[kerilynn]

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?


also this one 2

[Kyle1990]

ppm=1gram of solute/1.0X10^6 grams of solution. Considering as to how 1 liter of water = 1 kg, you can interchange mass and weight. Because the numbers we are dealing with are so small, it is safe to say that the 100.0 L of water = 100.0 Kg of solution.

From there it's a simple ratio:

(0.5g)/(1.0X10^6g)=(x)/(100,000g)

x=5 grams of chlorine

[meenu]

concentration  = PARTS PER MILLION = 0.5 ppm
1 *10^6 grams of water has  0.5 grams of cl
    1000 Kg  of water has 0.5 grams of cl                  ( 10^ 6 grams = 1000 kg)
1 Kg of water has  0.5 / 1000 = 0.0005 grams of cl

density of water = 1 Kg / litre
mass = volume * density
mass of 100 litre of water = 100 L  * 1 Kg/L = 100 Kg

 so 100 Kg of water has  0.0005 * 100 = 0.05 grams of cl

[enahs]

Man, people sure do make Parts Per notation really complicated when it is easy.


PPM =  Mass of Solute * (10⁶)
           Mass Solvent

PPB is (10⁹)

Mass Percent = PPH (Part Per Hundred) is (10³)

So, if I have 0.5 PPM, multiply by the mass of the solvent and divide by a million. Your masses need to be in the same unit, but that is then easily converted.

[sjb]

Man, people sure do make Parts Per notation really complicated when it is easy.
...
PPB is (10⁹)

Not all the time, sometimes a billion is 10¹², even more so in scientific contexts.

Mass Percent = PPH (Part Per Hundred) is (10³)

mass percent would be 10², no?

S

[enahs]

mass percent would be 102, no?

Doh. You got me. My bad. Good catch.

Not all the time, sometimes a billion is 10¹², even more so in scientific contexts.

What?
A billion is a 1 followed by 9 zeros. Period. Scientific or not. That is how it is defined. With 12 zeros behind it, it is a trillion.

[macman104]

A billion in the U.K. is a million million not a thousand million.

[enahs]

That is new to me!


If the NIST says it is 10⁹, then that is what I am going with.

That is actually more silly then the US using the stupid English system and not the metric. I mean, you guys use the metric but then decided to do it differently then everywhere else in the world. Just crazy.

[DrCMS]

That is new to me!

So go and read up on the subject rather than talk rubbish about it.

http://en.wikipedia.org/wiki/Long_and_short_scales

[jansenwrasse]

1 part per million is 1 milligram per liter or 1 mg/L  I use this more often than any of the other formulas personally.

Hope it helps you

[DrCMS]

1 part per million is 1 milligram per liter or 1 mg/L  I use this more often than any of the other formulas personally.

Hope it helps you

No it does not, this ONLY applies to dilute aqueous solutions it is not some kind of universal truth.  As a short cut if you know when it can be used fine use it but do not quote it as a formula for everyone to blindly follow.