Question

The change in internal energy of two moles of a monoatomic gas, when the temperature increases by ${50}^{\circ }\text{C}$ is
[Take $R=2{\text{cal mol}}^{-1}{}^{\circ }{\text{C}}^{-1}$]

• A. $300\text{J}$
• B. $1251\text{J}$
• C. $300\text{cal}$
• D. $1251\text{cal}$

Answer 1

The correct option is C $300\text{cal}$

Given, that the gas is monoatomic
No. of moles of monoatomic gas given is, $n=2$
Therefore,
$\Delta U=\frac{3}{2}nR\Delta T$
$\Rightarrow \Delta U=\frac{3}{2}\times 2\times 2\times 50=300\text{cal}$