## anonymous one year ago 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?

1. Rushwr

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

2. Rushwr

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

3. anonymous

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 =????

4. anonymous

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!