Calculator
Example Data Table
| Reaction | Reactant | Coefficient | Available moles | Product coefficient | Yield | Expected result |
|---|---|---|---|---|---|---|
| N₂ + 3H₂ → 2NH₃ | N₂ | 1 | 2.00 | 2 | 85% | H₂ limits product |
| N₂ + 3H₂ → 2NH₃ | H₂ | 3 | 5.00 | 2 | 85% | 2.833 mol NH₃ actual |
Formula Used
Moles from mass: moles = mass ÷ molar mass
Pure reactant moles: pure moles = entered moles × purity ÷ 100
Product moles from one reactant: product moles = pure reactant moles × product coefficient ÷ reactant coefficient
Limiting product moles: theoretical product moles = smallest product mole estimate
Actual product moles: actual product moles = theoretical product moles × percent yield ÷ 100
Product mass: product mass = actual product moles × product molar mass
How to Use This Calculator
- Balance the chemical equation first.
- Enter the product name and its balanced coefficient.
- Enter product molar mass if you also want grams.
- Enter each reactant coefficient from the balanced equation.
- Enter direct moles, or enter mass and molar mass.
- Add purity for each reactant sample.
- Enter percent yield for the expected reaction performance.
- Press calculate and read the limiting reagent result.
Stoichiometry Product Mole Planning
Core Idea
Stoichiometry links a balanced chemical equation to measurable laboratory amounts. This calculator focuses on product moles. It accepts reactant coefficients, available moles, masses, molar masses, purity, and percent yield. It then compares each usable reactant. The smallest product amount becomes the limiting prediction. That makes the result useful for homework, lab notebooks, and quick process checks.
Why Product Moles Matter
Product moles show how much material a reaction can form before conversion to grams, liters, or particles. The mole ratio comes from equation coefficients. For example, one mole of nitrogen reacts with three moles of hydrogen to form two moles of ammonia. If hydrogen is short, hydrogen controls the possible ammonia. Extra nitrogen stays unreacted.
Advanced Inputs
Real samples are rarely perfect. A reagent may be only ninety eight percent pure. A reaction may also give less product than theory predicts. This page adjusts for both issues. Direct mole entries are used first. If direct moles are blank, the calculator uses mass divided by molar mass. Purity changes gross moles into effective moles. Yield changes theoretical product into actual expected product.
Limiting Reagent Logic
Each reactant produces its own product estimate. The estimate equals available pure moles multiplied by the product coefficient, then divided by the reactant coefficient. The lowest estimate is selected. That reactant is named as limiting. Other reactants are marked as excess. The page also reports how many moles of each reactant would be required at the limiting product level.
Careful Use
Always balance the equation before entering coefficients. Use consistent units for molar mass. Molar mass should be in grams per mole when mass is in grams. Use zero or blank fields for unavailable reactant rows. Review the step notes before copying the final value. Rounding is shown, but your teacher or lab may require specific significant figures.
Good Practice
A stoichiometry answer is strongest when it includes the balanced equation, limiting reagent, theoretical moles, actual moles, and assumptions. Keep purity and yield separate. Do not hide them inside coefficients. This makes the work easier to audit and correct. Students can compare scenarios by changing only one row. This supports planning before expensive chemicals are weighed or mixed in practical classroom experiments.
FAQs
What does this calculator find?
It finds theoretical and actual moles of a product. It uses balanced equation coefficients, reactant amounts, purity, and percent yield.
Do I need a balanced equation?
Yes. Stoichiometry depends on mole ratios from a balanced equation. Wrong coefficients will give wrong product moles.
Can I enter grams instead of moles?
Yes. Enter mass and molar mass for a reactant. The calculator converts them into moles before applying mole ratios.
What happens if I enter direct moles and mass?
Direct moles are used first. Mass and molar mass are used only when direct moles are left blank.
How is the limiting reactant selected?
Each reactant gives a possible product mole amount. The smallest product amount identifies the limiting reactant.
What does purity percent mean?
Purity adjusts the available reactant. A 90 percent pure sample contributes only 90 percent of its calculated gross moles.
What does percent yield change?
Percent yield changes theoretical product moles into expected actual moles. It accounts for incomplete reaction and product loss.
Can this calculator show product mass?
Yes. Enter the product molar mass. The calculator multiplies actual product moles by molar mass to estimate grams.