The dissolution of barium hydroxide in water is an exothermic process. Which statement is correct?
A) The enthalpy of solid barium hydroxide plus pure water is less than that of the solution, at the same temperature.
B) The enthalpy of solid barium hydroxide plus pure water is greater than that of the solution, at the same temperature.
C) The enthalpy of solid barium hydroxide plus pure water is the same as that of the solution, at the same temperature.
D) The temperature of the solution is lower than of the barium hydroxide and water before mixing.
E) When barium hydroxide dissolves in water, the system does work on the surroundings.

Question

Quizplus · Accepted Answer

In an exothermic process, the enthalpy of the products is lower than that of the reactants. Therefore, the enthalpy of solid barium hydroxide plus pure water is greater than that of the solution, at the same temperature. Option A is incorrect because the enthalpy of the products is lower than that of the reactants in an exothermic process. Option C is also incorrect because the enthalpy changes during the dissolution process due to the release of heat. Option D is incorrect because the temperature of the solution is higher than that of the individual components before mixing, as heat is released. Option E is incorrect because the process of barium hydroxide dissolving in water is not a work process, but rather a heat releasing process.

The Dissolution of Barium Hydroxide in Water Is an Exothermic