Given a 1.50 liters of solution that contains 62.5 grams of magnesium oxide. what is the molarity of that solution

Molarity (M) is moles over liters (moles/liters), so convert grams to moles using the molar mass of MgO and then divide the moles of MgO over the liters given.

So it would look like this:

Step 1: 62.5 g MgO x (1 mole MgO/40.31 g MgO) = 1.55 mol MgO

Step 2: 1.55 mol MgO/1.5 L = 1.03 M MgO