Which of the following has a negative value of ΔH?

Question

Which of the following has a negative value of ΔH?

a. The melting of snow

b. The evaporation of ethanol

c. The combustion of gasoline

d. The dissolution of ammonium nitrate in a cold pack

Answer 1

c. Hydrocarbon + oxygen -----> CO₂ + H₂O + buckets of heat. Extremely exothermic (flames, explosion), so delta H is negative.

According to thermodynamics the other processes are endothermic (delta H is positive)