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Many thermodynamic equations are expressed in terms of partial derivatives. For example, the expression for the heat capacity at constant pressure is: = which is the partial derivative of the enthalpy with respect to temperature while holding pressure constant.
An equivalent statement of the Dulong–Petit law in modern terms is that, regardless of the nature of the substance, the specific heat capacity c of a solid element (measured in joule per kelvin per kilogram) is equal to 3R/M, where R is the gas constant (measured in joule per kelvin per mole) and M is the molar mass (measured in kilogram per mole).
Its published results did much to bring about general acceptance of Joule's work and the kinetic theory. However, in 1848, von Mayer had first had sight of Joule's papers and wrote to the French Académie des Sciences to assert priority. His letter was published in the Comptes Rendus and Joule was quick to react. Thomson's close relationship ...
In other words, that theory predicts that the molar heat capacity at constant volume c V,m of all monatomic gases will be the same; specifically, c V ,m = 3 / 2 R where R is the ideal gas constant , about 8.31446 J⋅K −1 ⋅mol −1 (which is the product of the Boltzmann constant k B and the Avogadro constant ).
Instead, the common practice is to measure the specific heat capacity at constant pressure (allowing the material to expand or contract as it wishes), determine separately the coefficient of thermal expansion and the compressibility of the material, and compute the specific heat capacity at constant volume from these data according to the laws ...
James Joule was born in 1818, the son of Benjamin Joule (1784–1858), a wealthy brewer, and his wife, Alice Prescott, on New Bailey Street in Salford. [3] Joule was tutored as a young man by the famous scientist John Dalton and was strongly influenced by chemist William Henry and Manchester engineers Peter Ewart and Eaton Hodgkinson. He was ...
The joule (/ dʒ uː l / JOOL, or / dʒ aʊ l / JOWL; symbol: J) is the unit of energy in the International System of Units (SI). [1] In terms of SI base units, one joule corresponds to one kilogram-square metre per square second (1 J = 1 kg⋅m 2 ⋅s −2).
This led Joule to reject the caloric theory (at that time the dominant theory) in favor of the mechanical theory of heat (according to which heat is another form of energy). [5] Resistive heating was independently studied by Heinrich Lenz in 1842. [1] The SI unit of energy was subsequently named the joule and given the symbol J.