The table of specific heat capacities gives the
volumetric heat capacity as well as the
specific heat capacity
In thermodynamics, the specific heat capacity (symbol ) 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 t ...
of some substances and engineering materials, and (when applicable) the
molar heat capacity.
Generally, the most notable constant parameter is the volumetric heat capacity (at least for solids) which is around the value of 3
megajoule per
cubic meter per
kelvin
The kelvin, symbol K, is the primary unit of temperature in the International System of Units (SI), used alongside its prefixed forms and the degree Celsius. It is named after the Belfast-born and University of Glasgow-based engineer and ph ...
:
Note that the especially high ''molar'' values, as for paraffin, gasoline, water and ammonia, result from calculating specific heats in terms of moles of ''molecules''. If specific heat is expressed per mole of ''atoms'' for these substances, none of the constant-volume values exceed, to any large extent, the theoretical
Dulong–Petit limit of 25 J⋅mol
−1⋅K
−1 = 3
''R'' per mole of atoms (see the last column of this table). For example, Paraffin has very large molecules and thus a high heat capacity per mole, but as a substance it does not have remarkable heat capacity in terms of volume, mass, or atom-mol (which is just 1.41 ''R'' per mole of atoms, or less than half of most solids, in terms of heat capacity per atom). Dulong–Petit limit also explains why
dense substance which have very heavy atoms, such like lead, rank very low in mass heat capacity.
In the last column, major departures of solids at standard temperatures from the
Dulong–Petit law value of 3 ''R'', are usually due to low atomic weight plus high bond strength (as in diamond) causing some vibration modes to have too much energy to be available to store thermal energy at the measured temperature. For gases, departure from 3 ''R'' per mole of atoms is generally due to two factors: (1) failure of the higher quantum-energy-spaced vibration modes in gas molecules to be excited at room temperature, and (2) loss of potential energy degree of freedom for small gas molecules, simply because most of their atoms are not bonded maximally in space to other atoms, as happens in many solids.
A Assuming an altitude of 194 metres above mean sea level (the worldwide median altitude of human habitation), an indoor temperature of 23 °C, a dewpoint of 9 °C (40.85% relative humidity), and 760 mmHg sea level–corrected barometric pressure (molar water vapor content = 1.16%).
B Calculated values
*Derived data by calculation. This is for water-rich tissues such as brain. The whole-body average figure for mammals is approximately 2.9 J⋅cm−3⋅K−1
Mass heats capacity of building materials
(Usually of interest to builders and solar )
See also
*
List of thermal conductivities
References
{{reflist
Heat conduction