This document discusses methods for determining the chemical composition of compounds including: 1) Counting atoms by converting between grams and moles using molar masses from the periodic table. 2) Calculating the mass of molecules from the masses of their constituent atoms. 3) Using molecular formulas as conversion factors between moles of atoms and molecules or grams of atoms and molecules.

1. Ch 06 Chemical Composition
6.1 How Much Sodium?
6.2 Counting Nails by the Pound
A. Not useful if we want to know how many nails we have
B. Need a conversion factor between mass and number of items
6.3 Counting Atoms by the Gram
A. Pair = 2; dozen = 12; mole = 6.02 x 1023
B. 1 mole of Au atoms = 6.02 x 1023 Au atoms
C. The periodic table gives the mass of 1 mole of that atom in grams
1. 1 mole of S atoms = 32.07 g S
2. 1 mole of C atoms = 12.01 g C
D. Unit conversions between grams and moles of atoms
6.4 Counting Molecules by the Gram
A. Mass of 1 mole H2O = mass of 2 moles of H + mass of 1 mole O
B. Calculations performed in a similar fashion
6.5 Chemical Formulas as Conversion Factors
A. Molecular formulas give ratios of atoms in molecule
B. Converting moles of atoms to moles of molecules
C. Converting grams of atoms to grams of molecules
6.6 Mass Percent Composition of Compounds
A. Percentage of molecule’s total mass that is due to element X
B. Convert between mass of element and mass of compound
6.7 Mass Percent Composition from a Chemical Formula
6.8 Calculating Empirical Formulas for Compounds
A. Empirical formula is the smallest whole number ratio of atoms
B. Can be different than molecular formula
C. Many different compounds may have the same empirical formula
6.9 Calculating Molecular Formulas for Compounds
A. Empirical formula molar mass
B. Compare molar mass to empirical formula mass