In chemistry, what does the term "heat energy" refer to?

Heat energy refers to the energy that is transferred between systems or objects with different temperatures (thermal energy) and is central to understanding the nature of chemical reactions. When a chemical reaction occurs, it often involves changes in heat, either absorbing energy from the surroundings (endothermic reactions) or releasing energy to the surroundings (exothermic reactions). This transfer of energy is crucial in determining how reactions proceed and the conditions under which they take place.

The idea of heat energy being the energy transferred during a reaction encompasses both the energy released when bonds are formed and the energy required to break bonds. This is essential in describing the enthalpy change of a reaction, a key concept in thermodynamics.

The other concepts listed – like the energy stored in chemical bonds, which pertains to potential energy; the measure of temperature, which quantifies the thermal kinetic energy of particles; and the energy required to change phases, which relates to latent heat – do not capture the broader transfer of energy that characterizes heat energy in the context of chemical processes. Therefore, the proper understanding of heat energy is well encapsulated by its role in energy transfer during chemical reactions.