Question

A diatomic ideal gas initially at 272 K is given 100 cal heat due to which system did 209 J work. Molar heat capacity ($C_m$) of gas for the process is

• A. 3/2 R
• B. 5/2 R
• C. 5/4 R
• D. 5R

Answer 1

The correct option is D

5R

$\Delta E=q+w$

= $100-\frac{209}{4.18}=100-50=50cal$

$\Delta E=n{C}_{v,m}\Delta T$

$q=n{C}_m\Delta T$

$\frac{q}{\Delta E}=\frac{C_m}{C_{v,m}}$

$C_m=2C_{v,m}$ For diatomic gas molar heat capscity is= 5/2R

$\Rightarrow 5R$