Question

there are two steps in the extraction of copper metal from chalcocite, a copper ore. in the first step, copper(ⅰ) sulfide and oxygen react to form copper(ⅰ) oxide and sulfur dioxide: 2cu₂s(s)+3o₂(g)→2cu₂o(s)+2so₂(g). in the second step, copper(ⅰ) oxide and carbon react to form copper and carbon monoxide: cu₂o(s)+c(s)→2cu(s)+co(g). write the net chemical equation for the production of copper from copper(ⅰ) sulfide, oxygen and carbon. be sure your equation is balanced.

Explanation:

Step1: Multiply equations if needed

The first - step reaction is $2Cu_2S(s)+3O_2(g)
ightarrow2Cu_2O(s) + 2SO_2(g)$. The second - step reaction is $Cu_2O(s)+C(s)
ightarrow2Cu(s)+CO(g)$. To cancel out $Cu_2O$, we don't need to multiply the equations since the coefficient of $Cu_2O$ is 2 in the first reaction and 1 in the second reaction.

Step2: Add the two reactions

Add the two chemical equations together. The $2Cu_2O(s)$ on the product side of the first equation and the $Cu_2O(s)$ on the reactant side of the second equation will cancel out (after multiplying the second equation by 2 to balance the $Cu_2O$).
Multiply the second equation by 2: $2Cu_2O(s)+2C(s)
ightarrow4Cu(s)+2CO(g)$.
Now add the first equation $2Cu_2S(s)+3O_2(g)
ightarrow2Cu_2O(s) + 2SO_2(g)$ and the multiplied - second equation:
$2Cu_2S(s)+3O_2(g)+2C(s)
ightarrow4Cu(s)+2SO_2(g)+2CO(g)$

Answer:

$2Cu_2S(s)+3O_2(g)+2C(s)
ightarrow4Cu(s)+2SO_2(g)+2CO(g)$