Iron(II) sulfide reacts with hydrochloric acid according to the reaction: FeS(s) + 2 HCl(aq) → FeCl₂(s) + H₂S(g) A reaction mixture initially contains 0.223 mol FeS and 0.652 mol HCl. Once the reaction has occurred as completely as possible, what amount (in moles) of the excess reactant remains?

Verified step by step guidance

1. Identify the balanced chemical equation: FeS(s) + 2 HCl(aq) → FeCl_2(s) + H_2S(g).
2. Determine the stoichiometry of the reaction: 1 mole of FeS reacts with 2 moles of HCl.
3. Calculate the moles of HCl required to completely react with 0.223 mol of FeS using the stoichiometry from the balanced equation.
4. Compare the moles of HCl required with the moles of HCl available (0.652 mol) to determine the limiting reactant.
5. Subtract the moles of HCl that reacted from the initial moles of HCl to find the moles of excess HCl remaining.

Key Concepts

Stoichiometry

Stoichiometry is the calculation of reactants and products in chemical reactions based on the balanced chemical equation. It allows us to determine the proportions of substances consumed and produced, which is essential for identifying limiting and excess reactants in a reaction.

Limiting Reactant

The limiting reactant is the substance that is completely consumed first in a chemical reaction, thus determining the maximum amount of product that can be formed. Identifying the limiting reactant is crucial for calculating how much of the excess reactant remains after the reaction has occurred.

Excess Reactant

The excess reactant is the substance that remains after the reaction has gone to completion. By calculating the amount of the limiting reactant used, we can determine how much of the excess reactant is left over, which is important for understanding the efficiency of the reaction.