ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: Phantom-II on February 26, 2012, 05:13:54 pm
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Got a question that asks for grams per 1g of water, and the concentration is 0.9 ppm
what exactly does parts per million mean? and how do i use it/convert between mol/L and g/L?
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It's just another way of saying mg L-1, i.e. one gram amongst a million.
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It refers to having 1 part among 1 million parts e.g.
1 microgram in 1 million micrograms
= 1 microgram in 1 gram
= 1 microgram in 1 millilitre
= 1 milligram in 1 litre
etc.
You just have to remember if you multiply one quantity by a certain amount, you have to do so to the other as well.
edit: same as what Nobby said.
So in your example it is 0.9 ppm instead of 1.0 ppm, so there would be 0.9 micro grams in 1 million micro grams, which is the same as 0.9 micro gram in 1 gram etc.
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okay, the questions says 0.9ppm fluorine ions, what is mol per 1g of water?
so then, 0.9ppm would mean, theres 0.9grams in 10^6 grams? so i would divide by 10^6 and divide by molar mass of fluorine?
lol this gave me the right answer, thanks for the help!
so with ppm/b, the measure untis can be w.e we want, and interchangeable? as in,
g/million g,
mL/million mL,
1g/10^6g = 1ml/10^ml?
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okay, the questions says 0.9ppm fluorine ions, what is mol per 1g of water?
so then, 0.9ppm would mean, theres 0.9grams in 10^6 grams? so i would divide by 10^6 and divide by molar mass of fluorine?
lol this gave me the right answer, thanks for the help!
so with ppm/b, the measure untis can be w.e we want, and interchangeable? as in,
g/million g,
mL/million mL,
1g/10^6g = 1ml/10^ml?
1g = 1mL for water only, AFAIK (could be wrong)
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yes they are all interchangeable.
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okay, thanks a lot guys!