Question

 Aqueous solutions of sodium sulfide, Na2S, and copper nitrate, Cu(NO3)2, are mixed.  A precipitate of copper sulfide, CuS, forms at once.  Left behind is a solution of sodium nitrate, NaNO3.   Write the net ionic equation for this reaction.

Answer 1

$Na_2S_{(aq)}+Cu(NO_3)_{2(aq)}\to\>CuS_{(s)}+2NaNO_{3(aq)}$

$S^{2-}+Cu^{2+}_{(aq)}\to\>CuS_{(s)}$