Limiting Reagent Calculator Formula
Understand the math behind the limiting reagent calculator. Each variable explained with a worked example.
Formulas Used
Moles/Coefficient for A
ratio_a = moles_a / coeff_aMoles/Coefficient for B
ratio_b = moles_b / coeff_bVariables
| Variable | Description | Default |
|---|---|---|
moles_a | Moles of Reactant A(mol) | 2 |
coeff_a | Coefficient of A | 1 |
moles_b | Moles of Reactant B(mol) | 3 |
coeff_b | Coefficient of B | 2 |
How It Works
How to Find the Limiting Reagent
Method
Divide the moles of each reactant by its stoichiometric coefficient. The reactant with the smallest ratio is the limiting reagent.
Ratio = moles / coefficient
Worked Example
2 mol A and 3 mol B react with coefficients 1A + 2B.
moles_a = 2coeff_a = 1moles_b = 3coeff_b = 2
- 01Ratio A = 2 / 1 = 2
- 02Ratio B = 3 / 2 = 1.5
- 03B has the smaller ratio, so B is the limiting reagent
Ready to run the numbers?
Open Limiting Reagent Calculator