Creating dilutions reduces the concentration of one liquid with the addition of another. In order to create 70 percent isopropyl alcohol, a solution of isopropyl alcohol with a concentration greater than 70 percent must be diluted by a calculated amount of water. The formula for this calculation is C1V1=C2V2, where C1 and V1 is the starting concentration and volume of the solution and C2 and V2 is the final concentration and volume of the dilution. For the purpose of this example, the initial solution is 100 percent isopropyl alcohol, creating a final volume of 500 mL of 70 percent isopropyl alcohol.
Things You'll Need
- Protective eye goggles
- 100 percent Isopropyl alcohol
- 500 mL graduated cylinder
- Glass stirring rod
Put on protective goggles and gloves before working with any liquids.
Identify the initial concentration of the 100 percent isopropyl alcohol, which is the C1 variable in the equation. The variable C1=100.
Determine the desired concentration and volume of the final solution to obtain C2 and V2. In this instance the final concentration C2 is 70 percent and final volume V2 500 mL; So C2=70 and V2=500.
Solve the equation C1V1=C2V2 for the unknown variable of V2. Substitute known variables: 100V1=70500, V1=35000/100, V1= 350. It is determined that 350 mL of 100 percent alcohol is needed for the preparation.
Add 350 mL of 100 percent isopropyl alcohol to a 500 mL graduated cylinder. Ensure that the measurement is read at eye level with the meniscus, the bottom of the curved liquid, at 350 mL.
Add an additional 150 mL of water to the graduated cylinder for a total volume of 500 mL, again measured at eye level.
Pour remaining solution into a new beaker marked 70 percent isopropyl alcohol and stir with a glass rod.
- Photo Credit Jupiterimages/Photos.com/Getty Images Jupiterimages/Comstock/Getty Images
What Is Isopropyl Rubbing Alcohol?
Alcohols are a class of organic compounds, one of which is isopropyl alcohol, (CH3)2CH2OH, also called rubbing alcohol, isopropanol or 2-propanol (the...
Ethanol vs. Isopropyl Alcohol to Disinfect
Ethanol and isopropyl alcohol are both members of the alcohol family and have similar disinfectant properties. Ethanol is the type of alcohol...
How to Make Isopropyl Alcohol
Isopropyl alcohol, also known as isopropanol, is a colorless, flammable organic compound with the molecular formula C3H8O. This liquid substance has a...
How to Calculate Dilution Solutions
A dilution solution contains solute (or stock solution) and a solvent (called diluent). These two components proportionally combine to create a dilution....
How to Remove Water From Isopropyl Alcohol
You can separate isopropyl alcohol and water using heat and a distillation apparatus. Since isopropyl alcohol has a lower boiling point than...
How to Make E85 Gas
E-85 is an alternative fuel that is a mixture of 85 percent ethanol and 15 percent unleaded gasoline. Individuals who want to...