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Topic: calculating parts per million  (Read 5119 times)

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Offline kerilynn

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calculating parts per million
« on: July 21, 2008, 10:15:10 AM »
most community water supplies have 0.5 ppm of chlorine added for purification. What mass of chlorine must be added to 100.0 L of water to achieve this level?


I dont understand how to do this because on all the other problems i am looking for the PPM here i have it . can anyone please walk me all the way through this ... PLEASE ASAP
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Offline DrCMS

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Re: calculating parts per million
« Reply #1 on: July 21, 2008, 10:30:38 AM »
I assume this is parts by weight rather than volume or moles.

So 1 ppm = 1g of chlorine per million g of water
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Offline kerilynn

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Re: calculating parts per million
« Reply #2 on: July 21, 2008, 10:33:24 AM »
no the answer in the back of my book is 5 X 10 ^ -2 g Cl2 but i dont know how in the world they got this!11
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Offline DrCMS

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Re: calculating parts per million
« Reply #3 on: July 21, 2008, 10:37:56 AM »
Quote from: kerilynn on July 21, 2008, 10:33:24 AM
no the answer in the back of my book is 5 X 10 ^ -2 g Cl2 but i dont know how in the world they got this!11

They did the maths is how.  I'm not just going to give you the answer.

Look i've just read through your other posts and you need to stop just posting question expecting other people to do your homework for you.

Stop being so lazy.
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Offline macman104

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Re: calculating parts per million
« Reply #4 on: July 21, 2008, 11:50:35 AM »
Not to mention it's already been posted once before

http://www.chemicalforums.com/index.php?topic=27587.0
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Offline enahs

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Re: calculating parts per million
« Reply #5 on: July 21, 2008, 07:05:16 PM »
Use the real definition of PPM and do the simple math.

PPM =  Mass of Sample * (106)
          Mass of Solvent


You know everything but "Mass of Sample". Solve for it.
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