1. Chapter 7 Sec. 1 Avagadro’s # and Molar Calc.
Sec. 2 Relative atomic mass & Chemical Formulas
Sec. 3 Formulas and percent composition

2. Avagadro’s # and Molar Conversions
Identify the mole as the unit used to count particles.
Use Avagadro’s # to convert between moles and particles
Solve problems converting between mass, moles, and particles.

3. Avagadro’s number
Avagardo’s # is the number of particles in one mole of substance. This number does not change.
6.022 X 1023 (atoms, ions, molecules)/mol

4. Sec. 2 Relative atomic mass and Chemical Formulas
Use a periodic table to determine the average atomic mass of elements
Infer information about a compound from its chemical formula.
Determine the molar mass of a compound from its chemical formula

5. Relative atomic mass
The atomic mass on the periodic table is an average of all isotopes of that compound found in nature.
If the percentages of each isotope are known, we can then calculate the average atomic mass.
Turn to page 235

6. Chemical Formulas
Covalent cmpd’s formulas represent all atoms present in one molecule of the cmpd.
Ionic cmpd’s formulas represent the simpliest ratio of atoms in the cmpd.
Calculating molar mass of cmpd’s on page 239.

7. Sec. 3 Formulas and % Composition
Determine a cmpd’s empirical formula from its percent composition
Determine the molecular formula of a compound from its empirical formula and its formula mass.
Calculate percent composition of a compound from its molecular formula or formula unit.

8. Section # Formulas
Empirical Formula is the reduced formula of a molecule.
Molecular Formula is the actual number of atoms in each molecule