In the laboratory you dissolve 24.9 g of aluminum sulfate in a volumetric flask and add water to a total volume of 125 . mL.

Question

In the laboratory you dissolve 24.9 g of aluminum sulfate in a volumetric flask and add water to a total volume of 125 . mL.

Answer 1

Assuming you are trying to find the molarity of the aluminum sulfate solution, you might proceed as follows:

molar mass aluminum sulfate, Al₂(SO₄)₃ = 342 g / mol

molarity (M) is defined as moles of solute / liter of solution

moles solute = 24.9 g Al₂(SO₄)₃ x 1 mol Al₂(SO₄)₃ / 342 g = 0.0728 moles Al₂(SO₄)₃

liters of solution = 125. ml x 1 L / 1000 ml = 0.125 L

molarity of solution = 0.0728 moles / 0.125 L = 0.582 M