SOLUTION: a lab tech needs to make a 126-liter batch of a 20% acid solution, how can the lab tech combine a batch od an acid solution that is oure acid with another that is 10% to get desire
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Question 1025825: a lab tech needs to make a 126-liter batch of a 20% acid solution, how can the lab tech combine a batch od an acid solution that is oure acid with another that is 10% to get desired concentration Found 2 solutions by josmiceli, FrankM:Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website! Let = liters of pure acid needed
Let = liters of 10% solution needed
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(1)
(2)
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(2)
(2)
Subtract (1) from (2)
(2)
(1)
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and
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14 liters of pure acid are needed
112 liters of 10% solution are needed
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check:
(2)
(2)
(2)
(2)
(2)
OK
You can put this solution on YOUR website! I prefer to teach this with the single variable method.
X is the amount of pure acid needed
126-X is the 10% solution needed.
You see, this eliminates the need for 2 variables, since we know they add to 126, both amounts are expressed in terms of each other.
100X+10(126-X)=20(126)
100X+1260-10X=2520
90X=1260
X=14
14 liters pure acid
112 liters 10% acid containing 11.2 liter acid.
total 25.2liters of acid in 126 liters solution is 25.2/126 = 20%
