Question

A chemist wants to make 6.0 L of a 0.340 MCaCl2 solution.

What mass of CaCl2 (in g) should the chemist use?

Answer 1

We know that Molarity , M = ( mass/ Molar mass ) x ( 1 / Volume of solution in L )

Where

M = Molarity = 0.340 M

V= Volume of solution = 6.0 L

mass of CaCl₂ = ?

Molar mass of CaCl₂ = At.mass of Ca + ( 2xAt.mass of Cl)

                                = 40 + ( 2x35.5)

                                = 111 g/mol

Plug the values we get

M = ( mass/ Molar mass ) x ( 1 / Volume of solution in L )

0.340 = ( m / 111 ) x (1 / 6.0 )

   m = 226.4g

so the mass of CaCl₂ is 226.4 g