Question

A 3.17 m solution of cacl2 in water has a density of 1.24 g/ml. what is the molarity?

Answer 1

Given the molality of CaCl2 solution = 3.17 m

That means 3.17 mol
`CaCl_(2)` are present per 1 kg water.

Mass of
`CaCl_(2)` =
`3.17 mol CaCl_(2) * (110.98 g)/(1 mol)  =351.8 g CaCl_(2)`

Mass of solution = Mass of solvent + Mass of Solute = 1000 g + 351.8 g = 1351.8 g solution.

Density of solution = 1.24 g/mL

Volume of the solution =
`1351.8 g * (1mL)/(1.24 g) = 1090 mL`

Molarity is the moles of solute per L of the solution

Calculating molarity of the solution:

`(3.17 mol)/(1090mL*(1L)/(1000mL) ) =2.908 M`