Sciencemadness Discussion Board

NH4Cl & CaSO4 from (NH4)2SO4 + CaCl2?

RogueRose - 20-3-2017 at 04:13

Some Ammonium sulfate & calcium chloride got mixed when I was crystallizing the sulfate and the CaCl2 was acting as a desiccant in a container. The lid got open somehow and the CaCl2 absorbed so much moisture it contaminated the sulfate mixing the two. It basically stayed a clear liquid so I wasn't sure if anything was happening. I

After boiling to evaporate the two a fine white precipitate evolved and seems very similar to CaSO4 in feeling/texture. I'm guessing that is what happened but is it normal that it would need heat for the reaction to work?

Would KCl and (NH4)2SO4 react to produce K2SO4 and NH4Cl? Would heat be needed for this as well?

Gustavo_Marzullo - 20-3-2017 at 04:19

Both of the products are soluble in water, so it won't happen a double displaciment reaction. You'll get a misture of KCl, (NH4)2SO4, K2SO4 and NH4Cl.

Melgar - 20-3-2017 at 07:52

OP is using calcium chloride, no potassium ions in that.

As for the actual salts used, ammonia/ammonium tends to increase water's solvation ability for metal ions, and can coordinate with calcium ions to stabilize the double salt, ammonium calcium sulfate. Heat would tend to break up these coordination complexes.

If the quantities mixed had been stochiometric though, ammonium chloride and calcium sulfate would have completely displaced the original salts.