Question

$11g$ of carbondioxide is heated at constant pressure from ${27}^{o}C$ to ${227}^{o}C$. The amount of heat transferred to carbondioxide will be

• A. $2200cal$
• B. $447cal$
• C. $220cal$
• D. $110cal$

Answer 1

The correct option is B $447cal$

Mass of the gas is given as $m=11g$ and we know that the molecular weight $M$ of $C{O}_2$ is $44$. The heat transferred is given as $Q=n{C}_p\Delta T=\frac{m}{M}{C}_p\left(200\right)$ ($n$ is the number of moles of the gas).
$C{O}_2$ is a triatomic molecule, thus its degree of freedom is 7, and we get $C_p$ as $(1+\frac{f}{2})R=(1+\frac{7}{2})R=\frac{9}{2}R$
Thus we get $Q=\frac{11}{44}\times \frac{9}{2}R\times 200=447cal$ $(R=1.987cal{K}^{-1}mo{l}^{-1})$