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Knowing which one to use

Posted: Fri Feb 08, 2019 1:10 am
by Brandon Mo 4K
How do we tell which heat capacity to use (heat capacity, specific heat capacity, and molar heat capacity)?

Does anyone also know the variables used for them?
In my notes there are C, Cv, Cp, Csp. I am confused which one is which.

Re: Knowing which one to use

Posted: Fri Feb 08, 2019 2:00 am
by Jessica Castro 2H
Heat capacity (C) is simple the heat supplied / change in temp (C = q / delta T). Specific heat capacity (Cs) is the heat capacity at a given mass (Cs = C/m), therefore q = m x Cs x delta T. Molar heat capacity (Cm) is the heat capacity at a given amount of moles (Cm = C/n), therefore q = n x Cm x delta T. Cv is the molar heat capacity at constant volume and Cp is the molar heat capacity at constant pressure.

Re: Knowing which one to use

Posted: Fri Feb 08, 2019 12:09 pm
by Hedi Zappacosta 1E
You just have to read the problem and consider the variables that are being kept constant. If volume is constant, use Cv and if pressure is constant, use Cp and so on. specific heat capacity and molar heat capacity are the same. It should say in the question whether youre dealing with moles or grams.

Re: Knowing which one to use

Posted: Fri Feb 08, 2019 12:43 pm
by Tarika Gujral 1K
Heat capacity (neither specific nor molar) is used if no mass/moles are given.

An example is using a calorimeter calibration.
q = Ccal * delta T
Then plug in Ccal to determine q for a different reaction.