Which of the following reactions represents an exothermic reaction?

A. NH3 (g) + 12.0 kcal → ½N2 (g) + 3/2H2 (g)

B. CH4 + 2O2 → CO2 + 2H2O + 212,800 cal

C. C + 2S → CS2, ΔH = 27,550 cal

D. C (graphite) → C (diamond), ΔH = 0.45 kcal

E. 2H2O → 2H2 + O2, ΔH = + 58 kcal

Question

Chemistry

Frances Cummings

21 January, 01:06

Which of the following reactions represents an exothermic reaction?

A. NH3 (g) + 12.0 kcal → ½N2 (g) + 3/2H2 (g)

B. CH4 + 2O2 → CO2 + 2H2O + 212,800 cal

C. C + 2S → CS2, ΔH = 27,550 cal

D. C (graphite) → C (diamond), ΔH = 0.45 kcal

E. 2H2O → 2H2 + O2, ΔH = + 58 kcal

+5

Answers (1)

Know the Answer?

Jamal Vargas · Answer 1

B. CH4 + 2O2 → CO2 + 2H2O + 212,800 cal

Explanation:

Exothermic means that energy is released.

A cannot be the answer since the process takes energy in at a surplus to work.

C and D have positive enthalpies, which indicate an endothermic reaction.

Which of the following reactions represents an exothermic reaction?A. NH3 (g) + 12.0 kcal → ½N2 (g) + 3/2H2 (g)B. CH4 + 2O2 → CO2 + 2H2O + 212,800 calC. C + 2S → CS2, ΔH = 27,550 calD. C (graphite) → C (diamond), ΔH = 0.45 kcalE. 2H2O → 2H2 + O2, ΔH = + 58 kcal

Which of the following reactions represents an exothermic reaction?

A. NH3 (g) + 12.0 kcal → ½N2 (g) + 3/2H2 (g)

B. CH4 + 2O2 → CO2 + 2H2O + 212,800 cal

C. C + 2S → CS2, ΔH = 27,550 cal

D. C (graphite) → C (diamond), ΔH = 0.45 kcal

E. 2H2O → 2H2 + O2, ΔH = + 58 kcal