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Hess's Law

#### Q. Calculate the standard enthalpy change for the reaction 2HCl(g) + F2(g) → 2HF(ℓ) + Cl2(g) given 4HCl(g) + O2(g) → 2H2O(ℓ) + 2Cl2(g) ΔH° = -202.4 kJ/mol rxn 1/2H2(g) + 1/2F2(g) → HF(ℓ) ΔH° = -600.0 kJ/mol rxn H2(g) + 1/2O2(g) → H2O(ℓ) ΔH° = -285.8 kJ/mol rxn 1. ΔH° = +1116.6 kJ/mol rxn 2. ΔH° = -516.6 kJ/mol rxn 3. ΔH° = +516.6 kJ/mol rxn 4. ΔH° = +1587.2 kJ/mol rxn 5. ΔH° = -1015.4 kJ/mol rxn 6. ΔH° = +1015.4 kJ/mol rxn 7. ΔH° = +1088.2 kJ/mol rxn 8. ΔH° = -1088.2 kJ/mol rxn 9. ΔH° = -1116.6 kJ/mol rxn 10. ΔH° = -1587.2 kJ/mol rxn

Solved • Apr 22, 2020

Hess's Law

#### Q. Calculate the standard reaction enthalpy for the reaction. CH4(g) + H2O(g) → CO(g) + 3H2(g) given 2H2(g) + CO(g) → CO(g) CH3OH(ℓ) ΔH° = -128.3 kJ • mol^-1 2CH4(g) + O2(g) → 2CH3OH(ℓ) ΔH° = -328.1 kJ • mol^-1 2H2(g) + O2(g) → 2H2O(g) ΔH° = -483.6 kJ • mol^-1 1. +216 kJ • mol^-1 2. +206.1 kJ • mol^-1 3. +412.1 kJ • mol^-1 4. +155.5 kJ • mol^-1 5. +42.0 kJ • mol^-1

Solved • Apr 22, 2020

Hess's Law

#### Q. Calculate ΔHrxn for the reaction: CaO (s) + CO2 (g) → CaCO3 (s) Use the following reactions and given ΔH values. Ca (s) + CO2 (g) + ½ O2 (g) → CaCO3 (g) ΔH = -812.8 kJ Ca(s) + ½ O2 (g) → CaO (s) ΔH = -1269.8 kJ. Be sure your answer contains the appropriate number of significant figures, is in units of kJ (but do not include units in you submitted answer), and has the correct sign.

Solved • Apr 20, 2020

Hess's Law

#### Q. Given the following reactions: 2NO(g) N2(g) + O2(g) ΔHo = -180 kJ 2NO(g) + O2(g) 2NO2(g) ΔHo = -112 kJ ∆Ho of the reaction below reaction is; N2(g) + 2O2(g) 2NO2(g) A) 68 kJ B) -68 kJ C)-292kJ D)292kJ

Solved • Apr 12, 2020

Hess's Law

#### Q. Given that S (g) + O2 (g) → SO2 (g) ΔG° = -300.1 kJ 2 S (g) + 3 O2 (g) → 2 SO3 (g) ΔG° = - 742.1 kJ. Calculate ΔG°f of the following reaction: SO2 (g) + ½ O2 (g) → SO3 (g). a. -1042.2 kJ. b. -71.0 kJ. c. + 2.47 kJ. d. + 71.0 kJ. e. + 1042.4 kJ

Solved • Apr 8, 2020

Hess's Law

#### Q. Use Hess’ Law to determine the ΔH ̊f for acetic acid. HC2H3O2(l) + 2O2(g) → 2CO2(g) + 2H2O(l) ΔH ̊ = -875 kJ/mol C(s) + O2(g) → 2CO2(g) ΔH ̊ = -394.51 kJ/mol H2(g) + 0.5O2(g) → H2O(g) ΔH ̊ = -483.6 kJ/mol

Solved • Apr 1, 2020

Hess's Law

#### Q. Use Hess’ Law to determine the ΔH˚for the reaction between solid aluminum and chlorine gas to produce solid aluminum chloride. 2Al(s) + 6HCl(aq) → 2AlCl3(aq) + 3H2(g) ΔH˚ = -1049 kJ/mol HCl(g) → HCl(aq) ΔH˚ = -74.8 kJ/mol H2(g) + Cl2(g) → 2HCl(g) ΔH˚ = -1845 kJ/mol AlCl3(s) →AlCl3(aq) ΔH˚ = -323 kJ/mol

Solved • Mar 31, 2020