Question 1

What is a limiting reagent?

Accepted Answer

The limiting reagent is the reactant that is completely consumed first in a reaction, determining the maximum amount of product that can form. The other reactant(s) are in excess.

Question 2

How do I find the limiting reagent?

Accepted Answer

Divide the moles of each reactant by its stoichiometric coefficient. The reactant with the smallest ratio is the limiting reagent.

Question 3

What happens to the excess reagent?

Accepted Answer

The excess reagent is not completely consumed. Some of it remains unreacted after all the limiting reagent is used up. The amount remaining equals the initial amount minus what was consumed.

Question 4

Why is identifying the limiting reagent important?

Accepted Answer

The limiting reagent determines the theoretical yield (maximum product possible). Using the wrong reactant to calculate yield will give an incorrect answer. In industry, limiting reagents affect cost and waste.

Limiting Reagent Calculator

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