Question

The density of a 0.448-m aqueous solution of K2CrO4 is 1.063 g/mL. What is the molarity (M) of this solution? The molar mass if K2CrO4 is 194.2 g/mol. 0

Answer 1

Answer:

[K₂CrO₄] = 0.44 M

Explanation:

Solute → K₂CrO₄

Solvent → Water

0.448 m means molality. These are the moles in 1kg of solvent so we can determine the mass like this:

Mass of solute → moles of salt . molar mass = 0.448 mol . 194.2 g/mol = 87 g

Mass of solvent → 1000 g

Mass of solution → Mass of solute + Mass of solvent → 1087 g

Let's determine the volume of solution by density:

Solution density = Solution mass . Solution volume

Solution volume = Solution mass / Solution density → 1087 g / 1.063 g/mL = 1022.5 mL

Let's convert the volume to L in order to determine M

1022.5 mL . 1L/ 1000 mL = 1.02L

M → mol/L → 0.448 mol / 1.02L = 0.44 M