Question

Given a balance chemical equation, 2 H2(g) O2(g) 2 H2O(g) If a reaction mixture contains 3 moles of O2(g) with 4 moles of H2(g), which reactant is the limiting reactant and what is the mass remaining of the reactant in excess

Answer 1

We have the equation $2\text{H}_{2}+\text{O}_{2} \longrightarrow 2\text{H}_{2}\text{O}$.

This means that for every mole of oxygen consumed, 2 moles of hydrogen are consumed.

• Considering the oxygen, the reaction can occur 3 times.
• Considering the hydrogen, the reaction can occur 4/2=2 times.

Therefore, hydrogen is the limiting reactant.

If all 4 moles of the hydrogen are consumed, then 2 moles of the oxygen will be consumed. This means 1 mole of oxygen, which has a mass of 15.9994 grams, will remain.