Question

A diatomic gas with rigid molecules does $10J$ of work when expanded at constant pressure. What would be the heat energy absorbed by the gas, in this process?

• A. $40J$
  
• B. $30J$
  
• C. $35J$
  
• D. $25J$

Answer 1

The correct option is C $35J$


Given, work done by the gas, $W=10J$
For a diatomic gas, $C_P=\frac{7}{2}R$
Since gas undergoes isobaric process
$\Rightarrow \Delta Q=n{C}_P\Delta T$
$\therefore \Delta Q=n\frac{7}{2}R\Delta T=\frac{7}{2}\left(nR\Delta T\right)$

Also, $W=nR\Delta T=10J$

$\Rightarrow \Delta Q=35J$

Final answer: (𝑎)