R1.2 Energy cycles in reactions Quiz
Studying this course? Keep your progress in one place.
Pick an answer for each. Quizzes never use energy.
5 questions, one answer each
Each answer is checked as you go, with why.
See all 5 questions
1. ΔHf⦵ values (kJ mol⁻¹): CO₂(g) −394, H₂O(l) −286, CH₄(g) −75. What is ΔH⦵ for CH₄ + 2O₂ → CO₂ + 2H₂O(l)?
- A. −605 kJ
- B. −891 kJ
- C. −966 kJ
- D. −755 kJ
2. Which has a standard enthalpy of formation of zero?
- A. H₂O(l)
- B. Br₂(l)
- C. Br₂(g)
- D. O₃(g)
3. In a Born–Haber cycle for CaO, which step is endothermic?
- A. First electron affinity of O
- B. Second electron affinity of O
- C. Formation of the lattice from gaseous ions
- D. Standard enthalpy of formation of CaO
4. Which compound has the largest lattice enthalpy?
- A. NaCl
- B. KCl
- C. MgO
- D. KBr
5. ΔHc⦵ values (kJ mol⁻¹): C₂H₄ −1411, H₂ −286, C₂H₆ −1560. ΔH⦵ for C₂H₄ + H₂ → C₂H₆?
- A. −137 kJ
- B. +137 kJ
- C. −435 kJ
- D. +435 kJ