What does specific heat capacity measure?

• A. The energy required to raise the temperature of any mass by 1°C.
• B. The energy required to raise the temperature of 1 kg by 1°C.
• C. The energy released when a substance freezes.
• D. The energy transferred per mole of substance.

Answer: (B)

The idea being tested is that specific heat capacity tells you how much energy is needed to raise the temperature of a substance per unit mass by one degree. This is captured by q = m c ΔT, where q is the energy added, m is the mass, c is the specific heat capacity, and ΔT is the temperature change. Because c is defined per kilogram, heating 1 kg by 1°C requires q = c joules. For example, water needs about 4184 J to raise 1 kg by 1°C, which shows why some substances resist temperature changes more than others. This measure is different from the energy change during freezing (latent heat of fusion) and from energy per mole (molar heat capacity), which would describe energy per mole rather than per kilogram.