What number of magnesium ATOMS are contained in a 12*g mass of the metal?

Mar 16, 2017

$\text{Number of atoms......= } 3.011 \times {10}^{23}$

Explanation:

$\text{Number of atoms of Mg}$ $\equiv$ $\text{Mass of metal"/"Molar mass of metal} \times {N}_{A}$,

where ${N}_{A} \equiv \text{Avogadro's number} = 6.022 \times {10}^{23} \cdot m o {l}^{-} 1$

$\text{Number of atoms of Mg}$ $\equiv$ $\frac{12 \cdot g}{24.31 \cdot g \cdot m o {l}^{-} 1} \times {N}_{A}$,
$= \frac{1}{2} \cdot \cancel{m o l} \times 6.022 \times {10}^{23} \cdot \cancel{m o {l}^{-} 1}$
$= 3.011 \times {10}^{23}$, a $\text{noomber}$ as required.........