Imagine a reaction that results in a change in both volume and temperature,as shown in the diagram below.What is the sign of the work being done,and what is the sign of the enthalpy change involved in this reaction?

Question

Quizplus · Accepted Answer

Since the volume is decreasing and the temperature is increasing, the work done on the system is negative (w = -). The enthalpy change can be determined using the equation ΔH = q + w, where q is the heat absorbed or released by the system. Since the temperature is increasing, the reaction is likely exothermic and releasing heat (q < 0). Therefore, in order for ΔH to be positive, the work done must be negative to compensate for the negative q value: ΔH = q + w = (negative) + (negative) = positive. Therefore, the sign of ΔH is positive, giving us choice C as the correct answer.

Imagine a Reaction That Results in a Change in Both