How many moles of oxygen gas would be needed to completely burn 8 moles of

hydrogen sulfide?

12 mol O2

Explanation:

This is assuming you're using a combustion equation of

2 H2S + 3O2 - > 2H2O + 2SO2

Next time include the equation because that is where you will find your mol to mol ratio

8 mol H2S x (3 mol O2 / 2 mol H2S) = 12 mol O2