AP Chemistry

Advanced Placement Chemistry exploring atomic structure, chemical bonding, and reactions.

Structure of the AtomElectron Configuration and Periodic TrendsTypes of Chemical Bonds
Molecular Geometry and VSEPR TheoryTypes of Chemical ReactionsStoichiometry and Chemical Calculations
Chemistry in MedicineEnvironmental ChemistryMaterials Science and Everyday Products
Mastering Multiple ChoiceSolving Free-Response Problems
Structure of the Ato...Electron Configurati...Types of Chemical Bo...Molecular Geometry a...Types of Chemical Re...Stoichiometry and Ch...Chemistry in Medicin...Environmental Chemis...Materials Science an...Mastering Multiple C...Solving Free-Respons...
Advanced Topics

Stoichiometry and Chemical Calculations

The Math of Chemistry

Stoichiometry is the calculation of reactants and products in chemical reactions, based on balanced equations.

  • Use mole ratios from coefficients in balanced equations.
  • Convert between grams, moles, and molecules.

Limiting Reactants and Yields

Often, one reactant runs out first (the limiting reactant), determining how much product forms. Calculating percent yield compares actual versus theoretical amounts.

Why It Matters

Stoichiometry is essential in industries like pharmaceuticals, where precise amounts are critical.

Key Formula

\[\text{moles} = \frac{\text{mass}}{\text{molar mass}}\]

Examples

  • Mixing 2 moles of hydrogen with 1 mole of oxygen produces 2 moles of water.

  • Determining the limiting reactant in a reaction between vinegar and baking soda.

In a Nutshell

Stoichiometry lets chemists calculate how much reactant is needed or product is formed.

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Chemistry in Medicine