Lets say I have an ionic salt with a density of 1.3 g/mL that has a solubility of say, 10g/mL.

If I drop 1.3 grams of this salt into 1 mL of water and shake it until completely dissolved will the resulting solution have a volume of 2 mL? This would certainly be true for a completely insoluble compound (this is effectively how we measure the volume of insoluble solids); I'm wondering whether this holds true if the compound dissociates.

  • $\begingroup$ chemistry.stackexchange.com/questions/83765/… $\endgroup$ – Mithoron Aug 28 '18 at 17:50
  • $\begingroup$ @Mithoron No salt satisfying what properties? I pulled the density and solubility out of thin air. It sounds like the answer is yes then? The sum of the volumes of a soluble salt and solvent will not necessarily equal the volume of the solution. $\endgroup$ – David Reed Aug 29 '18 at 15:48
  • $\begingroup$ Even 1.3 g per mL would be really high solubility, 10 is rather impossible for salts. And of course there can and most probably would be volume contraction. It would be really weird if volume didn't change at all. $\endgroup$ – Mithoron Aug 29 '18 at 20:30
  • $\begingroup$ @Mithoron Ah gotcha. Yes it was just a hypothetical to setup the question. The 10mg was just to make sure it was clear that the salt completely dissolved (i.e. nonsaturated). The real question I was getting at was whether the sum of the volumes = the volume of the sum as is the case with insoluble compounds. $\endgroup$ – David Reed Aug 29 '18 at 20:50
  • $\begingroup$ @Mithoron, NH4NO3, at 20 °C, has a solubility of 192 g/100 ml, or 1.92 g/ml... and there are many more soluble salts, e.g. SbCl3 en.wikipedia.org/wiki/Solubility_table . And then there's thiotimoline: en.wikipedia.org/wiki/Thiotimoline $\endgroup$ – DrMoishe Pippik Aug 29 '18 at 23:25

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