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70% glycolic solution
Hey I’m very bad at math (I have dyscalculia) and I need help understanding the math behind getting a 5% or 10% addition to my formula with like a 70% solution or 80% solution. I just finished school but I still need help in this area.
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6 Replies
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X*.7=.05
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Have you considered M1V1 = M2V2?
Using the the 70% solution and a 5% addition, your M1 is 70%, your M2 is 5%, and V2 is you total amount after mixing. Using those three numbers, you can calculate V1, the amount of 70% solution to be added.
To get V1, multiply V2 by 5% and divide the answer you get by 70%.
I hope this gives a rough estimate. -
@ngarayeva001 & @biofm Just remind me the formula we learn the basic chemistry. But, it just calculate the concentration of glycolic acid. what formula is used to calculate the pH of 5% and 70%?
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Sorry everyone. Thank you for these replies but I still don’t understand
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I am not a chemist. I am not great at math. Maybe I can help.(Note: I am not suggesting that anyone do this, it is just an example on how I
do the math. I am more comfortable using this incredibly roundabout way
because it is simple and easy to remember how to do. I apologize to any
chemists reading this. I know that it is especially bad because it is
about an acid and the original version is probably a v/v not w/w
solution.)Does it help to think of it as a solution where 1 arbitrary unit, like a gram, of this solution is 0.7 glycolic acid plus 0.3 water?So if you use 10 grams of this solution, 7 of that is glycolic acid and 3 is water.If you put 10 grams of this 70% glycolic solution into a bottle, and you add 90 grams of water to it, you’d have 7 grams of glycolic acid in 93 grams of water, or a 7% glycolic acid solution.If you needed some other amount of a 70% solution as an active percentage in the final product, say 5%, there’s probably a better way to do it, but what I do is get out a calculator and start putting in numbers. To get the active amount you take a number and multiply it by 0.7.So to get a 5% active solution from a 70% active solution, I started with 8 x 0.7, which is 5.6That’s too much, so then I tried 7.5 x 0.7 = 5.25Closer, but still too much so 7.25 x 0.7 = 5.075Ok, then 7.15 x 0.7 = 5.005If I really wanted to play it safe, 7.1 x 0.7 = 4.97So to make 100 grams of a 5% solution using a 70% solution, I’d use 7.15 grams of the 70% solution and 92.85 grams of water and end up with 5 grams of glycolic acid in 95 grams of water.This method works better with less scary ingredients. Like 70% sorbitol liquid.But I hope that it helps with the math or thinking about the math. -
@AnnaUnce, I think you might be overcomplicating it. To get 5% of active out of 70% solution you simply divide 0.05 to 0.7. To get 10% out of 80% solution you divide 0.1 to 0.8.
x*concentration of your solution = % of the active ingredient in the formula.
x*0.7=0.05
x=0.05/0.7 = 7.14% of 70% solution is needed to achieve 5% concentration of active ingredient in the formula.Put it in MS Excel for simplicity.
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