Stoichiometry: Rapid Review for AP Chemistry

By — McGraw-Hill Professional
Updated on Feb 1, 2011

For a more thorough review, refer to these concepts:

Rapid Review

  • The mole is the amount of substance that contains the same number of particles as exactly 12 g of carbon-12.
  • Avogadro's number is the number of particles per mole, 6.022 × 1023 particles.
  • A mole is also the formula (atomic, molecular) mass expressed in grams.
  • If you have any one of the three—moles, grams, or particles—you can calculate the others.
  • The empirical formula indicates which elements are present and the lowest whole-number ratio.
  • The molecular formula tells which elements are present and the actual number of each.
  • Be able to calculate the empirical formula from percent composition data or quantities from chemical analysis.
  • Stoichiometry is the calculation of the amount of one substance in a chemical equation by using another one.
  • Always use the balanced chemical equation in reaction stoichiometry problems.
  • Be able to convert from moles of one substance to moles of another, using the stoichiometric ratio derived from the balanced chemical equation.
  • In working problems that involve a quantity other than moles, sooner or later it will be necessary to convert to moles.
  • The limiting reactant is the reactant that is used up first.
  • Be able to calculate the limiting reactant by the use of the mol/coefficient ratio.
  • Percent yield is the actual yield (how much was actually formed in the reaction) divided by the theoretical yield (the maximum possible amount of product formed) times 100%.
  • A solution is a homogeneous mixture composed of a solute (species present in smaller amount) and a solvent (species present in larger amount).
  • Molarity is the number of moles of solute per liter of solution.
  • Be able to work reaction stoichiometry problems using molarity.
  • Always use the balanced chemical equation in reaction stoichiometry problems.
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