Measures of Heat
..... Click the link for more information. energy of a unit mass of a substance to the change in temperature temperature, measure of the relative warmth or coolness of an object. Temperature is measured by means of a thermometer or other instrument having a scale calibrated in units called degrees. The size of a degree depends on the particular temperature scale being used.
..... Click the link for more information. of the substance; like its melting point or boiling point, the heat capacity is a characteristic of a substance. The measurement of heat and heat capacity is called calorimetry calorimetry (kăl'ərĭm`ətrē), measurement of heat and the determination of heat capacity .
..... Click the link for more information. . In the metric system, heat capacity is often expressed in units of calories calorie, abbr. cal, unit of heat energy in the metric system. The measurement of heat is called calorimetry . The calorie, or gram calorie, is the quantity of heat required to raise the temperature of 1 gram of pure water 1°C;.
..... Click the link for more information. per gram per degree Celsius (cal/g-°C;); in the English system, British thermal units British thermal unit, abbr. Btu, unit for measuring heat quantity in the customary system of English units of measurement , equal to the amount of heat required to raise the temperature of one pound of water at its maximum density [which occurs at a temperature of 39.
..... Click the link for more information. per pound per degree Fahrenheit (Btu/lb-°F;) are often used. Because of the definitions of the calorie and Btu, these two heat capacity units are equivalent; the heat capacity of pure water is 1 cal/g-°C; and 1 Btu/lb-°F;. Other units are used also; for example, the heat capacity of pure water is 4.184 joules/g-°C; and 1.16x10−6 kilowatt-hours/g-°C;. The heat capacity of a system such as a calorimeter refers to the ratio of the change in heat energy of the system as a whole to the change in its temperature and is expressed in such units as calories per degree Celsius. See also specific heat specific heat, ratio of the heat capacity of a substance to the heat capacity of a reference substance, usually water. Heat capacity is the amount of heat needed to change the temperature of a unit mass 1°.
..... Click the link for more information. .
heat capacity
Ratio of heat absorbed by a material to the change in temperature. It is usually expressed as calories per degree in terms of the amount of the material being considered. Heat capacity and its temperature variation depend on differences in energy levels for atoms. Heat capacities are measured with a calorimeter and are important as a means of determining the entropies of materials. See also specific heat.
Heat capacity
The quantity of heat required to raise a unit mass of homogeneous material one unit in temperature along a specified path, provided that during the process no phase or chemical changes occur, is known as the heat capacity of the material in question. Moreover, the path is so restricted that the only work effects are those necessarily done on the surroundings to cause the change to conform to the specified path. The path is usually at either constant pressure or constant volume.
In accordance with the first law of thermodynamics, heat capacity at constant pressure Cp is equal to the rate of change of enthalpy with temperature at constant pressure ∂H/∂T)p. Heat capacity at constant volume Cv is the rate of change of internal energy with temperature at constant volume (∂U/∂T)v. Moreover, for any material, the first law yields the relation 
See Enthalpy, Internal energy, Thermodynamic principles
Heat capacity
The quantity of heat required to raise a unit mass of homogeneous material one unit in temperature along a specified path, provided that during the process no phase or chemical changes occur, is known as the heat capacity of the material in question. Moreover, the path is so restricted that the only work effects are those necessarily done on the surroundings to cause the change to conform to the specified path. The path is usually at either constant pressure or constant volume.
In accordance with the first law of thermodynamics, heat capacity at constant pressure Cp is equal to the rate of change of enthalpy with temperature at constant pressure. Heat capacity at constant volume Cv is the rate of change of internal energy with temperature at constant volume. Moreover, for any material, the first law yields the relation
See Enthalpy, I<SCP>nternal energy</SCP>, T<SCP>hermodynamic principles</SCP>.
How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content.
| ?Page tools | ||
|---|---|---|
|