1. The problem statement, all variables and given/known data See thumbnail 2. Relevant equations 3. The attempt at a solution I'm not having trouble with the first part, just having trouble understanding why dQ is not exact but dS=dQ/T is. At first I was thinking that it had to do with the V in the dT part of the dQ equation because the single V does not account for changes in V, but this part still exists in the entropy equation. Please help me conceptualize what it means to be an exact differential.