Stoichiometry Calculator

Solve grams-to-grams problems with a step-by-step mole bridge visualizer.

Enter a balanced chemical equation:

Or, select a preset example:

Starting Mass (grams) Starting Substance

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Find Mass of

The Mole Bridge Method

Stoichiometry allows us to predict the amounts of reactants and products in a reaction. The "mole bridge" is the central concept, using the mole ratio from the balanced equation to convert from a known substance to an unknown one.

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1. Grams to Moles

Convert the mass of your starting substance into moles by dividing by its molar mass.

grams ÷ molar mass

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2. The Mole Bridge

Use the coefficients from the balanced equation to create a mole ratio, converting moles of your starting substance to moles of your target substance.

× (moles want / moles have)

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3. Moles to Grams

Convert the moles of your target substance back into grams by multiplying by its molar mass.

moles × molar mass