Answer
Complete ionic equation:
$Mg^{2+}(aq) + S^{2-}(aq) + Cu^{2+}(aq) + 2Cl^-(aq) --\gt CuS(s) + Mg^{2+}(aq) + 2Cl^-(aq)$
Net ionic equation:
$Cu^{2+}(aq) + S^{2-}(aq) -- \gt CuS(s) $
Work Step by Step
1. Balance the equation:
$MgS(aq) + CuCl_2(aq) -- \gt CuS(s) + MgCl_2(aq)$
It is already balanced.
2. For the strong electrolytes in aqueous state, separate the ions:
$MgS, CuCl_2$ and $MgCl_2$: Strong electrolytes. (Completely dissociated in water).
$Mg^{2+}(aq) + S^{2-}(aq) + Cu^{2+}(aq) + 2Cl^-(aq) --\gt CuS(s) + Mg^{2+}(aq) + 2Cl^-(aq)$
- This is the balanced complete ionic equation.
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3. Remove the spectator ions:
- Remove the ions that appear unchanged after the reaction.
$Mg^{2+}$ and $2Cl^-$ don't react.
$Cu^{2+}(aq) + S^{2-}(aq) -- \gt CuS(s) $
- This is the balanced net ionic equation.