How many grams of solute are contained in 95.0 ml of a 1.80% "weight by weight" solution?
A "weight by weight" solution is a mixture in which the concentration is measured as the ratio of the mass of the solute in grams divided by the volume of the solution measured in milliliters expressed as a percent, assuming that the solvent is water (density of 1g/mL).
The formula is (%W/W) = grams solute/volume of solution.
To determine the mass of the solute you must do a step of algebra and isolate the variable for mass:
grams of solute = (%W/W)x volume of solution
Before we can do the calculation we must also convert the percent to a decimal.
grams of solute = 0.0180 X 95.0 = 1.71 grams.