⚗️ Stoichiometry Calculator
Calculate product quantities from reactant masses using balanced chemical equations and mole ratios.
Molar mass: 2.016 g/mol
Molar mass: 18.015 g/mol
From balanced equation
From balanced equation
Product Mass
17.872 g
Reactant
- Mass: 2.0 g
- Moles: 0.992063 mol
- Coefficient: 2
Product
- Mass: 17.872 g
- Moles: 0.992063 mol
- Coefficient: 2
How to Use This Calculator
Enter chemical formulas
Input the reactant and product formulas using standard chemical notation (e.g., H2, H2O, C6H12O6). The calculator automatically calculates molar masses.
Provide reactant mass
Enter the mass of the reactant in grams. This is the starting quantity you have available.
Set stoichiometric coefficients
Enter the coefficients from your balanced chemical equation. For example, in 2H2 + O2 → 2H2O, the coefficients are 2, 1, and 2 respectively.
Review results
The calculator shows the product mass, moles of reactant and product, and all intermediate calculations based on the mole ratio.
Formula
n_reactant = m_reactant / M_reactant
n_product = (n_reactant / coeff_reactant) × coeff_product
m_product = n_product × M_product
Where n is moles, m is mass (g), M is molar mass (g/mol), and coeff is the stoichiometric coefficient from the balanced equation.
Example
For 2H2 + O2 → 2H2O with 2.0 g H2: n_H2 = 2.0 / 2.016 = 0.992 mol. Using coefficients 2:2, n_H2O = 0.992 mol. m_H2O = 0.992 × 18.015 = 17.9 g.
Full Description
Stoichiometry is the calculation of quantities in chemical reactions based on balanced chemical equations. This calculator automates the process of converting reactant masses to product masses using mole ratios from balanced equations.
The tool accepts any valid chemical formula and automatically calculates molar masses using a comprehensive periodic table database. You provide the reactant mass and the stoichiometric coefficients from your balanced equation, and the calculator handles all conversions between mass and moles.
Ideal for
- Laboratory work: Calculate how much product to expect from a given amount of reactant.
- Educational use: Practice stoichiometry problems and verify homework solutions.
- Reaction planning: Determine reagent quantities needed for synthesis reactions.
- Yield calculations: Compare theoretical yields with actual experimental results.
Key Features
- ✅ Automatic molar mass calculation from chemical formulas
- ✅ Supports complex formulas with parentheses and hydrates
- ✅ Handles stoichiometric coefficients from balanced equations
- ✅ Shows intermediate calculations (moles) for transparency
- ✅ Real-time updates as you modify inputs
Frequently Asked Questions
How do I balance a chemical equation?
Balancing equations requires ensuring equal numbers of each element on both sides. Use trial and error or systematic methods. The calculator assumes you've already balanced the equation and provides the coefficients.
What if my equation has multiple reactants or products?
This calculator handles one reactant and one product at a time. For complex reactions, calculate each product separately or use the limiting reactant concept to determine which reactant controls the reaction.
Can I use this for limiting reactant problems?
Yes. Calculate the product mass from each reactant separately, then the limiting reactant produces the smallest amount of product.
What if my formula has parentheses or hydrates?
The calculator supports complex formulas including parentheses (e.g., Ca(NO3)2), brackets, and hydrates (e.g., CuSO4·5H2O). Enter them using standard chemical notation.
How accurate are the molar mass calculations?
Molar masses use standard atomic weights from the periodic table with precision suitable for most calculations. For isotopic work, you may need to adjust atomic masses manually.
Can I calculate percent yield?
This calculator provides theoretical yield. To find percent yield, divide actual yield by theoretical yield and multiply by 100: % yield = (actual / theoretical) × 100.