What does the heat capacity of a material indicate?

The heat capacity of a material specifically indicates the amount of heat required to raise the temperature of a given quantity of that material by one degree Celsius. This property provides insights into how a substance responds to heat—essentially reflecting its ability to absorb heat without significantly changing temperature.

Heat capacity is crucial for understanding thermal processes and energy requirements in various contexts, such as during heating, cooling, or phase changes. For instance, substances with high heat capacities need more energy to achieve the same temperature change compared to those with low heat capacities.

The other options address different concepts related to material behavior or reactions. The efficiency of a reaction pertains to how effectively reactants are converted into products, which does not directly relate to heat capacity. The amount of heat required to change a phase involves latent heat, which is a separate consideration from temperature change. The temperature at which a material ignites is defined as its ignition point and is unrelated to how heat influences temperature changes in the substance. Thus, the correct interpretation of heat capacity is the amount of heat necessary to increase the temperature by a specific increment.