# Homework Help: Find the difference in entropy between a cup of water and a cup of ice

1. Feb 11, 2009

### erin88

Find the difference in entropy between a cup of water and a cup of ice for each of these cases:
1. both are at T=0C
2. ice is at T=0C water is at 20C

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If the "water" is at 0C then it is ice right? and the difference in entropy is 0 correct?

For the second part... do you think I am supposed to find the Q for each one? since the equation for Q is Q=cmT I don't think this would make sense because the equation for entropy (S) is S=Q/T. For ice it would be 0/0 and you can't do that....

Do you think maybe he's asking for the change in entropy if you mix the two together?

Thanks.

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EDIT

I just remembered the equation is Q=cmdeltaT

So this must mean that he does want to know the change of entropy in the system if you mix the two together??

Last edited: Feb 11, 2009
2. Feb 11, 2009

We have $$Q = S T$$