Question

If the ratio of the specific heats of steam is 1.33 and R = 8312J/k mole K find the molar heat capacities of steam at constant pressure and constant volume.

• A. $33.5kJ/kmole,25.19kJ/kgK$
• B. $25.19kJ/k,33.5kJ/kgK$
• C. $18.82kJ/k,10.82kJ/kmole$
• D. None of these

Answer 1

The correct option is B $25.19kJ/k,33.5kJ/kgK$

$\gamma =\frac{c_p}{c_v}$=1.33

R = 8.312 J/k mole K

$C_p=\frac{\gamma R}{\gamma -1}$

=$\frac{1.33\times 8.312}{1.33-1}$

=$\frac{11054.96}{0.33}$

= 33.50 kJ/k mole K

similarly

$c_v=\frac{R}{\gamma -1}$

=25.187 kJ/ k moke K