1. The problem statement, all variables and given/known data 1kg of silver is heated by a large heat reservoir at 373 K from 273K. Calculate the change of entropy in: a) the silver b) the reservoir c) the universe. 2. Relevant equations ΔS = ∫dQ/T 3. The attempt at a solution calculating the change in the silver first ΔS = ∫dQ/T = C∫dT/T = Cln(T2/T1) = 0.312 This is fine, I understand it. Now I need to work out the entropy change in the large reservoir. Since the change happens spontaneously, it isn't reversible and the entropy of the universe increases. This means that I can't just take the negative of the change in the silver. Since the temperature of the reservoir doesn't change, is there no effective change in the entropy? This obviously shouldn't be the case because it would violate the second law. I'd appreciate any insight that can be offered.