Calculate the molarity of an aqueous solution that is 18.2% by mass calcium chloride. you might need to know that the density is 1.18 g/ml.

Explanation:

1) Data:

a) M = ?

b) % mass = 18.2%

c) Solute: CaCl₂

d) d = 1.18 g/ml

2) Formulae:

a) Molarity

M = n/V, where M is molarity, n is number of moles of solute, and V is the volumen of solution in liters.

b) Density

d = m/V, where d is the density of the solution, m is the mass in grams, V is the volume in liters.

c) Number of moles

n = mass in grams / molar mass, where n is the number of moles.

d) % mass

% = (mass of solute / mass of solution) × 100

3) Solution:

a) Start by assuming a base amount: 100 g of solution.

b) Calcualte the volume (V) of the solution:

                            V = 100 g / 1.18 g/ml = 84.75 ml

                            V = 0.08475 liter

c) Calculate the mass of solute:

        ⇒ mass of solute = % × mass of solution / 100 = 18.2 × 100 g / 100

            mass of soiute = 18.2 g

d) Calculate the number of moles of solute (n)

e) Calculate the molarity (M) of the solution

The answer is reported with 3 significant figures, since the data have 3 significant figures.