gen-briefly-explain-stoichiometry-and-one-common-misconception-a-b028

Briefly explain stoichiometry and one common misconception about it.

# Stoichiometry **Stoichiometry** is the quantitative study of reactants and products in chemical reactions. It uses balanced chemical equations to calculate the amounts of substances consumed and produced, based on the fixed ratio in which atoms and molecules combine. For example, in the reaction 2H₂ + O₂ → 2H₂O, the coefficients tell us that 2 molecules (or moles) of hydrogen react with 1 molecule (or mole) of oxygen to produce 2 molecules (or moles) of water. ## Common Misconception **Coefficients represent masses**: Many students mistakenly think the coefficients in a balanced equation directly represent mass ratios. In reality, coefficients represent **mole ratios** (or molecule ratios). While you can convert these to masses using molar mass, 2H₂ + O₂ → 2H₂O doesn't mean "2 grams of hydrogen + 1 gram of oxygen = 2 grams of water." It means 2 *moles* of H₂ react with 1 *mole* of O₂. When converted to mass, this is actually 4 g + 32 g → 36 g, which obeys conservation of mass but shows the coefficients aren't direct mass values.