Question

A cylinder of fixed capacity $44.8$ litres contains 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 ${15}^o$C? $(R=8.31Jmo{l}^{-1}{K}^{-1}$)

• A. $265$J
• B. $310.10$J
• C. $373.95$J
• D. $387.97$J

Answer 1

The correct option is C $373.95$J

Since one mole of any ideal gas at STP occupies a volume of $22.4$here
Therefore, cylinder of fixed capacity $44.8$ litre must contain $2$ moles of helium at STP.
For helium, $C_V=\frac{3}{2}R$(monatomic)
$\therefore$ Heat needed to raise the temperature, Q$=$ number of moles $\times$ molar specific heat $\times$ raise in temperature.
$=2\times \frac{3}{2}R\times 15=45R=45\times 8.31J=373.95$J