Final answer:
To create a 35.0% BaCl2 by mass solution, one must add 37.7143 g of water to 43.0 g of BaCl2.
Step-by-step explanation:
To calculate how much water must be added to 43.0 g of BaCl2 to produce a solution that is 35.0 percent BaCl2 by mass, we can use the mass/mass percent formula:
mass percent = (mass of solute / mass of solution) x 100%
Here, BaCl2 is the solute, and we need to find the mass of the water (solvent) required. Given that the mass of the solute (BaCl2) is 43.0 g and the desired mass percent is 35.0%, we can set up the equation:
35.0 = (43.0 g / (43.0 g + mass of water)) x 100%
Solving for the mass of water:
mass of water = (43.0 g / 0.35) - 43.0 g = 80.7143 g - 43.0 g = 37.7143 g
Therefore, 37.7143 g of water must be added to 43.0 g of BaCl2 to achieve a 35.0% BaCl2 by mass solution.