Question

A sample of aluminium has a mass of $54.0\text{g}$. What is the mass of the same number of magnesium atoms?
(Atomic weight of $Al=27\text{u},Mg=24\text{u}$)

• A. $12\text{g}$
• B. $24\text{g}$
• C. $48\text{g}$
• D. $96\text{g}$

Answer 1

The correct option is C $48\text{g}$

Given, mass of $Al=54\text{g}$
Moles of $Al=\frac{54}{27}=2\text{mol}$
So number of $Mg$ atoms = $2\text{mol}$
$\therefore$ Mass of $Mg=2\times 24=48\text{g}$