Final answer:
The limiting reagent is the substance in a chemical reaction that is used up first, determining the maximum amount of product that can be produced. Mass-mass calculations are used to identify the limiting reagent and to predict the amount of product and excess reactants.
Step-by-step explanation:
Understanding Limiting Reagents in Chemical Reactions
What is true about limiting reagents? The limiting reagent is the reactant in a chemical reaction that is completely consumed first, limiting the amount of product that can be formed. Once the limiting reagent is used up, the reaction stops, and no more product can be produced, even if other reactants are still present in excess.
To identify a limiting reagent, one must perform mass-mass calculations or mole-mass calculations. These calculations compare the amount of product that can be formed from each reactant based on stoichiometry. The reactant that produces the least amount of product is the limiting reagent. This approach is essential to predict how much product will be generated and how much of the other reactants will remain unreacted when the reaction has run its course.
The limiting reagent concept is not only crucial in theoretical chemistry but also in practical applications, such as manufacturing processes, where knowing the exact amounts of substances needed can save costs and prevent excess waste.