# Reversible process

1. Apr 10, 2007

### daudaudaudau

1. The problem statement, all variables and given/known data

A pot is half filled with water and concealed by a lid so that no vapor can escape. The pot is then heated on a stove so steam is formed inside the pot. Now the heat is turned off and the vapor condenses into water. Explain when the process is reversible/irreversible.

3. The attempt at a solution

From what I understand, they are asking about when the heating of the water is a reversible process, right?

Okay, as far as I know the process is reversible if the entropy is the same before the heating and after the vapor has condensed. So if the pot is perfectly isolated the process is reversible. Otherwise it is not. Is this right?

Last edited: Apr 10, 2007
2. Apr 10, 2007

### FredGarvin

Does it require the input of work to return from point 2 back to point 1? In this case, NO so you have a very good argument for it being reversible.

3. Apr 10, 2007

### daudaudaudau

Does it matter if the pot is insulated during the heating? I'd say no.

What if for example the water starts at 20C, and then heated until some steam is formed. Will it then be reversible? Or must it begin at 100C?