Download Unit 03 Chapter 3 Notes

AP Chemistry
Unit 3
Chapter 3
I. Atomic Masses
A. Carbon 12 standard
B. Mass Spectrometer
1. Most accurate method for comparing the masses of atoms
2.
3.
4.
5.
6. Average atomic mass7. Spectrometers are also used to
II. The Mole
A. MoleB. 1 mole of any element is equal to
C. Can convert many ways
1. Moles to mass or mass to moles
2. Moles to atoms/molecule or molecules/atoms to moles
3. Grams to atoms/molecules or atoms/molecules to grams
III. Molar Mass
A. Molar mass-
B. Units of
IV.
Percent composition of compounds
A. Find mass percents of each element
1.
2.
V. Determining the Formula of a Compound
A. Weigh a sample and decompose into its elements or react with
oxygen (burn) to produce known products
1.
2.
B. Changing % composition into a formula
1. Formulas represent
2. Assume you have
3. Convert
4. Convert
5. Find the smallest whole-number ratio of atoms in the
compound6. If numbers are not whole numbers,
7. Method provides empirical formula\
8. Molecular formulaa) Obtain empirical formula
b)
c)
d)
VI.
Chemical Equations
A. Chemical reactions- reorganization of atoms in one or more
substances
1. Chemical equation2. Bonds break and re-form3. All atoms that are present as reactants must
4. Balancing chemical equations-
B. Meaning of a chemical equation
1. Provide nature of reactants and products and relative
numbers of each
a) Relative number of each substance is known through
b) Physical states:
2. Tells us # of molecules, moles, grams, and in some cases
liters
VII. Balancing Equations
A. Before you do anything else, you should always determine if an
equation is balanced
B. Number of atoms of each element must be
C. The identities of the substances
D. Steps for balancing
1.
2.
3.
4.
E. Balancing- generally done by trial and error
F. Start with the most complicated molecules.
1. Save
VIII. Stoichiometric Calculations: Amounts of Reactants and Products
A. 1st thing to do in stoichiometry-
B. Convert from
C. Use a
D. Convert to
IX.
Calculations involving limiting reactant
A. Haber ProcessB. Limiting reagent (or reactant) –
C. Steps for calculations involving amounts of both reactants
1.
2. Convert the known quantities of reactants
3. Determine which reactant is limiting
a) Simple way:
b)
c)
d) Other way:
e)
4. Theoretical Yield- amount of product formed when the
limiting reactant is completely used up
a) Maximum possible amount of product
5. Actual Yield- the amount of product actually obtained in an
experiment
6. Percent Yield