Here's how to calculate the percent w-w (weight-to-weight) concentration:

1. Calculate the mass of the solution:

* Density = Mass / Volume

* Mass = Density * Volume

* Mass = 1.13 g/mL * 240 mL = 271.2 g

2. Calculate the percent w-w concentration:

* Percent w-w = (Mass of solute / Mass of solution) * 100%

* Percent w-w = (1.20 g / 271.2 g) * 100%

* Percent w-w = 0.443%

Therefore, the percent w-w concentration of the CaCl2 solution is 0.443%.