A cylinder of fixed capacity of 44.8 litres contains helium gas at standard temperature and pressure. The amount of heat needed to raise the temperature of gas in the cylinder by 20.0° C will be: (Given gas constant R =8.3 JK -1- moI -1 )

Question

A cylinder of fixed capacity of 44.8 litres contains helium gas at standard temperature and pressure. The amount of heat needed to raise the temperature of gas in the cylinder by 20.0° C will be: (Given gas constant R =8.3 JK -1- moI -1 ) (A) 249 J (B) 415 J (C) 498 J (D) 830 J

Tardigrade Admin · Accepted Answer

No of moles =(44.8/22.4)=2 Gas is mono atomic so C v =(3/2) R Δ Q = nC v Δ T =2 × (3/2) R (20) =60 R =60 × 8.3 =498 J

Q. A cylinder of fixed capacity of $44.8$ litres contains helium gas at standard temperature and pressure. The amount of heat needed to raise the temperature of gas in the cylinder by $20. 0^{\circ} C$ will be : (Given gas constant $R = 8.3 J K^{- 1} - m o I^{- 1}$ )

249 J

415 J

498 J

830 J

No of moles $= \frac{44.8}{22.4} = 2$
Gas is mono atomic so $C_{v} = \frac{3}{2} R$
$Δ Q = n C_{v} Δ T$
$= 2 \times \frac{3}{2} R (20)$
$= 60 R$
$= 60 \times 8.3$
$= 498 J$

Q. A cylinder of fixed capacity of 44.8 litres contains helium gas at standard temperature and pressure. The amount of heat needed to raise the temperature of gas in the cylinder by 20.0∘C will be : (Given gas constant R=8.3JK−1−moI−1 )