Question

How many moles of Magnesium Phosphate $\left(M{g}_3\right(P{O}_4{)}_2)$ will contain $0.25$ mole of oxygen atoms?

• A. $2.5\times {10}^{-2}$
• B. $2\times {10}^{-2}$
• C. $1.25\times {10}^{-2}$
• D. $3.125\times {10}^{-2}$

Answer 1

The correct option is D $3.125\times {10}^{-2}$

Explanation:
In one molecule of $M{g}_3(P{O}_4{)}_2$ there are $8$ Oxygen atoms
So in $1$ mole of $M{g}_3(P{O}_4{)}_2$ molecules, there will be $8$ moles of Oxygen atoms.
$1$ mole of $M{g}_3(P{O}_4{)}_2\to 8$ moles of $O$ atoms
$X\to 0.25$ moles of $O$ atoms
Cross multiplying,
$0.25\times 1=8X$
$X=0.25/8$
$X=3.125\times {10}^{-2}$
$3.125\times {10}^{-2}$ moles of Magnesium Phosphate will contain $0.25$ mole of oxygen atoms.