How many moles of O2 are required
if 12 moles of CuFeS are consumed?

24 moles of oxygen are required.

Explanation:

Given data:

Number of moles of CuFeS = 12 mol

Number of moles of O₂ react = ?

Solution:

Chemical equation:

2CuFeS + 4O₂       →       Cu₂S + 3SO₂ + 2FeO

now we will compare the moles of O₂ and CuFeS.

                         CuFeS       :        O₂

                              2            :         4

                             12            :         4/2×12 = 24 mol