Question

53.6g of calcium chloride is dissolved in enough water to give 400ml of solution. what is the molarity of the solution?

What is the concentration of each ion?

How many moles of calcium chloride in 850ml of 1.27M calcium chloride?

What volume of 1.27M calcium chloride is needed if we require 4.30 moles of chloride ion?

Answer 1

a) molarity =moles of solute /volume of solution

            moles = grams/molar mass

molar mass of calcium chloride = CaCl2 = 110.98g/mol

molarity = (53.6/110.98)/0.400   =1.207 M

b) CaCl2 -> Ca2+ + 2Cl-

so, concentration of Ca2+ = concentration of CaCl2 = 1/2 concentration of Cl-

concentration of Ca2+ =1.207M

concentration of Cl- = 2.414M

c) using formula given in step a

moles = 1.27*0.850 = 1.0795

d) using formula given in step a

volume = moles/ molarity = 4.30/1.27 =3.386 litres =3386 ml