Constant Volume Bomb Calorimeter

Concept Quiz

Constant Volume Calorimetry ($\Delta V = 0$)

A bomb calorimeter is a rigid steel container used to measure the heat of combustion. Because the volume is strictly constant ($dV = 0$), no mechanical work is done ($W = -P \Delta V = 0$). Therefore, according to the First Law of Thermodynamics, all heat released by the reaction ($q_v$) exactly equals the change in Internal Energy ($\Delta U$).

$$ q_v = \Delta U = C_{cal} \cdot \Delta T $$
$q_v$ = Heat transferred at constant volume
$C_{cal}$ = Total Heat Capacity of the Calorimeter (Water + Hardware)
$\Delta T$ = Change in temperature ($T_{final} - T_{initial}$)