Final answer:
To find the amount of a required substance using the limiting reagent, balance the equation, convert mass to moles, determine the moles of product via stoichiometry, and then convert back to mass if needed. Use mole-mass or mass-mass calculations to identify which reactant is limiting.
Step-by-step explanation:
To use the amount of limiting reagent to find the amount of required substance, you need to follow a sequence of steps which involve stoichiometric calculations. First, you must recognize the limiting reactant by conducting a mole-mass or mass-mass calculation which compares the expected product yield from each reactant. The reactant that produces the least amount of product is the limiting reagent. To find the amount of product formed from the limiting reagent:
- Balance the chemical equation to understand the mole ratio of reactants to products.
- Convert the mass of reactants to moles using the molar mass of each reactant.
- Apply the stoichiometry of the balanced equation to determine the moles of product that can be formed from the limiting reagent.
- Convert the moles of product back to mass if required.
If a reactant is in excess, you can calculate the remaining amount by subtracting the mass of the reactant that reacted with the limiting reagent from the original mass provided. This will tell you how much of the excess reagent is left after the reaction.