1. The problem statement, all variables and given/known data You mix 1 liter of water at 20°C with 1 liter of water at 80°C. Set up an equation to find the change in entropy for one of the volumes of liquid in terms of initial temperature (T1) and the temperature after the two volumes of water mixed (T2) 2. Relevant equations ΔS=∫(dQ/T) from state A to state B 3. The attempt at a solution Honestly I don't even know where to start or if I am using the right formula. I tried imagining a process where the volume of water is increased at constant temperature and then the temperature is increased from T1 to T2. I would be grateful if someone pointed me in the right direction.