Question

A vessel contains $0.5\, m ^{3}$ of hydrogen gas at $300\, K$ and pressure $10^{5} Pa$. How much heat should be added to it to raise the temperature to $500\, K$ ? Molar specific heat of hydrogen is $5\, cal / mol\, K$ :

• A. 20 kcal
• B. 10 kcal
• C. 5 kcal
• D. 2.5 kcal

Answer 1

Answer: (A)

$\Delta Q =n C \Delta T$
$\Delta Q =\frac{p V}{R T} \times C \times \Delta T$
$=\frac{10^{5} \times 0.5}{8.3 \times 300} \times 5 \times(500-300)$
$=20080\, cal \approx 20\, kcal$