A system initially has an internal energy U of 504 J. It undergoes a process during which it releases 111 J of heat energy to the surroundings, and does work of 222 J. What is the final energy of the system, in J?
A) 171 J
B) 393 J
C) 504 J
D) 615 J
E) 837 J

Question

Quizplus · Accepted Answer

The final energy of the system can be calculated using the first law of thermodynamics: ΔU = Q - W. Here, ΔU is the change in internal energy, Q is the heat exchanged, and W is the work done by the system. The system releases 111 J of heat (Q = -111 J) and does 222 J of work (W = 222 J). Therefore, ΔU = -111 J - 222 J = -333 J. The final energy is U + ΔU = 504 J - 333 J = 171 J.

A System Initially Has an Internal Energy U of 504