Question

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

• A. $0.02$
• B. $3.125\times 10^{-2}$
• C. $1.25\times 10^{-2}$
• D. $2.5\times 10^{-2}$

Answer 1

Answer: (B)

$M{g}_3(P{O}_4{)}_2$; mole
8 moles of O-atom are contained by 1 mole $M{g}_3(P{O}_4{)}_2$.
Hence, 0.25 moles of O-atom $=\frac{1}{8}\times 0.25$
$=3.125\times 10^{-2}$