Question

A sample of ${Na}_2{CO}_3$ contains $6.02\times {10}^{23}{Na}^{+}ions$. The mass of the sample is: $(at.massofNa=23,C=12,O=16)$

Answer 1

$1$ mole of sample $\left(N{a}_{2}C{O}_3\right)$ contains $2$ moles of $N{a}^{+}$ ions.

Moles of $N{a}^{+}$ ions= $\frac{No.ofionsinonemoleofN{a}^{+}ion}{Totalno.ofN{a}^{+}ions}$

=$\frac{6.022\times {10}^{23}}{6.022\times {10}^{23}}$

=$1$ mole

$\therefore$ Moles of sample=$\frac{1}{2}=0.5$ moles.

$\therefore$ Mass of sample= $No.ofmoles\times Molecularmass$

=$0.5\times \left[\right(23\times 2)+12+(16\times 3\left]\right]$

$\therefore$ Mass of sample= $53$ $grams$