Define specific heat capacity and give its units.

Define specific heat capacity and give its units.

• A. The mass-specific energy stored.
• B. The amount of heat required to raise the temperature of 1 kg of a substance by 1 K; units J/(kg·K).
• C. Energy required to raise temperature by 10 K.
• D. The rate at which a substance conducts heat.

Answer: (B)

The main idea being tested is how much energy is needed to raise the temperature per unit mass and per degree of temperature. Specific heat capacity is defined as the amount of heat required to raise the temperature of 1 kilogram of a substance by 1 kelvin; its units are joules per kilogram per kelvin (J/(kg·K)). This follows from the equation Q = m c ΔT, where Q is heat, m is mass, c is the specific heat capacity, and ΔT is the temperature change. The units reflect energy per mass per temperature change. For example, water has a high c ≈ 4184 J/(kg·K), so heating 1 kg of water by 1 K consumes about 4184 J. The other statements don’t capture this definition: one speaks vaguely about energy per mass without tying it to a per-degree basis, another refers to a 10 K rise without normalization by mass, and the last describes conduction, not heat capacity.

The main idea being tested is how much energy is needed to raise the temperature per unit mass and per degree of temperature. Specific heat capacity is defined as the amount of heat required to raise the temperature of 1 kilogram of a substance by 1 kelvin; its units are joules per kilogram per kelvin (J/(kg·K)). This follows from the equation Q = m c ΔT, where Q is heat, m is mass, c is the specific heat capacity, and ΔT is the temperature change. The units reflect energy per mass per temperature change. For example, water has a high c ≈ 4184 J/(kg·K), so heating 1 kg of water by 1 K consumes about 4184 J. The other statements don’t capture this definition: one speaks vaguely about energy per mass without tying it to a per-degree basis, another refers to a 10 K rise without normalization by mass, and the last describes conduction, not heat capacity.