So, if I dissolve 1 mg of sugar in 1 ml of alcohol it's a 1000 ppm solution. I don't know what your first language is,but this page is in English.Īnd current English usage is decisively ambiguous.įor mixtures of gases ppm usually refers to mole fraction- but that's because it's (practically) the same as volume fraction.įor solutions it's as often a "shorthand" for mass of solid dissolved in a volume of solvent that would have 999999 times that mass, if the solvent were water. Well, OK, it's wrong- but it was early in the morning, and I had a bus to catch. "take 1 gram of acid and dilute it to a million grams with water" "take 1 gram of acid and dilute it with a million grams of water" I'm sure it's someone's "law" that, when you correct something on the internet you add mistakes of your own. When the abbreviation ppm does not have any additional information to the contrary, that we are talking about the mole fraction. " The unit ppm is also sometimes used as a way to express a fraction of the weight, but usually only in this case specifically inform the writing eg. This concentration is derived from the mole fraction and determines how much chemical compound per 1 million molecules of the solution."
"ppm (parts per million) - way of expressing the concentration of a very dilute solutions of chemical compounds. On my language wikipedia page of ppm, there is said (google translator used):
If you're calculating concentration by using m 1/m 2, you would not even pass exam in our high school. m 1/(m 1+m 2) - concentration of first substance, m 2/(m 1+m 2) - concentration of 2nd substance. You need to dilute with 999,999 to have right proportions. If you dilute 1 gram of substance with 1 million grams of water you won't have 1 ppm (by mass), but less 1/1,000,001. Unless you are dealing with gases the mass/volume interpretation is probably most common and you are wrong. Or, do I take 1 gram of acid and dilute it with a million grams of water, or do I take a millilitre of acid and dilute it with a million millilitres of water?