Question

$175$ calorie of heat is required to raise the temperature of $5$ mole of an ideal gas at constant pressure from $30^\circ\,C$ to $35^\circ\,C$. The amount of heat required to raise temperature of same gas from $30^\circ\,C$ to $35^\circ\,C$ constant volume will be

• A. 75 cal
• B. 125 cal
• C. 150 cal
• D. 250 cal

Answer 1

Answer: (B)

125 cal

Answer 2

Here $5 \times C_p \times 5$ = 175 cal. Here $C_p$ = 7 cal mol$^{-1}$ K$^{-1}$ $C_{\nu} = C_p$ - R = 5 cal mol$^{-1}$ Hence heat required for heating the gas at constant volume = 5 $\times$ 5 $\times$ 5 = 125 cal