Explanation:
We have to find the % by mas of a solution containing 15.0 g of NaCl in 60.6 g of water.
The percentage by mass of a solution can be calculated using the following formula.
% by mass = mass of solute/mass of solution * 100
We already know the mass of solute (15.0 g of NaCl) but we still have to find the mass of the solution.
mass of solution = mass of solute + mass of solvent
mass of solution = 15.0 g + 60.6 g
mass of solution = 75.6 g
Finally we can find the answer to our problem.
% by mass = mass of solute/mass of solution * 100
% by mass = 15.0 g/(75.6 g) * 100
% by mass = 19.8 %
Answer: The percentage by mass of this solution is 19.8 %.
