Enthalpies of Formation Quiz

-478.8 kJ/mol

) Consider the following two reactions: A → 2B ΔH°rxn = 456.7 kJ/mol A → C ΔH°rxn = -22.1 kJ/mol Determine the enthalpy change for the process: 2B → C A) -478.8 kJ/mol B) -434.6 kJ/mol C) 434.6 kJ/mol D) 478.8 kJ/mol E) More information is needed to solve the problem.

both Co(s) and H₂ (g)

For the species in the reaction below, ΔH°f is zero for ________. 2Co (s) + H₂ (g) + 8PF₃ (g) → 2HCo(PF₃)₄ (l) A) Co (s) B) H₂ (g) C) PF₃ (g) D) HCo(PF₃)₄ (l) E) both Co(s) and H₂ (g)

Xe (g) + 2F₂ (g) → XeF₄ (g)

For which one of the following equations is ΔH°rxn equal to ΔH°f for the product? A) Xe (g) + 2F₂ (g) → XeF₄ (g) B) CH₄ (g) + 2Cl₂ (g) → CH₂Cl₂ (l) + 2HCl (g) C) N₂ (g) + O₃ (g) → N₂O₃ (g) D) 2CO (g) + O₂ (g) → 2CO₂ (g) E) C (diamond) + O₂ (g) → CO₂ (g)

2C (s, graphite) + 2H₂ (g) → C₂H₄ (g)

For which one of the following reactions is the value of ΔH°rxn equal to ΔH°f for the product? A) 2C (s, graphite) + 2H₂ (g) → C₂H₄ (g) B) N₂ (g) + O₂ (g) → 2NO (g) C) 2H₂ (g) + O₂ (g) → 2H₂O (l) D) 2H₂ (g) + O₂ (g) → 2H₂O (g) E) H₂O (l) + 1/2 O₂ (g) → H₂O₂ (l)

3Mg (s) + N₂ (g) → Mg₃N₂ (s)

For which one of the following reactions is the value of ΔH°rxn equal to ΔH°f for the product? A) 2Ca (s) + O₂ (g) → 2CaO (s) B) C₂H₂ (g) + H₂ (g) → C₂H₄ (g) C) 2C (graphite) + O₂ (g) → 2CO (g) D) 3Mg (s) + N₂ (g) → Mg₃N₂ (s) E) C (diamond) + O₂ (g) → CO₂ (g)

(1/2)N₂ (g) + O₂ (g) → NO₂ (g)

For which one of the following reactions is ΔH°rxn equal to the heat of formation of the product? A) N₂ (g) + 3H₂ (g) → 2NH₃ (g) B) (1/2)N₂ (g) + O₂ (g) → NO₂ (g) C) 6C (s) + 6H (g) → C₆H₆ (l) D) P (g) + 4H (g) + Br (g) → PH₄Br (l) E) 12C (g) + 11H₂ (g) + 11O (g) → C₆H₂₂O₁₁ (g)

-92

Given the data in the table below and ΔH°rxn for the reaction SO₂Cl₂ (g) + 2H₂O (l) → H₂SO₄ (l) + 2HCl (g) ΔH° = -62 kJ ΔH°f of HCl (g) is ________ kJ/mol. A) -184 B) 60 C) -92 D) 30 E) Insufficient data are give

-570.37

Given the data in the table below, ΔH°rxn for the reaction 3 Cl₂ (g) + PH₃ (g) → PCl₃ (g) + 3 HCl (g) is ________ kJ. A) -385.77 B) -570.37 C) 570.37 D) 385.77 E) The ΔH°f of Cl₂ (g) is needed for the calculation.

570.37

Given the data in the table below, ΔH°rxn for the reaction PCl₃ (g) + 3 HCl (g) → 3Cl₂ (g) + PH₃ (g) is ________ kJ. A) -570.37 B) -385.77 C) 570.37 D) 385.77 E) The ΔH°f of Cl₂ (g) is needed for the calculation.

Ni (s)

In the reaction below, ΔH°f is zero for Ni (s) + 2CO (g) + 2PF₃ (g) → Ni(CO)₂(PF₃)₂ (l) A) Ni (s) B) CO (g) C) F₃ (g) D) Ni(CO)₂(PF₃)₂ (l) E) both CO (g) and PF₃ (g)

F₂ (s)

Of the following, ΔH°f is not zero for A) O₂ (g) B) C (graphite) C) N₂ (g) D) F₂ (s) E) Cl₂ (g)

Sc (g)

Of the following, ΔH°f is not zero for A) Sc (g) B) Si (s) C) P₄ (s, white) D) Br₂ (l) E) Ca (s)

1 atm

The standard enthalpy change of a reaction is the enthalpy change when all reactants and products are at ________ pressure and a specific temperature.