Question

A reaction mixture initially contains 4.8 mol ZnS and 9.5 mol O₂. Which is the limiting reactant?

A. ZnS
B. O₂
C. Both are limiting
D. Neither is limiting

Answer 1

To find the limiting reactant between ZnS and O₂, we compare the mole amounts to their stoichiometric coefficients in the balanced equation. With 4.8 mol ZnS and 9.5 mol O₂, ZnS can react 2.4 times and O₂ can react 3.17 times, so ZnS is the limiting reactant.

Step-by-step explanation:

To determine the limiting reactant in a chemical reaction, you need to compare the mole ratios of the reactants to their coefficients in the balanced chemical equation. In this case, we are dealing with a reaction between zinc sulfide (ZnS) and oxygen (O₂), which typically occurs according to the following balanced chemical equation:

2 ZnS + 3 O₂ → 2 ZnO + 2 SO₂

Now to find the limiting reactant, we must compare the amount of moles we have for each reactant to the stoichiometric coefficients in the balanced equation. Since the student has 4.8 mol ZnS and 9.5 mol O₂, we divide these amounts by their respective coefficients to see how many times each reactant can react completely:

• ZnS: 4.8 mol ÷ 2 = 2.4 times
• O₂: 9.5 mol ÷ 3 = 3.17 times

Since zinc sulfide can react fewer times than oxygen, ZnS is the limiting reactant.