A 2.00 M solution of calcium choloride in water has a density of 1.17g/mL. What is the mole fraction of calcium chloride?

How do I solve this? I know that density=mass/volume. The mm of calcium chloride is 111g/mol. I don't know how to connect this information.

1 answer

2.00 M = 2.00 mols/Liter of solution.
Convert 2.00 M to grams CaCl2 in the solution.
1 L of the solution has a mass of 1.17 x 1000. That is the mass of the water + the mass of the CaCl2.
Subtract mass CaCl2 to obtain mass H2O.

Now you have the mass and # mols CaCl2 and the mass of H2O.
Can you go from here?
mol fraction X = molsX/(mols x + mols y)