Which of the following signs on q and w represent a system that is doing work on the surroundings,as well as gaining heat from the surroundings?
A) q = +, w = -
B) q = -, w = +
C) q = +, w = +
D) q = -, w = -
E) None of these represent the system referenced above.

Question

Quizplus · Accepted Answer

If the system is doing work on the surroundings, then work is negative (w < 0) since the system is losing internal energy. If the system is gaining heat from the surroundings, then heat is positive (q > 0) since energy is entering the system. Therefore, the only option where both q and w have opposite signs, indicating that energy is both entering the system as heat and leaving the system as work, is option A: q = +, w = -. This is known as an endothermic process, where energy is entering the system from the surroundings.

Which of the Following Signs on Q and W Represent