SOLUTION: Peter has 100ml of 40% citric acid on hand. The photo developer requires 500ml of 2% citric acid solution. How would he make it?

Question 971516: Peter has 100ml of 40% citric acid on hand. The photo developer requires 500ml of 2% citric acid solution. How would he make it?
Found 2 solutions by Boreal, josgarithmetic:
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
100 ml *(.40) citric acid =40 ml pure citric acid.
500 ml of 2% citric acid is 500 ml (.02) citric acid and is 10 ml pure citric acid
He needs 25 ml of the 40% citric acid and enough water to make 500 ml.
He is diluting it from 40% to 2%, which is 20 fold.
He needs 20 fold water.
500 ml/25 ml =20 fold dilution.
Answer by josgarithmetic(39617) (Show Source): You can put this solution on YOUR website!

v is how much of the 2% acid to add.
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