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**URGENT PLEASE HELP!! Chemistry Related Math/Hydraulic Problems I Can't Get**

Got a test tomorrow on this stuff. If I know how to attack these problems, I will be ok.

**1. A water plant treats a flow of 9.0 ML/d. the Mix chamber is 0.75m x 0.75m and the depth of water is 1.0m. Flocculation basin is 15m x 5m x 2.5m. What is the flocculation time in minutes?**

**3. The Attempt at a Solution :**

(Answer is 30 minutes)

9.0ML/d = 375kl/h

15 x 5 x 2.5 = 187.5m^3 = 187 000 L

.75x.75x1 = .56m^3 = 560 L

I'd write down what I actually did, but it is nowhere even close. I keep getting numbers much less or wayyyyyy higher.

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**1. the Chlorine demand of a certain water is 3.0mg/L. If the plant operator adds 40lb's of chlorine gas to treat 1.0 million gallons of water, what should be the chlorine residual in mg/L?**

**2. My attempt**

I thought I was right, I still think I am. It says the answers is 1.8 but it just doesn't seem right to me.

CONVERSIONS:

1 000 000 gallons --> 3 785 411.78 L

40 lb ---> 18. 143 kg ----> 18 143 000 mg

18 143 000mg/3 785 411.78 L = 4.79mg/L

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**3. A storage reservoir is 12m wide and 16m high. What is pressure at the bottom of the reservoir, when it is half full?**

**my attempt**

i got it right, but somehow i think it was a fluke.

16m/2 = 8m

8m x 9.81 = 78.9 = 80 kPa(final answer)

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**4. you are required to provide a 2.5mg/L chlorine dosage to water pumped from a well at a rate of 35L/s/ On the well site, you have 200L capacity hypochlorite tank containing 12% chlorine solution. If the feed pump is properly calibrated, how many litres of chemical should be used per hour?**

**my attempt**

Not even worth showing you guys. It is so wrong it is funny. I get a massively high number. The final correct answer is 2.6

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**5. What is the metres of head at the discharge side of the pump that is pumping at a pressure of 93psi?**

**my attempt**

93 x 9.81 = 912 <----- so wrong. answer is actually 65.

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I realize for alot of people these questions are simple. For me, I haven't done this stuff in years and I really don't know how to act these 5 types of problems. However, on the test, these are the types of questions I will get. So if I know how to attack them I will be ok. I hope you people can help me out! Thanks alot