Limiting Reactant Calculator
Find the limiting reactant, theoretical yield, and excess reactant in any reaction.
How to Find the Limiting Reactant
The limiting reactant is the "ingredient" that runs out first, stopping the reaction. To find it, you must run a "race" to see which reactant produces the least amount of product.
1. Balance the Equation
Ensure your chemical equation is balanced. The mole ratios are essential for correct calculations.
2. Convert to Moles
Convert the starting mass (in grams) of each reactant to moles using their respective molar masses.
3. Calculate Product Moles
For each reactant, calculate how many moles of product it could create using the mole ratio.
4. Identify the Limiting Reactant
The reactant that produces the smallest amount of product is the limiting reactant. This smallest amount is your theoretical yield.
Frequently Asked Questions
What is theoretical yield?
Theoretical yield is the maximum amount of product that can be produced from the given amounts of reactants, assuming the reaction goes to completion perfectly. It is determined by the limiting reactant.
What is the excess reactant?
The excess reactant is the reactant that is not completely used up when the reaction is finished. Some of it will be left over because the limiting reactant ran out first.
Why is finding the limiting reactant important?
In industrial chemistry and lab work, identifying the limiting reactant is crucial for predicting the maximum possible product yield, controlling costs by not wasting expensive reagents, and ensuring reaction efficiency.