Question

In a chemical reaction that takes place at a fixed pressure and volume, the enthalpy change (ΔH) is –585 kJ/mol. Will this reaction result in an increase or a decrease in temperature?

A. There will be an increase in temperature.
B. There will be a decrease in temperature.
C. There will be no change in temperature.
D. There is not enough information to know if the temperature will increase or decrease.

Answer 1

A negative enthalpy change (ΔH) of –585 kJ/mol in a chemical reaction at fixed pressure and volume indicates the reaction is exothermic, resulting in an increase in temperature of the surroundings.

Step-by-step explanation:

In a chemical reaction that takes place at a fixed pressure and volume, where the enthalpy change (ΔH) is –585 kJ/mol, we can determine the impact on temperature. An enthalpy change that is negative, as in this case, means that the reaction is exothermic, and it releases heat to the surroundings. Because heat is being released, there will typically be an increase in temperature of the surroundings. This is shown in the combustion of methane, for example, where the enthalpy change of the reaction is negative and results in a decrease in the system's enthalpy while releasing heat.