Why do the coefficients in a chemical equation determine how much of each substance reacts?
The coefficients express relative numbers of entities and therefore relative amounts of substance.
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The coefficients express relative numbers of entities and therefore relative amounts of substance.
Scene
See the scene
For a balanced reaction aA + bB → cC + dD, the coefficients a, b, c, and d define proportional changes in amount of substance.
The coefficients do not usually mean equal masses. Conversion between amount and mass requires molar mass.
Idea
Now name the idea
The quantitative relationships among reactants and products in a chemical reaction, based on the balanced chemical equation.
Why
Why it matters
Chemical equations describe relative numbers of microscopic entities. Amount of substance expresses those entity counts on a laboratory scale, so mole ratios preserve the equation's quantitative meaning.