Molar heat capacity

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Molar heat capacity

Postby ZoeHahn1J » Thu Jan 11, 2018 10:58 pm

What determines a substance's molar heat capacity? From Cv,m = delta U/delta T, it appears that molar heat capacity would depend on the change in internal energy and temperature of a monatomic gas, but molar heat capacities are independent of temperature, so I'm unsure of what actually determines them. Thanks so much!

Angela G 2K
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Re: Molar heat capacity

Postby Angela G 2K » Thu Jan 11, 2018 11:07 pm

Molar heat capacity is the amount of heat needed to raise one mole of a substance by one degree Kelvin, and is dependent on the intermolecular forces between the particles. For example, a substance with strong intermolecular forces (such as water, which has hydrogen bonds) would have a higher heat capacity than a substance with weaker intermolecular forces.

Elizabeth Ignacio 1C
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Re: Molar heat capacity

Postby Elizabeth Ignacio 1C » Sun Jan 14, 2018 10:49 am

Heat capacity is dependent on temperature, as you mentioned with Cv = ΔU/ΔT (equation for heat capacity at a constant volume).

To find the molar heat capacity at a constant volume, you take Cv and divide it by however many moles of substance you have. You're looking for the heat capacity per unit (mole) of pure substance. Cv,m = Cv /m

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