Find the percent concentration of a propylene glycol solution by first finding the amount of the compound in solution. The solution is what the solute (in this case, propylene glycol) is mixed with. For this exercise, 7 milliliters (mL) of propylene glycol is mixed in 100 mL of solution.
Divide the solute amount, 7 mL by the solution volume (100 mL). The equation would be 7 mL/100mL.
Solve the problem. 7/100 = .7. Then multiply the .7 x 100 to get the percent concentration, which is 7 percent. So the percent concentration in this particular solution is 7 percent.