Aqueous strontium sulfide reacts with aqueous copper(II) nitrate to form aqueous strontium nitrate and a black precipitate of copper sulfide.
SrS (aq) + Cu(NO₃)₂ (aq) --> Sr(NO₃)₂ (aq) + CuS (s)
The chemical equation is balanced. Both the reactant and product side of the equation have one Sr²⁺ ion, one Cu²⁺ ion, one S²⁻ ion and one NO₃⁻ ion.