9.15 Question


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Sophia Kim 1C
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9.15 Question

Postby Sophia Kim 1C » Wed Feb 14, 2018 2:38 am

For question 9.15 the change in entropy for freezing of H20 at 0.00C uses a negative deltaH of fusion in the solution manual but this value is not negative in the chart 8.3. Just to clarify, is it negative here because the reaction is going from liquid to ice so the change in entropy is negative?

Leanne Wong 1H
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Re: 9.15 Question

Postby Leanne Wong 1H » Wed Feb 14, 2018 5:27 am

Yes, it is because you are going from liquid to ice which is the opposite of fusion. You could also think of this in terms of the molecules gaining or losing heat since the molecule is going from liquid to ice, it is losing heat so deltaH would be negative.

Jenny Cheng 2K
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Re: 9.15 Question

Postby Jenny Cheng 2K » Thu Feb 15, 2018 11:40 am

ΔH(reverse process)=-ΔH(forward process), so
ΔH(freezing)=-ΔH(fusion)


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