University:
Concordia University Wisconsin
Course:
CHEM 1414 | General Chemistry I
Academic year:

2023
Views:

176

Pages:

1
Author:

Alma Stephenson

EXTRA PRACTICE PROBLEMS for HESS’ LAW OF HEAT SUMMATION: 1. Given the following equations and reaction: Ho values, determine the heat of reaction (kJ) at 298 K for the 2 OF2(g) + 2 S(s) →SO2(g) + SF4(g) Ho = -276.6 kJ Ho = -827.5 kJ Ho = -296.9 kJ OF2(g) + H2O(l) → O2(g) + 2 HF(g) SF4(g) + 2 H2O(l) → 4 HF(g) + SO2(g) S(s) + O2(g) → SO2(g) Answer: -319.5 kJ 2. Find the ΔH for the reaction below, given the following reactions and subsequent ΔH values: N2H4(l) + H2(g) → 2NH3(g) N2H4(l) + CH4O(l) → CH2O(g) + N2(g) + 3H2 (g) N2(g) + 3H2(g) → 2NH 3(g) CH4O(l) → CH2O(g) + H 2(g) ΔH = -37 kJ ΔH = -46 kJ ΔH = -65 kJ Answer: -18 kJ 3. Find the ΔH for the reaction below, given the following reactions and subsequent ΔH values: N2(g) + 2O2(g) → 2NO 2(g) N2(g) + 3H2(g) → 2NH3(g) 2NH3(g) + 4H2O(l) → 2NO2(g) + 7H2(g) H2O(l) → H2(g) + 1/2O 2(g) ΔH = -115 kJ ΔH = -142.5 kJ ΔH = -43.7 kJ Answer: -83 kJ 4. Calculate the value of Ho/kJ for the following reaction using the listed thermochemical equations: P4O10(g) + 6 PCl5(g) →10 Cl3PO(g) 1/4 P4(s) + 3/2 Cl2(g) → PCl3(g) P4(s) + 5 O2(g) → P4O10(g) PCl3(g) + Cl2(g) → PCl5(g) PCl3(g) + 1/2 O2(g) → Cl3PO(g) Answer: -610.1 kJ Ho = -306.4 kJ Ho = -2967.3 kJ Ho = -84.2 kJ Ho = -285.7 kJ