Thermochemistry is also important in the field of medicine and pharmacology. The study of thermochemistry is used to determine the enthalpy change of a drug reaction. This is vital in determining the dosage and effectiveness of various drugs, as well as their potential side effects.

Thermochemistry is useful in predicting reactant and product quantities throughout the course of a given reaction. In combination with entropy determinations, it is also used to predict whether a reaction is spontaneous or non-spontaneous, favorable or unfavorable.

The changes could be physical such as melting, and evaporation or could also be chemical such as burning, acid-base neutralisation etc.

• Thermochemistry. –The study of the transfer of heat (thermal energy) in chemical reactions. –Exothermic - transfer of heat from the. system to the surroundings.

Flexi Says: Chemists study thermochemistry to understand the energy changes that occur during chemical reactions. This knowledge is crucial in predicting whether a reaction will occur spontaneously, and it helps in the design of energy-efficient chemical processes and the development of new energy sources.

The three laws of thermochemistry are the law of conservation of energy, the law of conservation of mass, and Hess's law. The law of conservation of energy states that the total energy of a system is conserved.

We define the enthalpy change (ΔH) as the heat of a process when pressure is held constant: The letter H stands for “enthalpy,” a kind of energy, while the Δ implies a change in the quantity. We will always be interested in the change in H, rather than the absolute value of H itself.