Question

The number of atoms in $5.3$ gm of $N{a}_{2}C{O}_3$ is $x\times {10}^{22}$.What is the value of $x$?

[Round off to nearest integer]

Answer 1

$(2\times 23+12+48)gm?\to Na$ molecules

$N{a}_2{10}_3$

$\Rightarrow 5.3gm$ of $N{a}_2{10}_3\to \frac{5.3}{(46+12+48)}$ Na molecules of $N{a}_{2}C{O}_3$

$\Rightarrow 0.301Na$ molecules of $N{a}_{2}C{O}_3$

$\Rightarrow 1$ molecules $N{a}_{2}C{O}_3\to 6$ atoms

$0.3Na$ molecules of $N{a}_{2}C{O}_3\to 1.8Na$ atoms

$\to 18\times {10}^{22}$ atoms