Heat is a form of energy that is either absorbed or released during a chemical reaction. The study of heat and energy associated with a chemical reaction or physical changes is known as thermochemistry. A reaction may be endothermic or exothermic (absorb or release energy in the form of heat). The reaction that absorbs energy is called an endothermic reaction, and the one that releases energy is called an exothermic reaction.

Calorimeter is used to measure heat changes that are carried out in vessels. Two types of calorimeters are used: Coffee cup calorimeter and bomb calorimeter. Some amount of heat is absorbed by the calorimeter during heat changes or reactions which is known as a calorimeter constant or the water equivalent of a calorimeter. First, the specific volume of hot and cold water is measured to estimate the water equivalent. The individual temperatures and temperature of the mixture of hot and cold water are recorded, and then the water equivalent is calculated using the following equation.

Water equivalent of the calorimeter, $$\mathrm W\;=\;{\mathrm m}_1\frac{\left({\mathrm t}_{2\;}-{\mathrm t}_3\right)}{\left({\mathrm t}_3-{\mathrm t}_1\right)}-{\mathrm m}_2$$

Heat is absorbed or evolved when a solute is dissolved in a solvent. Hence, the enthalpy change (∆H) of the system is responsible for the dissolution of a solute in a solvent. If heat is absorbed, ∆H value becomes positive, whereas when the heat is evolved, ∆H value becomes negative.

The enthalpy change per mole of a solute dissolved in a pure solvent at a specified concentration of the solution is known as enthalpy of dissolution.

Watch this video to learn more about chemistry.

Requirements for this Science Experiment

⦁ Calorimeter ⦁ Thermometer ⦁ Wooden Box With a Lid ⦁ Hot Plate ⦁ Stirrer ⦁ Beakers ⦁ Measuring Cylinders