Heat Capacity Units (8.43)

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Hannah Chew 2A
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Heat Capacity Units (8.43)

Postby Hannah Chew 2A » Sun Jan 21, 2018 12:27 pm

Hi, I am confused about the heat capacity units in 8.43. The book says that the heat capacity for a solid is 30 J/mol and for a liquid, it is 60J/mol. What does "J/mol" exactly mean, and what does it say about the temperature? I thought that heat capacity was J/ unit of temperature, so why is this unit different?

I understand that enthalpy of vaporization and fusion are kj/mol, which tells us how much energy is needed to melt and vaporize a mol of said substance, but what about just "regular" heat capacity?

Mike Vinci 2B
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Re: Heat Capacity Units (8.43)

Postby Mike Vinci 2B » Sun Jan 21, 2018 1:39 pm

What's going on Hannah! Molar specific heat is usually shown in Joules per mol or KJ per mole depending on how you want to express it. It represents the amount of heat needed (in Joules or KJ) to raise the temperature of 1 mole of something, by 1 Kelvin. I remember reading that this idea might depend on the presence of phase changes, where you can only use it given that there are no phase changes taking place. However, I'd be interested for others feedback.

Hannah Chew 2A
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Joined: Fri Sep 29, 2017 7:05 am
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Re: Heat Capacity Units (8.43)

Postby Hannah Chew 2A » Sun Jan 21, 2018 4:10 pm

Isn't molar heat capacity J/Kmol ? In this problem, why doesn't the Kelvin appear?


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