Question

A vessel of volume $0.2m^3$ contains hydrogen gas at temperature $300K$ and pressure $1bar$. Find the heat (in $kcal$) required to raise the temperature to $400K$. The molar heat capacity of hydrogen at constant volume is ($5cal/molK$)

• A. $4$
• B. $2$
• C. $1$
• D. $8$

Answer 1

The correct option is A $4$

Volume of hydrogen: $V=0.2m^3=0.2\times {10}^{6}c{m}^3$
No of moles of hydrogen: $n=0.987\times \frac{0.2\times {10}^6}{22.4\times {10}^3}$ since $1m^3={10}^{6}c{m}^3$

Heat required to raise the temp of hydrogen from $300K$ to $400K$: $Q=nC\Delta T=0.987\times \frac{0.2\times {10}^6}{22.4\times {10}^3}\times 5\times (400-300)=4.01kcal$