Limiting Reactants

Limiting Reactant

The reactant that is completely consumed first in a chemical reaction, determining the maximum amount of product that can be formed.

Effect of the Limiting Reactant

Once the limiting reactant is completely used up, the reaction stops even if other reactants are still available.

Excess Reactant

The reactant that remains after the limiting reactant has been completely consumed.

Application of Limiting Reactant

Used to determine which reactant limits the amount of product formed in a chemical reaction.

Step 1 of Identify the Limiting Reactant: Write the Balanced Equation

Ensure the chemical equation is balanced before performing calculations.

Step 2 of Identify the Limiting Reactant: Find the Stoichiometric Mole Ratio

Determine the mole ratio of the reactants from the coefficients in the balanced equation.

• The whole numbers in the reactants will be used in division.

Step 3 of Identify the Limiting Reactant: Find the Molar Masses

Determine the molar mass of each reactant.

• use the periodic table

Step 4 of Identify the Limiting Reactant: Convert Grams to Moles

Divide the given mass by the molar mass of each reactant.

• divide the given grams with the actual molar grams that can be seen in the periodic table

Step 5 of Identify the Limiting Reactant: Find the Actual Mole Ratio

Divide the moles of the chosen first reactant by the moles of the second reactant.

• divide the answers of both reactants that can be seen in the step 4 with each other.

Step 6 of Identify the Limiting Reactant: Compare the Actual and Stoichiometric Ratios

Compare the calculated actual ratio with the stoichiometric ratio.

If Actual Ratio > Stoichiometric Ratio

The first reactant is the excess reactant.

If Actual Ratio < Stoichiometric Ratio

The first reactant is the limiting reactant.