In the expression Q = CpmΔt, the term Cpm represents what physical quantity?

• A. Heat capacity
• B. Specific heat capacity
• C. Mass
• D. Temperature

Answer: (A)

Heat transfer depends on how much energy the system can store for a given temperature rise. In this equation, the factor that multiplies the temperature change is the system’s heat capacity, which is the total amount of energy needed to raise the temperature of the object by one kelvin. This quantity is effectively mass times the specific heat capacity (C = m c_p), so it has units of energy per temperature (J/K). That’s why Cpm represents heat capacity: it converts a temperature change into the corresponding amount of heat. If you tried to read it as mass or temperature alone, the units wouldn’t line up to give energy. Specific heat capacity would appear with mass separately in a form like Q = m c_p ΔT, whereas heat capacity combines them into a single factor that directly multiplies ΔT.