Question

A balloon contain $1000kg$ of air. If its temperature is changed by ${60}^{o}C$ then find change in thermal energy of air.

• A. $20\times {10}^{8}J$
• B. $56\times {10}^{2}J$
• C. $17.2\times {10}^{6}J$
• D. $34\times {10}^{5}J$

Answer 1

The correct option is C $17.2\times {10}^{6}J$

Given$-$

$W=1000kg$

$\Delta T=60°C=60K$

As standard convention, molar mass of air is taken as $0.029kg/mol.$

No of moles of air in balloon-

$n=1000/0.029$

$n=34483$

Change in thermal energy of air is calculated by-

$\Delta E=nR\Delta T$

$\Delta E=34482\times 8.314\times 60$

$\Delta E=17.2\times {10}^{6}J$

hence,

option $\left(C\right)$ is correct answer.