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Doreen Schmidt is a chemist. She needs to prepare 32 ounces of a 12% hydrochloric acid solutionFind the amount of 16% solution and the amount of 8% solution she should mix to get this solution

Doreen Schmidt is a chemist She needs to prepare 32 ounces of a 12 hydrochloric acid solutionFind the amount of 16 solution and the amount of 8 solution she sho class=

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tianaahayes
ANSWER: 16 ounces of the 11% solution and 12 ounces of the 7% solution should be used.

Explanation: Let x be the number of ounces of the 14% solution and 28 - x be the number of ounces of the 7% solution.

The equation you must set up shows the number of ounces of acid added from each solution equals the number of ounces in the 11% solution.

The key thing to remember is that the number of ounces of acid is the amount of solution times the concentration of acid it contains.

Thus,

.11x + .07(28-x) = .11(28).

You can solve this in the usual way, but it helps to clear the decimals by multiplying both sides by a suitable number.

So here goes,

.14x + 1.96 - .07x = 3.08

Multiply both sides by 100:

14x + 196 - 7x = 308.

Now finish solving:

7x = 308 - 196 = 112
x = 112/7 = 16

Then 28-x = 28 - 16 = 12.

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