Chris_H Posted August 12, 2022 Share Posted August 12, 2022 I have a LAQUAtwin Salt 11 which has a NaCl mode and ranges from 0ppt to 100ppt (or 0% to 10.00%). I am wanting to work out the Na concentrations from the NaCl and I want to convert the Na component to Milli-equivalents per litre. I can't seem to find any information on the net to help me. Could anyone please help educate me with a worked example please? I would really really appreciate it. Thanks for looking and my kindest regards to all. newbie Chris Link to comment Share on other sites More sharing options...
chenbeier Posted August 12, 2022 Share Posted August 12, 2022 (edited) 1 ppt = 1 ng/ kg NaCl molar weight is 58,5 g/ mol, Na molar weight 23 g/ mol The ratio is 1 g NaCl is equal to 0,39 g Na So 1 ppt NaCl is 0,39 ppt Na = 0,39 ng/kg Na 100 ppt correspond to 39 ng/kg For the volume you need specific gravity of the solution. Probably with this low concentratian it's 1 g/ml Edited August 12, 2022 by chenbeier Link to comment Share on other sites More sharing options...
Chris_H Posted August 13, 2022 Author Share Posted August 13, 2022 thanks heaps chenbeier 😀 that clears the first part up. So how do convert the Na measurement to cmol/L. for example: Let say from a 50ml water solution with NaCl dissolved into it, I get a 100 ppt NaCl of which 0.39 ng/kg is Na as kindly demonstrated above. (molecular WT being 23 g/mol) How do I convert the Na measurement into cmol/L? 😅 thanks again Chris Link to comment Share on other sites More sharing options...
chenbeier Posted August 13, 2022 Share Posted August 13, 2022 (edited) As I wrote to make it accurate you need specific gravity of the solution. If you have this then you can convert ng/kg to ng/l Roughly 1 kg ~ 1 l The mass you can convert to mol with n = m/M In this case for 100 ppt it is 39 * 10^-9 g/ 23 g/ mol = 1,69 * 10^-9 mol This amount is in 1 l, so the concentration is 1,69*10^-9 mol/l. Edited August 13, 2022 by chenbeier Link to comment Share on other sites More sharing options...
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