Enthalpy

Definition:

$\left.H\right.=U+pV$

(-pV) is a conjugate pair. The differential of this function is

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

From the Second law of thermodynamics one obtains

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

thus we arrive at

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 \left.dH\right.=TdS +Vdp}

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}