Question

Calculate the mass of $2\times {10}^{23}$ molecules of ${NH}_3$.

Answer 1

$1$ $mole$ of Ammonia weighs $(14+3)=17$ $grams$

$1$ $mole$ of ammonia contains $6\times {10}^{23}$ molecules

$6\times {10}^{23}$ molecules $-17$ $g$

$2\times {10}^{23}$ molecules $-\left(x\right)$

$⟹x=\frac{17}{3}$

$⟹x=5.66$ $g$