$2.8\times {{10}^{{-3}}}~\text{mol}$ of $\text{C}{{\text{O}}_{2}}$ is left after removing ${{10}^{{21}}}$ molecules from its 'X' mg sample. The mass of $\text{C}{{\text{O}}_{2}}$ taken initially is
Given: ${{\text{N}}_{\text{A}}}=6.02\times {{10}^{{23}}}~\text{mo}{{\text{l}}^{{-1}}}$
