 2 (g) + O 2 (g) → 2SO 3 (g) ΔH = -196.04 kJ ZnO(s) + SO 3 (g) → ZnSO 4 (s) ΔH = -230.32 kJ Chemistry 12 – Hess Law Additional Problems