Dear Sumeia,

% w/v

Mass percent solutions are defined based on the grams of solute per 100 mL of solution.

Therefore, for preparing 55% ammonium carbonate solution, you need to dissolve 55 gram ammonium carbonate.H2O in a sufficient amount of water and add water to obtain a final volume of 100 mL.

The preparation of 40% will be similar to that of 55%, however, the quantity of ammonium carbonate will be 40 g .

I should indicate that the solubility of ammonium carbonate.H2O in water at 0 C is 55.8 g per 100 mL water. Therefore, I suggest to prepare 55 % solution. The preparation should be at low temperature and avoid any warming or heat. Please note that you can not prepare 80% solution since the maximum solubility of ammonium carbonate.H2O in water is 55.8 g/100 mL.

For more see the Table contained in the following link:

https://en.wikipedia.org/wiki/Solubility_table

Please note that ammonium carbonate slowly decomposes at standard temperature and pressure through two pathways. Thus any initially "pure" sample of ammonium carbonate will soon become a mixture including various byproducts.

Ammonium carbonate can spontaneously decompose[clarification needed] into ammonium bicarbonate and ammonia:

(NH4)2CO3 → NH4HCO3 + NH3

It is suggested not to heat the ammonium carbonate solution and to store it in a cool place (0 C).

Hoping this will be helpful,

Rafik

Thank you very much, it was so helpful.

Thanks Prof. Rafik Karaman for interesting answer,

I need to make supersaturated ammonium carbonate solution. Do I follow the same procedures?

Thanks