定圧モル比熱　

$\displaystyle \Delta U$	$\textstyle =$	$\displaystyle Q - W' = Q - p\Delta V$	(24)
$\displaystyle Q$	$\textstyle =$	$\displaystyle \Delta U + p\Delta V$	(25)
$\displaystyle \Delta U$	$\textstyle =$	$\displaystyle \frac{3}{2}nR\Delta T　p\Delta V = nR\Delta T$
$\displaystyle Q$	$\textstyle =$	$\displaystyle \frac{3}{2}nR\Delta T + nR\Delta T = \frac{5}{2}nR\Delta T$	(26)
$\displaystyle C_p$	$\textstyle =$	$\displaystyle \frac{{\frac{5}{2}nR\Delta T}}{{n\Delta T}} = \frac{5}{2}R$	(27)