Question

A sample of an aluminum has a mass of $54$ g. What is the mass of the same number of magnesium atoms ?

• A. $12$ g
• B. $24$ g
• C. $48$ g
• D. $96$ g

Answer 1

Answer: (C)

$48$ g

Molar mass $Al$ = $27$ g/mole.
$54.0$ g $Al$ $=\frac{54}{27}$ = $2$ moles of $Al$.
$2$ mole $Mg$ contains same number of atoms as $2$ moles $Al$.
Molar mass of $Mg=24$ g/mole
Mass of $2$ g $Mg=48$ g