Answer:
Percent by mass when 40.0 grams of NaCl is dissolved into enough water to make 100. grams of solution is 40% .
Explanation:
Given,
Mass of NaCl = 40 grams
Mass of Solution = 100 grams
In this solution, NaCl is solute and Water is the solvent.
Mass percent of a solution can be calculated using the formula,
Mass percent = (Mass of Solute/Mass of Solution)x(100)
As NaCl is solute, mass of solute = 40 grams
Mass of solution = 100 grams
Substituting the values, Mass percent = (40/100)x(100) = 40%
