Answer:
34.93 g of KCl
Step-by-step explanation:
To solve this problem, we can use the definition of percent by mass:
percent by mass = (mass of solute / mass of solution) × 100%
We are given the volume of the solution and the percent by mass, as well as the density of the solution. We can use the density to find the mass of the solution:
mass of solution = density × volume
mass of solution = 1.15 g/mL × 220 mL
mass of solution = 253 g
We want to find the mass of solute (potassium chloride, KCl) required to make this solution. Let's assume that x is the mass of KCl needed.
mass of KCl / mass of solution = 13.8%
mass of KCl / 253 g = 0.138
mass of KCl = 0.138 × 253 g
mass of KCl = 34.93 g
Therefore, we need 34.93 g of KCl to make 220 mL of a 13.8% by mass solution with a density of 1.15 g/mL.