[Catround]

Hello everyone,

I made two solutions in water of copper salts, CuSO4 and CuCl2. I added ammonia solution (5M) warming the solutions at about 100°C. At the beginning a blue precipitate was formed in each solution (Cu(OH)2). Adding other ammonia solution in the CuSO4 solution a deep blue clolour appeared ( [Cu(NH3)4]2+ I guess no?) and the precipitate disappeared. IN the other solution keep adding ammonia, a black precipitate appeared; I think this one is the copper oxyde (CuO) but my question is: why it was formed only from the solution of CuCl2 and it did'nt form from the solution of CuSO4?

Another question. I added K4[Fe(CN)6] to a water solution of CuSO4. A red precipitate was formed. What is it?

Thanks.