# What is the molarity if 90 grams of magnesium oxide is present in 750 mL of solution?

The solution is $3$ $\text{M}$
The moles of magnesium oxide $= \frac{90}{40} = 2.25$ mols
$\text{n"="cv" rarr"c" = "n"/"v}$
$\frac{2.25}{750 \div i \mathrm{de} 1000} = 3$ $\text{mol}$ ${\text{dm}}^{3}$