Stoichiometric Calculator

Molecular and ionic equation balancing, limiting reagent and theoretical yield

Chemical equation

Tip: Use plain numbers for subscripts (H2O) and + or - signs at the end for ions (Fe+3, SO4-2)

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\text{H}_{2} + \text{O}_{2} \rightarrow \text{H}_{2}\text{O}

Elements in equation

Explore Elements1 / 118

Nonmetal

Hydrogen

1.008 u

Results

Balanced equation

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Stoichiometric coefficients

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Molar masses

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Reactant Masses

Enter masses to calculate the limiting reagent

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Limiting reagent—

Excess reagents

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Theoretical yield

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Fundamentals & Explanation

Law of Conservation of Mass

\sum m_{\text{reactants}} = \sum m_{\text{products}}

Limiting Reagent

\text{LR} = \min\left(\frac{n_i}{a_i}\right)

Where n_i is the available moles and a_i is the stoichiometric coefficient.

Redox Balancing

\sum \text{e}^{-}_{\text{lost}} = \sum \text{e}^{-}_{\text{gained}}

1. Law of Conservation of Mass (Lavoisier)

In every chemical reaction, the total mass of reactants equals the total mass of products. Atoms are neither created nor destroyed — they are simply rearranged. Stoichiometric balancing ensures each element has the same number of atoms on both sides of the equation.

2. Limiting Reagent

When defined amounts of reactants are mixed, the limiting reagent is the one that is completely consumed first, determining the maximum amount of product that can be formed. The remaining reactants are said to be in excess.

3. Charge Balancing in Redox Reactions

In oxidation-reduction reactions, besides conserving mass, the electric charge must also be conserved. The electrons lost by the oxidized species must equal the electrons gained by the reduced species.

Theoretical yield: the maximum amount of product calculated from the limiting reagent, assuming a complete reaction (100% yield).

IUPAC — Nomenclature
Reference: R. Chang, Chemistry, 13th ed., McGraw-Hill, 2019.

Stoichiometric Calculator

Results

Fundamentals & Explanation

1. Law of Conservation of Mass (Lavoisier)

2. Limiting Reagent

3. Charge Balancing in Redox Reactions

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1. Law of Conservation of Mass (Lavoisier)

2. Limiting Reagent

3. Charge Balancing in Redox Reactions