How much water must be added to 42.0 g of CaCl₂ to produce a solution that is 40.0 wt% CaCl₂? A)56.7 g B)63.0 g C)16.8 g D)120 g

Question

Quizplus · Accepted Answer

The initial mass of CaCl2 is 42.0 g, and we want to produce a 40.0% solution. Therefore, the mass of the final solution will be:
mass_final = mass_CaCl2 + mass_water
mass_final = 42.0 g + mass_water
We want the final solution to be 40.0% CaCl2 by weight. This means that the mass of CaCl2 in the final solution will be:
0.40 mass_final = 0.40 (42.0 g + mass_water) = 16.8 g + 0.40 mass_water
We can now set up an equation to solve for the mass of water that needs to be added:
0.40 mass_final = 16.8 g + 0.40 mass_water
0.40 (42.0 g + mass_water) = 16.8 g + 0.40 mass_water
16.8 g = 0.60 mass_water
mass_water = 28.0 g
Therefore, the answer is B) 63.0 g (42.0 g CaCl2 + 28.0 g H2O).

How Much Water Must Be Added to 42