i dont understand how to do this

[shay]

this is my mid term and idk how to do any of these problems

 

1) A 500 ml aqueous solution contains 0.005 mg of arsenic. What is the concentration of arsenic in terms of ppb?

 

 

 

2) How many feet of water (depth) are in an open reservoir 80 ft. in diameter if the pressure at the bottom outlet is 50psi?

 

 

 

3) What is the detention time of a settling tank with a 40 ft. diameter and a side water depth of 15 ft. with a flow of 10,000 gpd ?

 

 

4) Determine the BOD 5 for the following.

 

Initial DO = 9.6 mg/L

 

5 Day DO = 4.3 mg/L

 

Sample Volume = 5 mL

 

 

 

5) What is the hydrostatic pressure at a customer’s tap located 110ft above the main when

 

the pressure in the water main is 80 psi?

 

 

6) Determine the TDS for the following.

 

Clean filter weight = 455 mg

 

Filtered weight = 515 mg

 

After ignition weight = 495 mg

 

Sample size = 100mL

 

 

7) What would the total expected daily water demand be for a small town of 18,750 people? (express in mgd)

 

 

 

 

 

[Psycho]

this is my mid term and idk how to do any of these problems

 

1) A 500 ml aqueous solution contains 0.005 mg of arsenic. What is the concentration of arsenic in terms of ppb?

 

 

1) Turn both the liquid and weight amounts to Moles then times by avogadro's number before dividing the number of arsenic molecules by the number of water ones and changing to the correct units.

Edited October 13, 2011 by Psycho

[InigoMontoya]

So let me get this straight....

 

You want us to do your midterm exam for you?

 

There's a thing called "integrity." You might see if you can buy some on ebay because you apparently don't have any (and you desperately need some).

 

In other words: GFY.

Edited October 13, 2011 by InigoMontoya

[mooeypoo]

!

Moderator Note

Guys, I remind you, we are not here to give out answers, we're here to help people find their own way to a solution. Shay, you have to show us that you are trying and what you think you should do, and we might be able to help steer you the right way.

That said, I can't say I'm too happy about the fact you stated this is a midterm, but regardless, we would have done the same whether this is a midterm or homework. Show work, tell us where you got stuck or there's nothing we can do.

Moved to HW help