Question

How many moles of magnesium phosphate $M{g}_3(P{O}_4{)}_2$ will contain 0.25 mole of oxygen atoms?

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

Answer 1

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

In one molecule of magnesium phosphate, 8 oxygen atoms are present.
Thus, 1 mole of magnesium phosphate will contain 8 moles of oxygen.
Hence, 0.25 moles of oxygen atoms are present in $\frac{1}{8}\times 0.25=3.125\times {10}^{-2}$ moles of magnesium phosphate.