[powell]

Hello, as a part of my senior chemistry course we did a lab that included the following:

1.)pour CuSO4 into a test tube (1 cm depth) (light blue in colour).
2.) Add NH3 solution with drops until the colour is just blue.

When doing #2 the solution turned a dark blue colour on top, a precipitate was formed in the middle, and the remaining substance was a lighter blue on the bottom.

so so far we have:

CuSO4 (aq) + 4NH3 (aq) -----> ?

The teacher has mentioned that the precipitate is formed through a 2 step reaction.

If you shake the test tube the precipitate will disappear.

You can repeat the procedure in the same test tube.

The teacher has asked us to find out what the 2 step reactions will be.

Any help is greatly appreciated, thanks.
Any help i

[AWK]

The precipitate is formed in the first step
Cu²⁺ + 2OH^- = Cu(OH)₂(s)
then
Cu(OH)₂(s) + 4NH₃ = [Cu(NH₃)₄]²⁺ + 2OH^-

[powell]

Thank you very much, i also have a followup question:

Cu(NH3) + H2SO4 -----> ?

I think that this reaction will yield:


Cu(NH3) + 2 H2SO4 ------> Cu(SO4) + 2(H2O) + S02 + NH3

but am not too certain,

thanks again

[Borek]

Cu(NH3) + H2SO4 -----> ?

You have missed charges and numbers in formulas, so it hard to tell that the question asks about. Check them.

[AWK]

But in any way NH3 reacts with H2SO4 to form (NH4)2SO4