Stoichiometry: counting with an equation
A balanced chemical equation gives ratios between amounts of substance. Coefficients represent proportions of molecules or moles, not direct mass ratios.
Core idea
A balanced chemical equation gives ratios between amounts of substance. Coefficients represent proportions of molecules or moles, not direct mass ratios.
A concrete example
In 2 H₂ + O₂ → 2 H₂O, two moles of hydrogen react with one mole of oxygen. Molar masses are then needed to convert those amounts into grams.
Why it matters
This concept connects symbolic scientific language with what actually happens at atomic, molecular or experimental scales. Before applying a formula, always check the quantities, units and assumptions of the model.
Check it yourself
Restate the idea without technical vocabulary, then repeat the reasoning with a simple value. If your explanation and calculation tell different stories, revisit the assumptions.
In 2 H₂ + O₂ → 2 H₂O, two moles of hydrogen react with one mole of oxygen. Molar masses are then needed to convert those amounts into grams.