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8. Thermochemistry

Hess's Law

8. Thermochemistry

Hess's Law

Multiple Choice
Calculate the∆H_rxn for
Given the following reactions:
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Multiple Choice
Given the following reactions:2S (s) + 3O2 (g) → 2SO3 (g) ΔH = -790 kJS (s) + O2 (g) → SO2 (g) ΔH = -297 kJWhat is the enthalpy change (ΔH) for the reaction in which sulfur dioxide is oxidized to sulfur trioxide: 2SO2 (g) + O2 (g) → 2SO3 (g)?
Open Question
Calculate the enthalpy of the reaction 4B(s) + 3O₂(g) → 2B₂O₃(s)
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Open Question
Consider the reaction H2O(l) → H2O(g), ΔH =44.0 kJ what will ΔH be for the reaction if it is reversed?
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Open Question
Calculate the enthalpy of the reaction 4B(s) + 3O₂(g) → 2B₂O₃(s).
Multiple Choice
Calculate the∆Hrxnfor the following thermochemical equation:
When given the following:

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Multiple Choice
Calculate ΔH⁰ for the process 1/2 N2(g) + 1/2 O2(g) → NO(g) using Hess's Law and the following reactions: 1. N2(g) + 3 H2(g) → 2 NH3(g) ΔH⁰ = -91.8 kJ 2. 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g) ΔH⁰ = -906.2 kJ 3. H2(g) + 1/2 O2(g) → H2O(g) ΔH⁰ = -241.8 kJ
Multiple Choice
Using Hess's Law, calculate the ΔH for the reaction: N2(g) + 2O2(g) ---> 2NO2(g) using the following data:1. 2 NH3(g) + 4 H2O(l) ---> 2 NO2(g) + 7 H2(g) ΔH = −142.4 kJ2. N2(g) + 3H2(g) ---> 2NH3(g) ΔH = −115 kJ3. H2O(l) ---> H2(g) + 1/2 O2(g) ΔH = −43.7 kJ