A cylinder with fixed capacity of 67.2 lit contains helium gas at STP. The amount of heat needed to raise the temperature of the gas by 20°C is: [Given that R = 8.31 J mol-1 K-1]

Question

A cylinder with fixed capacity of 67.2 lit contains helium gas at STP. The amount of heat needed to raise the temperature of the gas by 20°C is: [Given that R = 8.31 J mol-1 K-1] (A) 748 J (B) 374 J (C) 350 J (D) 700 J

Tardigrade Admin · Accepted Answer

Δ Q = nCV Δ T = n (3/2) RΔ T = ((67.2/22.4))((3/2) ×8.31)(20) ≈748 J

Q. A cylinder with fixed capacity of $67.2$ lit contains helium gas at STP. The amount of heat needed to raise the temperature of the gas by $2 0^{\circ} C$ is : [Given that $R = 8.31 J m o l^{- 1} K^{- 1}$ ]

748 J

374 J

350 J

700 J

$Δ Q = n C_{V} Δ T = n \frac{3}{2} R Δ T$
$= (\frac{67.2}{22.4}) (\frac{3}{2} \times 8.31) (20)$
$\approx 748 J$

Q. A cylinder with fixed capacity of 67.2 lit contains helium gas at STP. The amount of heat needed to raise the temperature of the gas by 20∘C is : [Given that R=8.31Jmol−1K−1]