Consider 2 beakers each containing 1kg of water. One beaker has initial temperature of 25 degrees celsius and the other at 100 degrees celsius. The beaker are now mixed. Assuming no heat exchanged is involved with the surroundings; Calculate the final temperature of the water and the entropy change in the universe.
In working out, I've managed to determine the final temperature of the water to be $334K$. The entropy change in the universe is approximately $57Jk^-1$.
The question continues:
In a completely separate process, a reversible heat engine using the Carnot cycle is to be operated between 2 beakers of water starting in their initial states of 25 degrees celsius and 100 degrees celsius. The final state will have the beakers at the same temperature at which the engine would have stopped. Again, assuming the whole system is isolated so no heat is exchanged with the surrounding;
What is the change in entropy of the Universe from the initial to the final state?
I understand the keyword here is reversible heat engine in a Carnot cycle
but after an hour, I am unable to get started. Really appreciate if anyone could at least get me moving. Thanks in advance.
Edit: The reason for not posting workings in the first question is because of the irrelevance of the working to the second leg of the question. I'm more interested in concepts for which I must recall or being directed to an approach to get me started.