a. What is measured by the heat of reaction?

The heat of reaction, also known as enthalpy change, refers to the amount of heat absorbed or released during a chemical reaction at constant pressure. It indicates whether a reaction is exothermic (releases heat) or endothermic (absorbs heat). This measurement is crucial for understanding the energy dynamics of chemical processes.

Enthalpy is a thermodynamic property that represents the total heat content of a system. It is defined as the sum of the internal energy and the product of pressure and volume. Changes in enthalpy during a reaction provide insight into the energy changes that occur, which is essential for calculating the heat of reaction.

Calorimetry is the science of measuring the heat of chemical reactions or physical changes. It involves using a calorimeter, an instrument that can measure the heat transfer associated with a reaction. By determining the heat exchanged, calorimetry allows chemists to quantify the heat of reaction and understand the energy changes involved.