A percent w/v solution is calculated with the following formula using the gram as the base measure of weight (w):
% w/v = g of solute/100 mL of solution
Example 1:
Physiologic or isotonic saline is a 0.9% aqueous solution of NaCl.
0.9% saline = 0.9 g of NaCl diluted to 100 mL of deionized water, where NaCl is the solute and deionized water is the solvent.
Example 2:
What is the % w/v of a solution that has 7.5 g of sodium chloride diluted to 100 mL with deionized water?
By definition, a percent w/v solution is the measure of weight per 100 mL: 7.5 g/100 mL = 7.5%
You can calculate this value as well:
X % = 7.5 g NaCl / 100 mL of solution
X/100 = 7.5 / 100
Cross multiplying, 100X = 750
X = 7.5% w/v
