A 0.820 𝑚 aqueous solution of KBr has a total mass of 70.0 g. What masses of solute and solvent are present?

Answer 1

Molar mass KBr = 119 g / mol

0.820 m means 0.820 moles KBr per kg of water

0.820 mol KBr x 119 g / mol = 97.58 g KBr / 1000 g H₂O

Total mass of solution would be 97.58 g + 1000 g = 1098 g

70.0 g / 1098 g = 0.06375

Mass KBr = 0.06375 x 97.58 = 6.22 g KBr

Mass H₂O = 0.06375 x 1000 = 63.75 g H₂O