Question

If the enthalpy value for a reaction is negative, what does that indicate about the reaction? Please explain how you got your answer
A) It’s endothermic and heat is absorbed by the system.
B) It’s exothermic and heat is absorbed by the system.
C) It’s endothermic and heat is released to the surroundings.
D) It’s exothermic and heat is released to the surroundings.

Answer 1

Answer: Option (D) is the correct answer.

Explanation:

When reactants absorb energy in a chemical reaction then products have more energy than the reactants. The value of $\Delta H$ is positive for an endothermic reaction.

Whereas when reactants release energy in a chemical reaction then products have less energy than the reactants. The value of $\Delta H$ is negative for an exothermic reaction.

Thus, we can conclude that if the enthalpy value for a reaction is negative, then it indicates that the reaction is exothermic and heat is released to the surroundings.

Answer 2

The answer is; D

Enthalpy is the system’s internal energy ( considering the product of its pressure and volume). When the enthalpy is negative, it means that the products have a lower energy level than the reactants - meaning the system has dispensed some energy into the environment.