Dear Azita... A very good relation exists between the density of ammonia water solution and its concentration. At 0% the density is that of water. As concentration increases the density decrease. The are many table in several publications to cover this relation. Good luck.

1500ppm indicates that1500 mg of ammonia in one litre of solution or 1.5 g of ammonia in one litre of solution. If we convert it in moles, then divide it by molecular weight of ammonia which comes to 0.088 moles. It can be converted into ml as ammonia is in liquid by dividing mass by density.

Hello Azita - we published an open access paper recently where we had to make these kinds of calculations. Please see the footnote with formulas in Table 1 where the pKa is a function of temperature:

Article Efficacy of NH3 as a secondary barrier treatment for inactiv...

Here is another good resource:

Article Aqueous Ammonia Equilibrium Calculations: Effect of pH and Temperature

Good luck with your research,

Jacek