Chemistry - Mole Concept Question with Solution | TestHub

Moles of removed ${\mathrm{CO}}_2=\frac{10^{21}}{6.02\times 10^{23}}\mathrm{mol}$ $=1.66\times 10^{-3}\mathrm{mol}$ mole of ${\mathrm{CO}}_2$ left $=2.8\times 10^{-3}\mathrm{moles}$ total moles of ${\mathrm{CO}}_2$ taken initially $=(2.8+1.66)\times 10^{-3}\mathrm{mol}$ mass of ${\mathrm{CO}}_2$ taken initially $\begin{array}{rl}& =4.46\times 10^{-3}\times 44\\ & =196.24\times 10^{-3}\mathrm{g}\\ & =196.24\mathrm{mg}\end{array}$