Explain the concept of specific heat capacity and provide its units.

• A. The amount of heat required to raise the temperature of 1 g (or 1 kg) of a substance by 1°C; units J/(g·K) or J/(kg·K).
• B. The amount of heat required to raise the temperature of 1 mole of a substance by 1 K; units J/(mol·K).
• C. Heat released during a phase change; units J.
• D. Energy per unit mass without temperature consideration; units J/kg.

Answer: (A)

Specific heat capacity tells you how much heat you must add to a given mass of a substance to raise its temperature by 1 degree. Since a 1 degree temperature change is the same as a 1 K change, the same concept applies for both Celsius and Kelvin scales. The units reflect heat per unit mass per temperature change, so you’ll see J/(g·K) or J/(kg·K). This is an intensive property, meaning it depends on the material and its phase, not on how much material you have. The basic relation q = m c ΔT uses this quantity: the heat added equals mass times the specific heat capacity times the temperature change. For comparison, molar heat capacity uses per mole and has units J/(mol·K). Phase changes behave differently: the temperature stays constant while heat goes into changing the phase, which is latent heat and not described by the specific heat capacity.