Question

what is the molarity of solution which contain 3.85 gram of CaCl2 dissolve in water to make 7.34cm3 of solution?​

Answer 1

The volume of solution = 7.34 cm3 => 0.00734 liters.

Mass of CaCl2 present = 3.85 grams

(Ca = 40, Cl = 35.5)

molar mass of CaCl2 = 40 + 2 x 35.5 =>40 + 71 =>111 grams per mole.

So, 3.85 grams of CaCl2 will contain 3.85/111 => 0.0346 moles (approx.)

Hence, 0.0346 moles of CaCl2 is present in 0.00734 liters of solution.

Molarity = (moles of solute )/ (liters of solution)

=> 0.0346/0.00734

=> 4.714 M (approx.)

So, the molarity of the solution is 4.714 M (molar) .