How many moles of magnesium phosphate, Mg_(3)(PO_(4))_(2) will contain 0.25 mole of oxygen atoms ?

How many moles of magnesium phosphate, Mg_(3)(PO_(4))_(2) will contain

1.	How many moles of magnesium phosphate, Mg_(3)(PO_(4))_(2) will contain 0.25 mole of oxygen atoms ?
Answer» 0.02 `3.125 xx 10^(-2)` `1.25 xx 10^(-2)` `2.5 xx 10^(-2)` Solution :`UNDERSET("1 MOLE")(Mg_(3)(PO_(4))_(2))-=underset("8 mole")(8(O))` 8 mole of oxygen ATOMS are present in `Mg_(3)(PO_(4))_(2)=1` mole 0.25 mole of oxygen atoms are present in `Mg_(3)(PO_(4))_(2)` `=(1xx0.25)/(8)=3.125xx10^(-2)` mole.