Question

A solutin contains 100.0 g water, 10.0 g NaCl, and 15.0 g Methanol. What is the Mass Percent of methanol in the solution? The answer is 12.0% but I do not understand why. I know that Mass % = Mass solute/(mass solute + mass solvent) and then the whole thing X 100%. Please help me to see what I am missing in how to correctly solve for these kinds of equations.

Answer 1

Mass percent of methanol :

% mass = mass methanol / mass total

% mass = 15.0   / 100.0 + 10.0 + 15.0

% mass = 15.0 / 125.0

% mass ( methanol ) = 0,12 x 100 = 12%

hope this helps!