Question

When 229 J of energy is supplied as heat at constant pressure to 3.0mol Ar(g) the temperature of the sample increases by 2.55K. Calculate the molar heat capacities at constant volume and constant pressure of the gas.

Answer 1

Answer:

The answer is "$\bold{21.616\ \ \frac{J}{mol K}}$".

Explanation:

when it is a constant pressure:

$Cp= \frac{\Delta q}{n\Delta T}$

$=\frac{229}{3\times 2.55}\\\\=\frac{229}{7.65}\\\\=29.93 \frac{J}{mol\ K}$

and,  

$Cp-Cv=R\ \ (Mayer's\ formula)$

then,

$Cv=Cp-R$  

    $=29.93-8.314\\\\=21.616\ \ \frac{J}{mol K}$