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# A chemist needs a solution of tannic acid 70% pure. How much distilled water must he add to 5 gallons of acid which was 90% pure to obtain t

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A chemist needs a solution of tannic acid 70% pure. How much distilled water must he add to 5 gallons of acid which was 90% pure to obtain the 70% solution?

Guest Jan 4, 2015

#1
+92221
+5

90% of 5 gallons = 0.9*5 = 4.5 gallons

So the original mixture contains 4.5 gallons of acid and the and 0.5 gallons of water.

Now we need to know 70% of what equals 4.5 gallons

0.70x=4.5

x=4.5/0.7

x=6.4286 gallons (correct to 4 dec places)

6.4285-5=1.4285 gallons

So you will need to add 1.4285 gallons of water.

Melody  Jan 5, 2015
Sort:

#1
+92221
+5

90% of 5 gallons = 0.9*5 = 4.5 gallons

So the original mixture contains 4.5 gallons of acid and the and 0.5 gallons of water.

Now we need to know 70% of what equals 4.5 gallons

0.70x=4.5

x=4.5/0.7

x=6.4286 gallons (correct to 4 dec places)

6.4285-5=1.4285 gallons

So you will need to add 1.4285 gallons of water.

Melody  Jan 5, 2015

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