Standard enthalpy change of reaction

Question

Assignment:

Question 1. If a system loses 300 kJ of heat at the same time that it is doing 600 kJ of work, what is the change in the internal energy of the system?

Question 2. Which of the following equations represents a reaction that provides the heat of formation of sodium hypochlorite (NaOCl)?

Question 3. The heat of combustion for 1 mole of carbon to carbon dioxide is -410 kJ. How many kJ of heat would be liberated from the complete combustion of 60.0 g of carbon?

Question 4. Given the following data at 1 atm of pressure and 25.0ºC:

DHºformation = +64.4 kJ/mole for Cu²⁺

DHºformation = -152.4 kJ/mole for Zn²⁺

DHºformation = 0 for both Zn and Cu because these are in the most stable state.

Calculate the standard heat of reaction for the following reaction:

Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s)

Question 5. The standard enthalpy of formation of propene, C₃H₆, is +20.6 kJ/mole. Calculate the heat of combustion of one mole of C3H6. The heats of formation of CO₂(g) and H₂O(l) are -394 kJ/mole and -285.8 kJ/mole respectively.-7.53 kJ/mole?

Question 6. The standard enthalpy of formation of propane, C₃H₈, is -103.6 kJ/mole. Calculate the heat of combustion of one mole of C3H8. The heats of formation of CO₂(g) and H₂O(l) are -394 kJ/mole and -285.8 kJ/mole respectively.

Question 7. Using the following information calculate the heat of formation of NF₃.

NH₃(g) + 3 F₂(g) → NF₃(g) + 2 HF(g)

DHº = -604.8 kJ

DHºf NH₃(g) = -46.19 kJ/mole

DHºf HF(g) = -269 kJ/mole

Question 8. Using the following information calculate the heat of formation of Fe₂O₃.

Fe₂O₃(s) + 3 CO(g) → 2 Fe(s) + 3 CO₂(g)

DHº = -24.8 kJ

DHºf CO(g) = -110.5 kJ/mole

DHºf CO₂(g) = -393.5 kJ/mole

Question 9. Using the given standard enthalpies of formation and the heat of reaction, calculate the heat of formation of HNO3(aq).

3 NO₂(g) + H₂O(l) → 2 HNO₃(aq) + NO(g)

DHº = -138.5 kJ

DHºf NO₂(g) = +33.84 kJ/mole

DHºf NO(g) = +90.37 kJ/mole

DHºf H₂O(l) = -285.85 kJ/mole

Question 10. Use the given standard enthalpies of formation to determine the heat of reaction of the following reaction:

Fe₂O₃(s) + 2 H₂(g) → 3 Fe(s) + 3 H₂O(l)

DHºf Fe₂O₃(s) = -822.2 kJ/mole

DHºf H₂O(l) = -285.9 kJ/mole

Question 11. Calculate Hof (kJ) for the following reaction from the listed standard enthalpies of formation:

CO(g) + NH₃(g) → HCN(g) + H₂O(g)

DHºf CO(g) = -110.5 kJ

DHºf NH₃(g) = -46.1 kJ

DHºf HCN(g) = +135.1 kJ

DHºf H₂O(g) = -241.8 kJ

Question 12. Use the given standard enthalpies of formation to determine the heat of reaction of the following reaction:

C₃H₆O(l) + 4 O₂(g) → 3 CO₂(g) + 3 H₂O(l)

DHºf CO₂(g) = -393.5 kJ/mole

DHºf H₂O(l) = -285.8 kJ/mole

DHºf C₃H₆O(l) = -249.5 kJ/mole

Question 13. Calculate the heat of reaction (kJ) using the listed heats of formation:

CH₄(g) + 4 F₂(g) → CF₄(g) + 4 HF(g)

DHºf CH₄ = -74.81 kJ/mole

DHºf CF₄ = -925.0 kJ/mole

DHºf HF = -271.1 kJ/mole

Question 14. Use the given standard enthalpies of formation to determine the heat of reaction of the following reaction:

2 C₃H₆(g) + 9 O₂(g) → 6 CO₂(g) + 6 H₂O(l)

DHºf C₃H₆(g) = +53.5 kJ/mole

DHºf CO₃(g) = -393.5 kJ/mole

DHºf H₂O(l) = -285.9 kJ/mole

Question 15. Use the given standard enthalpies of formation to determine the heat of reaction of the following reaction:

NH₃(g) + 3 F₂(g) → NF₃(g) + 2 HF(g)

DHºf NH₃(g) = -46.19 kJ/mole

DHºf NF₃(g) = -113.0 kJ/mole

DHºf HF(g) = -269.0 kJ/mole