### Molar or Specific heat

Posted:

**Thu Jan 26, 2017 4:07 pm**How can we know when to use the molar or specific heat capacity? Will only one be given to us?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=77&t=18382

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Posted: **Thu Jan 26, 2017 4:07 pm**

How can we know when to use the molar or specific heat capacity? Will only one be given to us?

Posted: **Thu Jan 26, 2017 6:14 pm**

Usually only one will be given to you, but if there is some ambiguity, You usually can tell by the amount thats given in the problem. (I.E. if they give a smaller amount, use specific heat capacity, or if they give you one mol, it'd be molar heat capacity.

Posted: **Thu Jan 26, 2017 9:09 pm**

Well, there's this thing called the heat capacity, as you know, and we denote it as C.

But when samples get very large, we want to look at more manageable values and that's where the Cs (specific heat capacity) and Cm (molar heat capacity) come into play.

Cs is basically C divided by m, the mass of the sample/calorimeter/etc. So Cs = C/m --> q=m(Cs)(delta T)

Cm is C divided by n, or the number of moles of the sample/calorimeter/etc. So Cm = C/n --> q=n(Cm)(delta T).

So long story short if the problem mentions anything about grams, mass, etc., you'd want to use the specific heat capacity.

If the problem says anything about moles, you'd want to use the molar heat capacity.

This is my current understanding of specific and molar heat capacities. If I am mistaken or misinformed in any way please feel free to correct me, and I will appreciate it very much.

But when samples get very large, we want to look at more manageable values and that's where the Cs (specific heat capacity) and Cm (molar heat capacity) come into play.

Cs is basically C divided by m, the mass of the sample/calorimeter/etc. So Cs = C/m --> q=m(Cs)(delta T)

Cm is C divided by n, or the number of moles of the sample/calorimeter/etc. So Cm = C/n --> q=n(Cm)(delta T).

So long story short if the problem mentions anything about grams, mass, etc., you'd want to use the specific heat capacity.

If the problem says anything about moles, you'd want to use the molar heat capacity.

This is my current understanding of specific and molar heat capacities. If I am mistaken or misinformed in any way please feel free to correct me, and I will appreciate it very much.