Question

What is the molarity of barium chloride, BaCl2, in the final solution prepared by dissolving 2.50 g of barium chloride dihydrate, BaCl2 • 2 H2O , in enough
water to make 400. mL of solution?

Answer 1

\[Molarity = \frac{ Moles of BaCl2 }{ Volume of the solution }\]

Answer 2

First find the no. of moles of BaCl2
Use n= mass / molar mass

Answer 3

1) calculate the molecular mass of the BaCl2 • 2 H2O, look for the atomic mass of the elements in the periodic table and and include the H2O too

2) calculate the number of moles in 2.50g of BaCl2 • 2 H2O

2.50 g BaCl2 • 2 H2O x 1 mol BaCl2 • 2 H2O/ molecular mass BaCl2 • 2 H2O = ???

3) calculate the molarity
M= moles of solute /L solution

moles of BaCl2 • 2 H2O / 0.400L =????

Answer 4

Oh okay. I didn't think that you would need to add the molar mass of the dihydrate so I just used the molar mass of BaCl2. Thanks!