3 replies to this topic

[humphry]

Hi,

I am trying to figure out how to use 'liter^-1', as in 2 gram/liter^-1 (2 gl^-1).  I know if the ratio was 2 g/l the resulting ppm would be 2000, but I do not know how to use the negative exponent.  If someone could explain the process or offer an equation/formula I would be most grateful!  I would like to convert the solution to g/l (or mg/l) so I can calculate the ppm.

If I calculate l^-1 I get 1000m^-3, which I do not see as being useful.  I am trying to figure out how to mix two different substances: CaCl2 @ 8 g/l^-1 and alkyl polyglucoside @ 2 g/l^-1.  For a donor solution (I think that is the right term?) I am going to use one liter of deionized water for mixing the CaCl2.  To that mix I will add chelated Ca and chelated Mg along with phosphorus salts (anions).

P.S. This is not homework, I am in college but this is something I am working on by myself as a hobby.

Thank you for you any help

Edited by humphry, 07 April 2009 - 06:00 PM.

[bob1]

The answer depends on the solvent... if it is water (1 g/cm³) then you will have 2 parts per 1000 or 2000 parts per million, however if the solvent has a density less than or greater than water the answer will be different.

With gases the problem becomes harder requiring mol fractions and molecular masses etc.

Quote

2 gram/liter^-1 (2 gl^-1)

??? use the sub and sup commands e.g. [command] text [/command] to write this properly

gl[sup]-1[/sup]

will give you gl^-1.  Besides which, grams per litre per litre as you wrote the first instance is a nonsensical unit.

[humphry]

Hi,  

bob1, on Apr 8 2009, 02:14 AM, said:

The answer depends on the solvent... if it is water (1 g/cm³) then you will have 2 parts per 1000 or 2000 parts per million, however if the solvent has a density less than or greater than water the answer will be different.

Thanks for your response.  Yes the solvent is deionized water, I mentioned that in my first post but I called it the 'donor solution' which I assume is an incorrect term?  I thought maybe it should have been called 'receiver solution', thanks for clearing that up for me.

Are you saying 2 g/l^-1 is the same as 2 g/l, and both equal 2000ppm?  How is this so?  I knew that 2 g/l was 2000ppm, but how can 2 g/l^-1 be 2000ppm?

How does on calculate the weight of 2 g/l^-1 (CaCl2/deionized water)?  How many grams per liter does 2 gl^-1 equal?  My problem is I do not know how to use liter^-1...

bob1 said:

humphry said:

2 gram/liter^-1 (2 gl^-1)

??? use the sub and sup commands e.g. [command] text [/command] to write this properly

gl[sup]-1[/sup]

will give you gl^-1.

The use of the carrot is correct as far as I understand, as is the use of x².  Using the carrot is more difficult to read but easier to type.

bob1 said:

Besides which, grams per litre per litre as you wrote the first instance is a nonsensical unit.

Nowhere did I write g/l/l.  I wrote "2 gram/liter^-1 (2 g/l^-1)" for the sake of clarity, which I guess I did not achieve (there is a space between the amount and the first parenthesis).

Thank you for your assistance

Edited by humphry, 08 April 2009 - 10:45 AM.

[bob1]

I was assuming that you had made a mistake in your post and was meaning to write g/l or gl^-1.  Google calculator has 1 gram / (litre^(-1)) = 1.0 × 10^-6 m³ kg or equivalent to 1 ml = 1 gram, or equivalent to g/l

Writing g/l is equivalent to writing gl^-1, OK?  Therefore, writing g/l^-1 is equivalent to writing g/l/l or gl^-2 in terms of mathematics, though I must be wrong there. I was assuming that you had made a mistake in your post and was meaning to write g/l or gl^-1

Your use of the carrot is correct, I just thought you had confused yourself.