A cylinder of fixed capacity 44.8 litres constains helium gas at standard temperature and pressure. What is the amount of heat needed to raise the temperature of the gas in the cylinder by 15^(@)C ? Given R=8.31 j mol e^(-1) K^(-1) . (For monoatomic gas, C_(v)=3 R//2)

A cylinder of fixed capacity 44.8 litres constains helium gas at stand

1.	A cylinder of fixed capacity 44.8 litres constains helium gas at standard temperature and pressure. What is the amount of heat needed to raise the temperature of the gas in the cylinder by 15^(@)C ? Given R=8.31 j mol e^(-1) K^(-1) . (For monoatomic gas, C_(v)=3 R//2)
Answer» 265 J `310.10 J` `373.95 J` `387.97 J` Solution :Since ONE mole of any ideal gas at STP OCCUPIES a volume of 22.4 litre. Therefore, cylinder of fixed CAPACITY 44.8 litre must contain 2 moles of helium at STP. For helium, `C_(V)=3/2R` (monatomic) `therefore` Heat needed to raise the temperature, Q= NUMBER of moles `xx` molar specific heat `xx` raise in temperature `=2xx3/2Rxx15=45R=45xx8.31J=373.95J`