To find the mass of water required, we need to calculate the mass of the KCl salt in the solution.
Step 1: Convert the percentage concentration to a decimal by dividing it by 100:
9.25% = 9.25/100 = 0.0925.
Step 2: Calculate the mass of KCl in the solution by multiplying the percentage concentration by the total mass of the solution:
Mass of KCl = 0.0925 x 100.0 g = 9.25 g.
Step 3: Since the mass of the solution is equal to the mass of KCl + mass of water, we can subtract the mass of KCl from the total mass of the solution to find the mass of water:
Mass of water = Total mass of solution - Mass of KCl = 100.0 g - 9.25 g = 90.75 g.
Therefore, the mass of water required to prepare the 9.25% KCl solution is 90.75 grams.