Chapter 11

The Mole
The SI base unit used to measure the amount of a substance, abbreviated mol; one mole is the amount of a pure substance that contains 6.02x10^23 representative particles.
Avogadro's number
The number 6.0221367x10^23, which is the number of representative particles in a mole, and can be rounded to three significant digits: 6.02x10^23.
molar mass
The mass in grams of one mole of any pure substance.
percent composition
The percent by mass of each element in a compound.
empirical formula
A formula that shows the smallest whole-number ratio of the elements in a compound, and may or may not be the same as the actual molecular formula.
molecular formula
A formula that specifies the actual number of atoms of each element in one molecule or formula unit of the substance.
A compound has a specific number of water molecules bound to its atoms.