Enthalpy: Difference between revisions

Revision as of 15:06, 12 March 2012

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

H = U + p V

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

d H = d U + p d V + V d p

d H = T d S - p d V + p d V + V d p

thus we arrive at

d H = T d S + V d p

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

d H = {(\frac{\partial H}{\partial S})}_{p} d S + {(\frac{\partial H}{\partial p})}_{S} d p

@@ Line 3: / Line 3: @@
 :<math>\left.H\right.=U+pV</math>
-where <math>U</math>  is the [[internal energy]], <math>p</math> is the [[pressure]], <math>V</math> is the volume and ''(-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>
@@ 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>