Question

How does constant volume/constant pressure affect exothermic enthalpy?

a) Constant volume increases exothermic enthalpy.

b) Constant volume decreases exothermic enthalpy.

c) Constant pressure increases exothermic enthalpy.

d) Constant pressure decreases exothermic enthalpy.

Answer 1

Under constant pressure conditions, the enthalpy change of an exothermic reaction increases.

Step-by-step explanation:

In an exothermic reaction, the system releases heat to the surroundings. The enthalpy change of the reaction, which is the heat exchanged during the reaction, can be affected by constant volume or constant pressure conditions.

For a constant volume condition, the heat released by the reaction will cause an increase in the temperature of the system. This results in an increase in the internal energy and the enthalpy change, making option a) incorrect.

On the other hand, under constant pressure conditions, the heat released by the reaction can cause an increase in the temperature as well as an expansion of the system, which leads to an increase in its volume. As a result, the increase in the internal energy and enthalpy change will be lesser compared to the constant volume condition. Therefore, option c) is the correct answer choice.