Key Concepts in Chemistry: Atoms, Moles, and Stoichiometry

atom

The smallest unit of an element.

formula unit

The smallest unit of an ionic compound.

molecule

The smallest unit of a molecular compound.

mole

A unit of measurement used to quantify the amount of a substance.

6.02 x 10^23

The number of particles in a mole.

molar mass

The mass of one mole.

Stoichiometry

Calculating quantities of reactants and products from a chemical equation.

limiting reactant

The reactant that gets used up first.

theoretical yield

The amount of product that should form during the reaction, determines the limiting reactant.

actual yield

The yield that differs from the theoretical yield.

empirical formula

The already reduced formula.

finding an empirical formula

Look for the option that cannot be reduced.

Limiting Reactant

The reactant that is completely consumed first.

Not Determined by Limiting Reactant

Actual yield of product formed in practice.