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  • ppm to mg/L conversion

    I am trying to convert the following ppm to mg/L.

    (1,667.4 ppm with a Density of 1.0733) and (1.043.7 ppm with a density of 1.0975 ). I am multipying the density by the ppm to achieve my mg/L number? What is the correct formulation or even better, the answer to the problems above? Thanks!

  • #2
    Re: ppm to mg/L conversion

    Hi, ppm IS mg per liter.

    Comment


    • #3
      Re: ppm to mg/L conversion

      Originally posted by cajunbred
      I am trying to convert the following ppm to mg/L.
      Inorder to conversion note below:

      ((molecular weight)/22400)*ppm=mg/l

      Comment


      • #4
        mg/L conversion

        how do you convert mg/L P to mg/L PO4? why are results generally reported as mg/L P?

        Comment


        • #5
          Re: mg/L conversion

          Originally posted by Unregistered
          how do you convert mg/L P to mg/L PO4? why are results generally reported as mg/L P?
          Hi, the molar mass (Mr) of phosphate is 31 + 4 x 16 = 95g/mol, the Mr of phosphorus is 31g/mol.

          To convert ppm P to ppm PO4, multiply by 95/31.

          For example if you have 50mg/L P, in a phosphate solution, this is the same as 50 x 95/31 = 153mg/L PO4.

          However, PO4(3-) doesn't exist on its own, it would be H3PO4 for example, or Na3PO4.12H2O. Also, it might be present as phosphite, rather than phosphate, or some other ion mixture.

          Hope this helps.

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          • #6
            Re: ppm to mg/L conversion

            You probably realise anyway, but ppm and mg/L are the same thing when you are talking about solutions.

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            • #7
              Re: ppm to mg/L conversion

              Mrs. X
              ppm is not necessarily mg/L. It IS mg/kg.
              If the solvent is water (1L of water weighs 1 Kg), then mg/L = ppm

              Comment


              • #8
                Re: ppm to mg/L conversion

                The convention is, and always has been, that if you are talking about wet chemistry, concentrations are reported as w/v (weight for volume) unless otherwise stated.

                (JohnS HATES this, and wants to have concentrations stated as mg/L or mg/kg. He will delighted to have converted you.)

                Comment


                • #9
                  Re: ppm to mg/L conversion

                  Originally posted by Mrs X View Post
                  The convention is, and always has been, that if you are talking about wet chemistry, concentrations are reported as w/v (weight for volume) unless otherwise stated.

                  (JohnS HATES this, and wants to have concentrations stated as mg/L or mg/kg. He will delighted to have converted you.)
                  HATE is a little strong but I do find ppm ambiguous. By the time you add qualifiers for weight/weight, weight/volume, moles/moles, volume/volume, it is just as easy to use real units.

                  I acknowledge your use in laboratory chemistry, but industrial chemicals (and chemical engineering) are usually on a weight/weight basis.

                  Comment


                  • #10
                    Re: ppm to mg/L conversion

                    Acceptable limit for nitrate, often found in well water in agricultural areas is 10ppm. If a water sample is found to contain 350 mg/L, does it meet the acceptable limit? Show a calculation to support your answer. Show the steps of getting to the answer.

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                    • #11
                      Re: ppm to mg/L conversion

                      Originally posted by Jmusfreshest View Post
                      Acceptable limit for nitrate, often found in well water in agricultural areas is 10ppm. If a water sample is found to contain 350 mg/L, does it meet the acceptable limit? Show a calculation to support your answer. Show the steps of getting to the answer.
                      This is a dilute solution in water, so the answer is the same whether the ppm is stated on weight/weight or volume/weight basis (in case you read the slight dispute above). The well water is VERY close to the density of pure water and almost certainly cool enough that the density is close to 1 kg/L

                      Therefore 350 mg/L is approx 350 mg/kg, and therefore 350 ppm. Therefore it is 35X the limit.

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                      • #12
                        Re: ppm to mg/L conversion

                        hi. i want to make 240000ppm salt water.how many grams of pure NaCl must be solved in 1 liter of water?
                        thanks

                        Comment


                        • #13
                          Re: ppm to mg/L conversion

                          Originally posted by Unregistered View Post
                          hi. i want to make 240000ppm salt water.how many grams of pure NaCl must be solved in 1 liter of water?
                          thanks
                          If you take 240g of salt, dissolve it in a bit of warm water, then cool the mixture to room temperature, you will be able to make the solution up to 1L with stiring. This will be a 240,000ppm w/v solution. Also called 24%w/v.

                          Salt solutions that are this concentrated don't behave very well, they try to deposit salt dendritically over everything that the solution comes in contact with. You will get salt deposited up the sides of the flask or bottle that you keep it in even. Just warning you.

                          Now for the interesting bit, why on earth do you want such a concentrated salt soution? - That has to be more interesting than how to make it!

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                          • #14
                            Re: ppm to mg/L conversion

                            Hi so am i correct in saying that 80mg would = 80ppm?

                            because i need to work this out...

                            I have 80mg of caffeine in a tablet that wieghts 4g.....so would that mean that there is 80ppm of caffeine in it??

                            Comment


                            • #15
                              Re: ppm to mg/L conversion

                              Originally posted by Unregistered View Post
                              Hi so am i correct in saying that 80mg would = 80ppm?

                              because i need to work this out...

                              I have 80mg of caffeine in a tablet that wieghts 4g.....so would that mean that there is 80ppm of caffeine in it??
                              ppm in this case would be mg/kg. You have to work out how much caffine would be in 1kg of tablets. (There are 1000g in 1kg). Hopefully you can see there would be much more than 80ppm.

                              If this a homework question, do you want to work it out your self? - You can write the answer back here for a check if you like.

                              Comment

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