Ch 3: Empirical Formula + Hydrate Formula

1. The lowest mole ratio of the molecular structure
   1. Ex: Glucose
      1. CH2O

1. The exact molecular structure (# of moles) of a molecule
   1. Ex: Glucose
      1. C6H12O6

1. Percent Composition known
   1. EF
      1. If Molar mass is known, MF can be found.
2. Combustion Data
   1. React everything with oxygen to turn into oxides, called combustion
      1. Analyze using mole ratios to find EF
3. EF - Combustion Data
   1. Generally most compounds have carbon in them
   2. H, C, N
      1. When burned in air, reacting them with O2
         1. Carbon with Oxygen forms CO2, Carbon Dioxide
         2. Hydrogen with Oxygen forms H20, Water
         3. Nitrogen with Oxygen forms NO2
         4. Incomplete Combustion forms CO and CO2, not just CO2
      2. If mass of CO2 or H2O formed was known:
         1. Stoichiometry
            1. Moles of Carbon/Hydrogen/Nitrogen
               1. Divide them by smallest number of moles
                  1. Must be a whole #, if a fraction turn into a whole #
                     1. Round only if >0.9 or <0.1
         2. Mole Ratios
            1. Moles of CO2/H2O/NO2 using Molar Mass
   3. For extra O, Mass of O is Total Mass - (mass of C + mass of H)

Attachments:

• Ch 2: Naming

1. To find the prefix of a hydrate:
   1. Heat the compound to drive off the water, and having measured the two masses, the mass of the hydrate can be found by subtracting the mass of the anhydrous solution from the original hydrate solution
      1. Divide mass of hydrate with molar mass of water
         1. Results in moles of water
      2. Divide mass of anhydrous compound by molar mass of anhydrous compound
         1. Results in moles of anhydrous compound
            1. Use both to find hydrate