Percent Weight in Volume: % w/v

The definition of percent weight in volume:

"The % w/v of any component is the number of grams of that
component contained in 100 cm³ (or 100 ml) of the total product."

leads to the following equation:

You need to be able to calculate all three parts of this equation
given two of the others ie you need to be able to calculate:

This part of the equation shows what proportion 100 cm³ is of the total volume of solution present.

Once you know this proportion, you know that the same proportion of the total mass of component can be found in 100 cm³.

% w/v = mass of solute x                100                  (g/100 cm³)
volume of product

For example. Suppose 300 cm³ of a solution contains 9 grams of solute.
100 cm³ is one third of the total volume present.
Thus 100 cm³ must contain one third of the total mass of solute present ie 3 grams.
Thus the concentration of the solute is 3 g/100 cm³ ie 3 % w/v

Click to Continue