producing dilutions reduce the concentration that one liquid v the enhancement of another. In bespeak to develop 70 percent isopropyl alcohol, a solution of isopropil alcohol with a concentration greater than 70 percent have to be diluted by a calculated amount of water. The formula because that this calculation is C1_V1=C2_V2, where C1 and also V1 is the starting concentration and also volume of the solution and also C2 and also V2 is the last concentration and volume that the dilution. For the purpose of this example, the initial systems is 100 percent isopropyl alcohol, producing a last volume the 500 mL the 70 percent isopropil alcohol.

You are watching: How to make 70% ethanol

Identify the early stage concentration the the 100 percent isopropil alcohol, which is the C1 change in the equation. The variable C1=100.

Determine the preferred concentration and volume the the final solution to attain C2 and also 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 C1_V1=C2_V2 for the unknown variable of V2. Substitute recognized variables: 100_V1=70_500, V1=35000/100, V1= 350. The is identified that 350 mL of 100 percent alcohol is required for the preparation.

Add 350 mL of 100 percent isopropyl alcohol come a 500 mL i graduated cylinder. Ensure the the measure up is check out at eye level with the meniscus, the bottom that the curved liquid, at 350 mL.

Add secondary 150 mL the water come the i graduated cylinder because that a complete volume the 500 mL, again measured in ~ eye level.

Pour staying solution right into a brand-new beaker significant 70 percent isopropyl alcohol and also stir with a glass rod.

The formula C1_V1=C2_V2 may be applied to any dilution as lengthy as there room at least three recognized variables, and also the early concentration is higher than the final concentration.

See more: How To Fill In A Tattoo : An Epic Step By Step Guide To Tattooing

whenever working with hazardous substances, wear appropriate protective equipment to protect the eyes and skin. Closed footwear should constantly be worn.

Julie Revel, a former neurobiologist in pharmaceuticals, began writing professionally in 2009 v a emphasis on wellness and condition prevention. Based in brand-new Jersey, she functions as a clinical writer in the healthcare industry. Revel graduated from attracted University with a B.A. In neuroscience and also is right now pursuing her medical professional of clinical Humanities.