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The term specific heat may also refer to the ratio between the specific heat capacities of a substance at a given temperature and of a reference substance at a reference temperature, such as water at 15 °C; [5] much in the fashion of specific gravity. Specific heat capacity is also related to other intensive measures of heat capacity with ...
The difference relation allows one to obtain the heat capacity for solids at constant volume which is not readily measured in terms of quantities that are more easily measured. The ratio relation allows one to express the isentropic compressibility in terms of the heat capacity ratio.
The SI unit of heat capacity is joule per kelvin (J/K). Heat capacity is an extensive property. The corresponding intensive property is the specific heat capacity, found by dividing the heat capacity of an object by its mass. Dividing the heat capacity by the amount of substance in moles yields its molar heat capacity.
For example, if 250 J of heat energy is added to a copper gear with a thermal mass of 38.46 J/°C, its temperature will rise by 6.50 °C. If the body consists of a homogeneous material with sufficiently known physical properties, the thermal mass is simply the mass of material present times the specific heat capacity of that material.
Heat capacity is a measurable physical quantity equal to the ratio of the heat added to an object to the resulting temperature change. [76] The molar heat capacity is the heat capacity per unit amount (SI unit: mole) of a pure substance, and the specific heat capacity, often called simply specific heat, is the heat capacity per unit mass of a ...
Since the molar heat capacity of a substance is the specific heat c times the molar mass of the substance M/N its numerical value is generally smaller than that of the specific heat. Paraffin wax, for example, has a specific heat of about 2500 J⋅K −1 ⋅kg −1 but a molar heat capacity of about 600 J⋅K −1 ⋅mol −1.
The volumetric heat capacity can also be expressed as the specific heat capacity (heat capacity per unit of mass, in J⋅K −1 ⋅kg −1) times the density of the substance (in kg/L, or g/mL). [1] It is defined to serve as an intensive property .
See relations between specific heats for the derivation of the thermodynamic relations between the heat capacities. The above definition is the approach used to develop rigorous expressions from equations of state (such as Peng–Robinson ), which match experimental values so closely that there is little need to develop a database of ratios or ...