Honors Chemistry 2016-2017 WS H.1 Hess’ Law 1. Calculate the change in enthalpy for each of the following reactions: A. 2 NO2(g) N2O4(g) → N2(g) + 2 O2(g) 2 NO2(g) = 67.8 kJ → H N2(g) + 2 O2(g) N2O4(g) = 9.67 kJ → H B. C(s) + 2 H2(g) CH4(g) → C(s) + O2(g) CO2(g) = -393.5 kJ → H 2 H2(g) + O2(g) 2 H2O(l) H = -571.66 kJ → CO2(g) + 2 H2O(l) CH4(g) + 2 O2(g) = 890.37 kJ H → C. Sn (s) + 2 Cl2 (g) SnCl4 (l) → Sn (s) + Cl2(g) SnCl2(s) = -325 kJ H → SnCl2 (s) + Cl2 (g) SnCl4 (l) = -186 kJ H → D. Mn (s) + 02 (g) MnO2 (s) → MnO2 (s) + Mn (s) 2 MnO (s) = -240 kJ H → 2 MnO2 (s) 2 MnO (s) + 02 (g) = +264 kJ H → E. SnO2 (s) + 2H2 (g) Sn (s) + 2 H20 (l) → Sn (s) + 02 (g) SnO2 (s) H = -580.7 kJ → H2 (g) + 1/2 02 (g) H20 (l) = -285.8 kJ H → 15
Honors Chemistry 2016-2017 WS H.1 Hess’ Law 1. Calculate the change in enthalpy for each of the following reactions: A. 2 NO2(g) → N2O4(g) N2(g) + 2 O2(g) → 2 NO2(g) H = 67.8 kJ N2(g) + 2 O2(g) → N2O4(g) H = 9.67 kJ B. C(s) + 2 H2(g) → CH4(g) C(s) + O2(g) → CO2(g) H = -393.5 kJ 2 H2(g) + O2(g) → 2 H2O(l) H = -571.66 kJ CO2(g) + 2 H2O(l) → CH4(g) + 2 O2(g) H = 890.37 kJ C. Sn (s) + 2 Cl2 (g) → SnCl4 (l) Sn (s) + Cl2(g) → SnCl2(s) H = -325 kJ SnCl2 (s) + Cl2 (g) → SnCl4 (l) H = -186 kJ D. Mn (s) + 02 (g) → MnO2 (s) MnO2 (s) + Mn (s) → 2 MnO (s) H = -240 kJ 2 MnO2 (s) → 2 MnO (s) + 02 (g) H = +264 kJ E. SnO2 (s) + 2H2 (g) → Sn (s) + 2 H20 (l) Sn (s) + 02 (g) → SnO2 (s) H = -580.7 kJ H2 (g) + 1/2 02 (g) → H20 (l) H = -285.8 kJ 15
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