Bomb calorimeter and heat capacity of calorimeter

Question

Can anyone describe the process through which we determine the heat capacity of calorimeter, for me?

The formula is $q_{calorimeter} = C_{calorimeter} \times \Delta T$

The heat of bomb calorimeter is shown to be the same as negative heat of reaction. But without mass, their unit would be different, no?

Answer 1

The heat capacity of a calorimeter, $C_{calorimeter}$ is given in units of kJ/°C, with no units of mass included. This is because the calorimeter's mass is a constant and each calorimeter's heat capacity (and mass) is different.

The general procedure that is used to determine the heat capacity of a calorimeter is as follows:

1. Place a carefully measured quantity of a compound whose combustion energy is well known and that is available in a pure form in the bomb, usually benzoic acid.
2. Seal the bomb and add oxygen so that the sample will burn completely.
3. Submerge the bomb and ignite the sample.
4. Measure the temperature change of the water bath in which the bomb is submerged.

Since you know the energy of the reaction and you know the heat energy in the water, you can find the heat energy of the calorimeter.

$\Delta E = q_{water} + q_{calorimeter}$

The heat of the calorimeter is the difference between the energy we know we put into the system through the combustion of our standard and the heat that was measured in the water bath.