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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: Gotaquestion on March 22, 2020, 11:43:10 AM

Title: Percent change of alcohol and water in a solution
Post by: Gotaquestion on March 22, 2020, 11:43:10 AM

Original solution
Item percent grams
water   50.3%   477.6
98% ethyl alcohol   12.1%   114.8
Vit c   16.9%   160.5
Lecithin granules   20.7%   197.1

But I don't have 98% alcohol so I want to use 40% proof vodka.
How much water and 40% alcohol in grams would I have to use to match the above solution?
I was told this would be the amount below. But I want to double check that it is correct  but can't figure out how the new alcohol and ratio below was derived.

water   26.8%   254.6
40% vodka or spirit   35.6%   337.8
vitamin C   16.9%   160.5
lecithin granules   20.7%   197.1

Title: Re: Percent change of alcohol and water in a solution
Post by: Enthalpy on March 24, 2020, 07:07:54 PM

Checking and deriving the result are two separate operations.

To double-check, take the proportion of the ingredients and their composition. Cumulate all. Compare the results for both recipes.

You can reasonably assume that water makes everything that is not alcohol, in 98% ethyl alcohol and in vodka.

You don't need to compute the vitamin and lecithin, since they're identical in both recipes. So: how much water and ethyl alcohol ?