Justify that the reaction:
$2 Cu_{2}O_{(s)} + Cu_{2}S_{(s)} \rightarrow 6 Cu_{(s)} + SO_{2(g)}$
is a redox reaction. Identify the species oxidised/reduced,which acts as an oxidant and which acts as a reductant.

(N/A) Assigning oxidation numbers to each species:
$2 \overset{+1}{Cu}_{2} \overset{-2}{O}_{(s)} + \overset{+1}{Cu}_{2} \overset{-2}{S}_{(s)}$ $\rightarrow 6 \overset{0}{Cu}_{(s)} + \overset{+4}{S} \overset{-2}{O}_{2(g)}$
In this reaction,the oxidation state of $Cu$ decreases from $+1$ to $0$ (reduction),and the oxidation state of $S$ increases from $-2$ to $+4$ (oxidation).
Since both oxidation and reduction occur simultaneously,it is a redox reaction.
Species reduced: $Cu$ (in $Cu_{2}O$ and $Cu_{2}S$).
Species oxidised: $S$ (in $Cu_{2}S$).
Oxidant (Oxidizing agent): $Cu_{2}O$ (as it provides $Cu$ to be reduced).
Reductant (Reducing agent): $Cu_{2}S$ (as it provides $S$ to be oxidised).