SOLUTION: Travis Hayes needs 10% hydrochloric acid for a chemistry experiment. How much 5% acid should be mixed with 60 mL of 20% acid to get a 10% solution? acrown1@umbc.edu

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Question 44269: Travis Hayes needs 10% hydrochloric acid for a chemistry experiment. How much 5% acid should be mixed with 60 mL of 20% acid to get a 10% solution?
acrown1@umbc.edu
Answer by mbarugel(146) (Show Source):
You can put this solution on YOUR website!
Hello!
The acid percentage of the mix will be given by the formula:
(Amount of X/Total Amount)*(%acid in X) + (Amount of Y/Total Amount)*(%acid in Y)
In your case, let's call Y to the 20% acid. We know that you have 60 mL of this. Let's call X to the amount we need to add of the 5% acid.
Once we add it, the total amount will clearly by (60 + X) mL. Therefore, using the formula I gave above, we get the equation:

We now have to solve for X. Let's multiply both sides of the equation by (60+X) in order to get rid of the X's in the denominator:

We conclude that you need to add 120 mL of the 5% acid.

I hope this helps!
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