Question

challenge!!!!!!!! solve this problem

Answer 1

Not much of a challenge, really.
No. of atoms of oxygen in magnesium phosphate is 8.
8 moles of oxygen atoms are contained by 1 mole of magnesium phosphate.
0.25 moles of oxygen atoms are contained by 0.25*1/8 moles of magnesium phosphate
= 31.25/1000 moles
=0.3125 moles
=3.125*10^-2 moles