(Wikipedia excerpt: …”…A calorimeter/s (C) is an object used for calorimetry, or the process of measuring the heat of chemical reactions or physical changes as well as heat capacity. Differential scanning (C) , isothermal micro (C), titration (C) and accelerated rate (C) are among the most common types. A simple (C) just consists of a thermometer attached to a metal container full of water suspended above a combustion chamber.
It is one of the measurement devices used in the study of thermodynamics, chemistry, and biochemistry. To find the enthalpy change per mole of a substance A in a reaction between two substances A and B, the substances are separately added to a (C) and the initial and final temperatures (before the reaction has started and after it has finished) are noted.
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. Dividing the energy change by how many moles of A were present gives its enthalpy change of reaction..”…)