Specific heat capacity

In thermodynamics, the specific heat capacity (c_p) of a substance is the heat capacity of a sample of the substance divided by the mass of the sample, also sometimes referred to as massic heat capacity. Informally, it is the amount of heat that must be added to one unit of mass of the substance in order to cause an increase of one unit in temperature. The SI unit of specific heat capacity is Joule per Kelvin per kilogram, J⋅kg⁻¹⋅K⁻¹.

For example, the heat required to raise the temperature of 1 kg of water by 1 K is 4184 Joules, so the specific heat capacity of water is ​4184 J⋅kg⁻¹⋅K⁻¹.

General

Specific heat capacity often varies with temperature, and is different for each state of matter. Liquid water has one of the highest specific heat capacities among common substances, about 4184 J⋅kg⁻¹⋅K⁻¹ at 20 °C; however, the heat capacity of ice, just below 0 °C, is only 2093 J⋅kg⁻¹⋅K⁻¹. The specific heat capacities of iron, granite, and hydrogen gas are about 449 J⋅kg⁻¹⋅K⁻¹, 790 J⋅kg⁻¹⋅K⁻¹, and 14300 J⋅kg⁻¹⋅K⁻¹, respectively.

While the substance is undergoing a phase transition, such as melting or boiling, its specific heat capacity is technically infinite, because the heat goes into changing its state rather than raising its temperature.

Specific heat capacity is an intensive property of a substance, an intrinsic characteristic that does not depend on the size or shape of the amount in consideration.

References

Relevant Sciencemadness threads

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