Final answer:
To determine the moles of excess NaOH remaining after the reaction with CO₂, use the stoichiometry of the balanced chemical equation, subtracting twice the moles of reacted CO₂ from the initial moles of NaOH.
Step-by-step explanation:
To find out how many moles of the excess reactant remain after the completion of the reaction, where sodium hydroxide reacts with carbon dioxide, we start with the balanced chemical equation: 2NaOH(s) + CO₂(g) → Na₂CO₃(s) + H₂O(l). This equation tells us that 2 moles of NaOH react with 1 mole of CO₂ to produce 1 mole of Na₂CO₃ and 1 mole of H₂O.
Suppose we have more NaOH than needed to completely react with CO₂. After the reaction is complete, assuming CO₂ is the limiting reactant, we can calculate the remaining amount of NaOH using stoichiometry. If the initial moles of NaOH and CO₂ are known, we subtract the consumed moles of NaOH (twice the moles of CO₂ reacted) from the initial moles to find the moles of excess NaOH.