Total heat capacity
The total heat capacity, C, of a system is used to correlate the change in heat, ΔH, of a system to the observed change in temperature, ΔT:
ΔH = CΔT
For a constant volume calorimeter, the total heat capacity is the sum of the heat capacity of the calorimeter, ccal, and the specific heat capacity of water, cwater, times the mass of water in the water bath, mwater:
C = ccal + cwater mwater
The heat capacity of the calorimeter itself is usually found experimentally by combusting a sample with a known heat of combustion, and using the observed change in temperature to calculate ccal.
For a constant pressure calorimeter the total heat capacity is given by the specific heat capacity of the solvent (typically water) times the mass of that solvent:
C = csolvent msolvent