Final answer:
To balance the chemical equation H2 + Cl2 → HCl, a coefficient of 2 is placed in front of HCl to match the number of atoms on both sides, resulting in the balanced equation H2(g) + Cl2(g) → 2HCl(g). This reflects a stoichiometric ratio of 1:1 between hydrogen and chlorine and allows understanding of limiting and excess reactants in stoichiometric calculations.
Step-by-step explanation:
To balance the chemical equation H₂ + Cl₂ → HCl, we need to ensure that there are equal numbers of each type of atom on both sides of the equation. Initially, there are two hydrogen atoms and two chlorine atoms in the reactants and one hydrogen atom and one chlorine atom in the product. By placing a coefficient of 2 in front of HCl, the balanced equation becomes:
H₂(g) + Cl₂(g) → 2HCl(g)
With this balance, there are now two hydrogen atoms and two chlorine atoms on both sides of the equation. This balancing act reflects the stoichiometric ratio of 1:1 for hydrogen to chlorine.
Understanding the concept of limiting and excess reactants is critical in stoichiometry. If reactants are provided in any ratio other than the stoichiometric ratio, one reactant will be fully consumed (limiting reactant), while the other will be in excess. For instance, if 3 moles of H₂ are combined with 2 moles of Cl₂, Cl₂ would be the limiting reactant since it is less than the required stoichiometric ratio compared to H₂. As a result, some amount of H₂ would remain unreacted.
The balanced chemical equation for the reaction between hydrogen and chlorine to form hydrogen chloride is:
H₂ + Cl₂ → 2HCl
This equation is balanced because there are two hydrogen atoms and two chlorine atoms on both sides of the equation. The coefficients in front of the formulas indicate the number of molecules or moles involved in the reaction.