## Clarification on Heat Capacities

julia lai 3A
Posts: 11
Joined: Wed Sep 21, 2016 2:55 pm

### Clarification on Heat Capacities

So there's the specific heat capacity (Csp) and the molar heat capacity (Cm). How do we know which one to use for a problem? Or do we only use the specific heat capacity? I didn't really understand the the aspects of volume and pressure regarding it and how they're related.

Lubna_Abdulmajeed_2A
Posts: 21
Joined: Wed Sep 21, 2016 2:59 pm

### Re: Clarification on Heat Capacities

I believe it just depends on what is given in the question. Specific heat capacity is the amount of heat required to change the temperature of one gram of a substance by 1 degree celsius or kelvin; molar heat capacity is the amount of heat required to change the temperature of one MOLE of a substance by 1 degree kelvin or celsius. So it depends on what is given and what is being asked.

Alexandra_Shambayate_2L
Posts: 14
Joined: Wed Sep 21, 2016 2:57 pm

### Re: Clarification on Heat Capacities

Specific heat capacity is the heat required to raise the temperature of 1 gram by 1 degree C, while molar heat capacity is the heat required to raise the temperature of 1 mole by 1 degree C. To figure out when to use which, I think you would just have to see if the question is being asked in grams or moles or if you have to convert somehow. Also at a molar heat capacity of a gas at constant pressure, volume changes, and the system does work when it expands. At a constant volume, pressure changes, however, no work is done because at a fixed volume, the system does not expand or contract. Hope this helps!