Enthalpy: Difference between revisions

Latest revision as of 18:50, 20 February 2015

Enthalpy ( $H$ ) ^[1]^[2] is defined as:

H:=U+pV

where $U$ is the internal energy, $p$ is the pressure, $V$ is the volume. $pV$ is a conjugate pair. The differential of this function is

\left.dH\right.=dU+pdV+Vdp

\left.dH\right.=TdS-pdV+pdV+Vdp

thus we arrive at

\left.dH\right.=TdS+Vdp

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

dH=\left({\frac {\partial H}{\partial S}}\right)_{p}dS+\left({\frac {\partial H}{\partial p}}\right)_{S}dp

@@ Line 1: / Line 1: @@
-Definition:
+'''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>H:=U+pV</math>
-''(-pV)'' is a ''conjugate pair''. The differential of this function is
+where <math>U</math>  is the [[internal energy]], <math>p</math> is the [[pressure]], <math>V</math> is the volume.
+<math>pV</math> is a ''conjugate pair''. The differential of this function is
 :<math>\left.dH\right.=dU+pdV+Vdp</math>
-but from equation \ref{secondlaw} we obtain
+From the [[Second law of thermodynamics]] one obtains
 :<math>\left.dH\right.=TdS -pdV +pdV+Vdp</math>
@@ Line 15: / Line 16: @@
 :<math>\left.dH\right.=TdS +Vdp</math>
-For ''H(S,p)'' we have the following ''total differential''
+For <math>H(S,p)</math> we have the following ''total differential''
 :<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]]