Question

$y\times {10}^{22}$ atoms are present in $1$ mL of Mg. What is the value of $y$?
(The density of ${}_{12}{\text{Mg}}^{24}$ is $1.74g$ $m{L}^{-1}$)

(Solve the answer upto two decimal places. Multiply the answer by 100.)

Answer 1

$y\times {10}^{22}$ atoms are present in $1$ mL of Mg.
The density of ${}_{12}{\text{Mg}}^{24}$ is $1.74g$ $m{L}^{-1}$
Since, $24g$ $Mg$ has $N$ atoms
$\therefore 1.74g$ $Mg$ or $1mL$ $Mg$ has $\frac{N\times 1.74}{24}$$=6.023\times {10}^{23}\times \frac{1.74}{24}$ $=4.37\times {10}^{22}$ atoms.
The value of $y$ is $4.37$