A system is acted on by its surroundings in such a way that it receives 50 J of heat while simultaneously doing 70 J of work. What is its net change in internal energy?

Question

Quizplus · Accepted Answer

According to the first law of thermodynamics, the change in internal energy (ΔU) is given by ΔU = Q - W, where Q is the heat added to the system and W is the work done by the system. Here, Q = 50 J and W = 70 J, so ΔU = 50 J - 70 J = -20 J.

A System Is Acted on by Its Surroundings in Such