Question

How can a calorimeter measure energy\[?\]

Answer 1

Hint: A calorimeter is an object used for the process of measuring the heat of chemical reactions or physical changes as well as heat capacity. The calorimeter basically traps all the heat from a chemical reaction. Also the calorimeter is insulated in order to prevent the transfer of heat between the calorimeter and the surroundings.

Complete step-by-step answer:
Calorimetry is the science of measuring changes in state variables of a body for the purpose of deriving the heat transfer associated with changes of its state due to chemical reactions, physical changes, or phase transitions under specified constraints. A calorimeter is an object used for calorimetry, or the process of measuring the heat of chemical reactions or physical changes as well as heat capacity. A simple calorimeter just consists of a thermometer attached to a metal container full of water suspended above a combustion chamber.

When an exothermic reaction occurs in solution in a calorimeter, the heat produced by the reaction is absorbed by the water, which increases its temperature. Likewise when an endothermic reaction occurs, the heat required is absorbed from the thermal energy of the water, which decreases its temperature.

Multiplying the temperature change by the mass and specific heat capacities of the substances gives a value for the energy given off or absorbed during the reaction. Well-insulated calorimeters are used which prevent the transfer of heat between the calorimeter and its environment, which effectively limits the surroundings to the non-system components of the calorimeter. This enables the accurate determination of the heat involved in chemical processes.

Note: Generally we use simple calorimeters constructed from polystyrene cups, these allow more heat exchange with their surroundings, and therefore produce less accurate energy values. Hence for industry and research a well-insulated, fully enclosed reaction vessel, motorized stirring mechanism, and a more accurate temperature sensor is used in the calorimeter.