SOLUTION: how much pure acid should be added to 18 L of 30% acid to increase the concentration of 50% acid?

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Question 400956: how much pure acid should be added to 18 L of 30% acid to increase the concentration of 50% acid?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
how much pure acid should be added to 18 L of 30% acid to increase the concentration of 50% acid?
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Equation:
acid + acid = acid
0.30*18 + 1*x = 0.50(18+x)
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Multiply thru by 100 to get:
30*18 + 100x = 50*18 + 50x
50x = 20*18
x = (2/5)(18)
x = 36/5 = 7 1/5 L (amt of pure acid needed)
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Cheers,
Stan H.