Final answer:
Propane combustion in a bomb calorimeter is a constant-volume, exothermic process in which the heat released by the reaction raises the temperature of water in the calorimeter, allowing the energy change to be calculated.
Step-by-step explanation:
The combustion of propane inside a bomb calorimeter is an example of a constant-volume calorimetry process. This technique is particularly suitable for combustion reactions and those involving gaseous reactants, since it allows for the measurement of heat released or absorbed under conditions of constant volume. During combustion, propane reacts with oxygen to generate carbon dioxide, water, and a significant amount of heat, which is an indication of an exothermic reaction. Specifically, the heat of combustion of propane is a crucial thermal value used to understand how much energy is produced during the reaction.
In a bomb calorimeter, the gas-tight steel "bomb" containing the propane reactant is filled with excess oxygen and then submerged in water and insulated. An electric current is passed through the mixture to initiate the reaction. As the combustion occurs, the heat released raises the temperature of the water and the calorimeter, and this temperature change can be used to calculate the energy change during the reaction, provided the heat capacity of the bomb and the mass of water are known. Since the volume is held constant, the heat measured corresponds to the internal energy change of the reaction.