How is heat capacity defined?

Heat capacity is defined as the amount of heat needed to raise the temperature of a substance by 1°C or 1 K. This definition underscores the relationship between heat energy and temperature change in a material. Specifically, heat capacity is a measure of how much heat energy is absorbed or released by a substance for a given temperature change, which is crucial in understanding thermal properties and behaviors of materials.

When measuring heat capacity, it reflects not only the intrinsic properties of the substance but also its mass; therefore, it takes into account how the temperature of the entire object changes with the addition or removal of heat. Some substances will exhibit higher heat capacities, meaning they require more energy to achieve the same temperature increase compared to others. This concept is vital in various applications, such as engineering, environmental science, and calorimetry.

The other options provided describe different thermal or chemical phenomena but do not accurately capture the definition of heat capacity. The total energy required to change states of matter refers to latent heat, while energy changes during a chemical reaction and energy released when forming a bond pertain to different aspects of thermodynamics and chemistry that do not specifically convey the concept of heat capacity.