Enthalpy: Difference between revisions

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Definition of the enthalpy, ''H''
'''Enthalpy''' (<math>H</math>) <ref>[http://www.dwc.knaw.nl/DL/publications/PU00013601.pdf J. P. Dalton "Researches on the Joule-Kelvin effect, especially at low temperatures. I. Calculations for hydrogen", KNAW Proceedings '''11''' pp.  863-873 (1909)]</ref><ref>[http://dx.doi.org/10.1021/ed079p697 Irmgard K. Howard "H Is for Enthalpy, Thanks to Heike Kamerlingh Onnes and Alfred W. Porter", Journal of Chemical Education '''79''' pp. 697-698 (2002)]</ref> is defined as:


:<math>\left.H\right.=U+pV</math>
:<math>\left.H\right.=U+pV</math>
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:<math>dH=\left(\frac{\partial H}{\partial S}\right)_p dS + \left(\frac{\partial H}{\partial p}\right)_S dp</math>
:<math>dH=\left(\frac{\partial H}{\partial S}\right)_p dS + \left(\frac{\partial H}{\partial p}\right)_S dp</math>
==References==
<references/>
[[Category: Classical thermodynamics]]
[[Category: Classical thermodynamics]]

Revision as of 15:54, 12 March 2012

Enthalpy () [1][2] is defined as:

where is the internal energy, is the pressure, is the volume and (-pV) is a conjugate pair. The differential of this function is

From the Second law of thermodynamics one obtains

thus we arrive at

For H(S,p) we have the following total differential

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle dH=\left(\frac{\partial H}{\partial S}\right)_p dS + \left(\frac{\partial H}{\partial p}\right)_S dp}

References