Specific Heat Capacity

Specific heat capacity measures how much heat a unit mass of a substance must absorb to raise its temperature by one unit. More precisely, it is the heat required to raise the temperature of one kilogram of the substance by one kelvin, under specified conditions and without a phase change.

Measurement and relation

When specific heat capacity is approximately constant, heat transfer is expressed as Q = mcΔT, where Q is heat supplied, m is mass, c is specific heat capacity and ΔT is the temperature change. Its SI unit is J kg⁻¹ K⁻¹.

Physical significance

Specific heat capacity indicates a substance's mass-specific thermal inertia. A substance with a higher value requires more heat for the same mass and temperature rise, so it generally warms and cools more slowly under comparable heat transfer conditions.

• Specific heat capacity is an intensive property, because its value does not depend on the amount of substance.
• Its value can vary with temperature, physical state and, particularly for gases, the thermodynamic conditions.

Distinction from related properties

• Heat capacity is the heat needed to raise the temperature of an entire body by one kelvin, and equals mass multiplied by specific heat capacity.
• Latent heat concerns energy absorbed or released during a phase change without a temperature change.
• Thermal conductivity measures how readily heat flows through a material, not how much heat is required to change its temperature.