Homework Question 4I.1

[Victoria Zheng--2F]

Hello. What method should I use to solve homework question 4I.1, should I be using q/T for temperature of 800K and q/T for temperature of 200K and subtract the the delta S for 800K from the delta S of 200K? What is the reasoning behind this method? Or should I use other methods?

[Goyama_2A]

Yes, you would use that method. The reasoning behind this is that entropy is a state function, so the value is only dependent on its final state rather than the path taken to get there. Because of this, you are able to add together the change in entropy from each step and find the change in entropy of the entire process. The first change in entropy would be that of the heat leaving the first reservoir (resulting in a negative value), and the second change in entropy would be that of the heat entering the second reservoir (resulting in a positive value).

[Morgan Carrington 2H]

Yes, you would use that method. The reasoning behind this is that entropy is a state function, so the value is only dependent on its final state rather than the path taken to get there. Because of this, you are able to add together the change in entropy from each step and find the change in entropy of the entire process. The first change in entropy would be that of the heat leaving the first reservoir (resulting in a negative value), and the second change in entropy would be that of the heat entering the second reservoir (resulting in a positive value).

What role does the mentioning of the reservoir play why this method should be used? I understand that this is the way that it should be solved but II'm not sure how to relate it to the changing of the temperatures of the reservoirs.