Calculate ΔU of a gas for a process in which the gas absorbs 29 J of heat and does 31 J of work by expanding.
A)2 J
B)60 J
C)-60 J
D)0,because ΔU is a state function
E)-2 J

Question

Quizplus · Accepted Answer

The first law of thermodynamics states that ΔU = Q - W, where ΔU is the change in internal energy of the system, Q is the heat absorbed by the system, and W is the work done on the system. 
Substituting the given values, we get ΔU = 29 J - 31 J = -2 J. 
Therefore, the correct answer is E, -2 J.

Calculate ΔU of a Gas for a Process in Which