Calculate the percent by mass when 40.0 grams of NaCl is dissolved into enough water to make 100. grams of solution.

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%