Chemistry 2 chapter 13 or 14 question

Question

A 4.17 ppm solution of BaCl2 in water has a density of 1.24 g/mL. What is the molarity?

Answer 1

Molarity = moles of solute / Liter of solution.

4.17 ppm BaCl₂ = 4.17 mg BaCl2 / L solution

molar mass BaCl₂ = 208.2 g / mol

4.17 mg / L x 1 g / 1000 mg x 1 mol / 208.2 g = 2.00x10^-5 mols BaCl₂ / Liter = 2.00x10^-5 M BaCl₂

The density does not play a role in the calculation of molarity. I would play a role in the calculation of molality.