Heat capacity is heat energy per unit temperature change

Steps:

• Define heat capacity as the heat (Q) needed to raise an object's temperature by 1°C (ΔT = 1°C).
• Recognize Q is measured in joules (J).
• Note ΔT is in degrees Celsius (°C).
• Derive unit from formula C = Q / ΔT, yielding J/°C.

Why C is correct:

• Heat capacity formula C = Q / ΔT directly gives units of J/°C, as it quantifies total heat for a 1°C rise in the entire object.

Why the others are wrong:

• A: J measures energy alone, ignoring temperature change.
• B: J/g measures energy per gram but omits temperature, incomplete for capacity.
• D: J/(g °C) is the unit for specific heat capacity, per unit mass, not total capacity.

Final answer: C