Question

A sample of ${\text{CO}}_{\text{2}}$ contains ${\text{2N}}_{\text{A}}$ atoms of C. From this $\frac{1}{\text{10}}$ moles of ${\text{CO}}_{\text{2}}$ are removed what will will be remaining mass of carbon dioxide in the sample?

Answer 1

Given that

No. of $C$ atoms in $C{O}_2=2N_A$

Since, each $C{O}_2$ contain $1C$ atom.

$\therefore$ No. of $C{O}_2$ molecules, $N_t=2N_A$

No. of $C{O}_2$ molecules, removed, $N_2=\frac{N_A}{10}$.

$\therefore$ No. of $C{O}_2$ molecules left, $N=N_3-N_2$

$=2N_A-\frac{N_A}{10}=(2-\frac{1}{10})N_A$

$\therefore$ No. of moles of $C{O}_2$ left, $n=\frac{N}{N_A}=\frac{1.9N_A}{N_A}$

$=1.9$ moles

$\therefore$ Mass of $C{O}_2$ left, $w=n\times M_{C{O}_2}$

$=1.9\times 44g$

$=83.6g$