Answer:
There are 0.0267 moles of oxygen in 0.658 grams of magnesium nitrate.
Explanation:
Mass of magnesium nitrate = m = 0.658 g
Molar mass of magnesium nitrate = M = 148 g/mol
Moles of magnesium nitrate = n
[tex]n=\frac{m}{M}=\frac{0.658 g}{148 g/mol}=0.004446 mol[/tex]
1 mole of magnesium nitrate has 6 moles of oxygen atoms. Then 0.004446 moles magnesium nitrate will have :
[tex]6\times 0.004446 mol=0.026676 mol\approx 0.0267[/tex]
There are 0.0267 moles of oxygen in 0.658 grams of magnesium nitrate.