Question

$2$ $\text{moles}$ of an ideal diatomic gas is initially at $300\text{K}$. If heat of $300\text{J}$ is added to it at constant pressure, then the final temperature of the gas is

• A. $30.5\text{K}$
• B. ${305.15}^{\circ }\text{C}$
• C. $305.15\text{K}$
• D. ${30.5}^{\circ }\text{C}$

Answer 1

The correct option is C $305.15\text{K}$

Given, that the gas is diatomic
$\therefore C_V=\frac{5R}{2}\Rightarrow C_P=\frac{7R}{2}$
Heat supplied $\left(Q\right)=300\text{J}$
From, $Q=n{C}_P\Delta T$
$Q=n\frac{7R}{2}\times (T_f-T_i)$
$300=\frac{2\times 7\times 8.314\times (T_f-300)}{2}$
$\Rightarrow T_f=305.15\text{K}$