Specific heat capacity
The specific heat capacity (abbreviated s, also called specific heat) of a substance is defined as the amount of heat energy required to raise the temperature of one gram of the substance by one Kelvin (equivalently one degree Celsius). Specific heat capacity is therefore heat capacity per unit mass.
Table of contents |
2 Table of specific heat capacities 3 Related concepts 4 See also |
Approximation
Actually, this is only an approximation of heat capacity. An approximation is possible because measuring the slope (derivative) of the internal energy due to random motion of atoms in a sample as a function of temperature, normalized by dividing by the mass of the sample, is normally almost linear. The SI unit for specific heat capacity is joule per kilogram per kelvin (J·kg^{-1}·K^{-1}). 1 J·kg^{-1}·K^{-1} is identical to 1 m^{2}/(s^{2}·K), which is non-intuitive, but involves only SI base units.Factors that influence heat capacity measurements:
- The temperature of the substance. For example, measuring the heat capacity of water produces different results if you start at 20 °C or 60 °C.
- Intermolecular forces. If a fluid has stronger intermolecular forces (such as hydrogen bonding in water) then the heat capacity is likely to be higher.
Table of specific heat capacities
Substance | Phase at 101.325 kPa (=1 atm), 20°C | ca. Specific heat capacity (J×g^{-1}×°C^{-1}) |
---|---|---|
Aluminum | solid | 0.900 |
Gold | solid | 0.129 |
Graphite | solid | 0.720 |
Diamond | solid | 0.502 |
Copper | solid | 0.385 |
Iron | solid | 0.444 |
Mercury | liquid | 0.139 |
Water | liquid | 4.184 |
Ethanol | liquid | 2.46 |
Related concepts
- specific melting heat
- specific heat of vaporization
See also
- Phase (matter)
- Changes of state by heat
- Latent heat
- Heat capacity temperature
- Volumetric heat capacity