1. AP CHEMISTRY Summer Review Main Topics: Other:
Ch. 1/ sig. figs; conversion problems; density
Ch 2/ counting p+, no, & e-; naming & writing formulas
Ch. 3/ balancing eq.; % composition; empirical formulas stoichiometry conversions; limiting reagents; % Yield
Other:
Orbital diagrams; Dot notation

2. AP CHEMISTRY Significant Figures
The number of significant figures is the number of digits known with certainty plus one uncertain digit.
(Example: g means we are sure the mass is _______ but we are uncertain about the nearest g.)
•Final calculations are only as significant as the least significant measurement.
2.240 g

3. AP CHEMISTRY Sig. Fig. Rules
Nonzero digits are significant. (Nonzero Rule)
Example: 2.45 cm =________
2) Zeros between sig. figs. are significant. (Straddle Rule)
Example: 2.03 cm=_________
3) Zeros at the end of the number and after a decimal point are significant. (Righty-Righty Rule)
Example: cm=_________
3 s.f
3 s.f
4 s.f

4. Example: 10,300 grams = _____________
AP CHEMISTRY
4) Zeros at the end of a number before a decimal point are ambiguous…In some cases, a bar will be placed over a zero to eliminate the ambiguity or the number will be written in scientific notation. (Bar Rule)
Example: 10,300 grams = _____________
1.030 x 104 g = _________
5) If a number is known for certain, it is said to contain an infinite number of sig. figs. (Counting Rule)
Example: 60 seconds =1 minute
at least 3 s.f.
4 s.f
(60 is known to ∞ # of s.f.)

5. Significant Figures in Calculations
AP CHEMISTRY
Significant Figures in Calculations
• Multiplication and Division:
- Report to the least number of significant figures
Example: cm x 5.2 cm = _______
• Addition and Subtraction:
- Report to the least number of decimal places
Example: g – g = _______
32 cm2
19.1 g

6. AP CHEMISTRY Density • Density= mass/volume
-Density can be used as a “conversion factor” as well!
mass
Density
volume

7. AP CHEMISTRY Counting p+, no and e- • Protons = Atomic Number
Electrons = protons (in a neutral atom)
Neutrons = Mass # - protons
Mass Number = protons + neutrons
Gaining electrons gives an atom a (-) charge.
Losing electrons gives an atom a (+) charge.

8. AP CHEMISTRY Naming Compounds
Molecules– Contains only 2 nonmetals; covalent bonding.
General Format
Prefix (except mono)-name 1st element prefix-name 2nd element ending in –ide

9. AP CHEMISTRY

10. AP CHEMISTRY Naming Compounds Cation Name Anion Name
Ionic– Starts with metallic cation (or NH4+); ionic bonding.
General Format
Cation Name Anion Name
You will have to memorize the cation and anion symbols & charges!
We will have a quiz over them later!

11. AP CHEMISTRY
Naming Compounds
Acids– Starts with “H”

12. Example: C3H8 + __O2  __CO2 + __H2O
AP CHEMISTRY
Balancing Equations
You can only change coefficients!
Example: C3H8 + __O2  __CO2 + __H2O 5 3 4

13. AP CHEMISTRY Percent Composition
AW stands for the atomic weight of the atom from the periodic table.
FW stands for the formula weight of the compound.

14. AP CHEMISTRY Empirical Formulas
Helpful Rhyme: % to mass, mass to mole, divide by small, times ’til whole.

15. Stoichiometry Conversion Factors
AP CHEMISTRY
Stoichiometry Conversion Factors
1 mole = 22.4 L (at STP) = 6.02 x 1023 particles = FW (grams)
These conversions will take up to 3 steps and no more!
Always convert to moles of given first!

16. Stoichiometry Conversions- (gram to gram)
AP CHEMISTRY
Stoichiometry Conversions- (gram to gram)

17. Limiting Reagent (or Reactant)
AP CHEMISTRY
Limiting Reagent (or Reactant)
The reactant that runs out first “limits” the amount of product that can be formed.
Stoichiometry conversions can be done to determine which substance is the limiting reagent.

18. AP CHEMISTRY
% Yield
The amount of product predicted from stoichiometry taking into account limiting reagents is called the theoretical yield.
The percent yield relates the actual yield (amount of material recovered in the laboratory) to the theoretical yield:

19. Electron Configurations
AP CHEMISTRY
Electron Configurations
(Energy Level Diagrams)
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…

20. Electron Configurations
Silicon ↑ ↑ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓
(Energy Level Diagram) ↑ ↓
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…

21. AP CHEMISTRY Electron Dot Notation
The “Group A” number on the periodic table equals the # of valence electrons and therefore the # of dots.