HELLO MR.DOKTOR

today you told us that we'd be having our chapter test next class.. whoooopeee!
You gave us this class to review. we went over the worksheet. and you handed us a solution chemistry review

* remember to know intermolecular and intramolecular*
inter--> outside
intra-->inside

Today in class we continued learning about polarity and nonpolarity

• MOLECULAR AND INTERMOLECULAR BONDS
Intermolecular means the bonds outside molecules
- Intramolecular means bonds inside molecules

• Polarity is the result of intermolecular bonds
• Most bonds are electrostatic:

1. LONDON DISPURSION FORCE (L.D.F)
- Experienced by all molecules
- Result of electrons pushing on each other
- Weakest of all forces

- As the number of electrons increase L.D.F increases

- Comparison between the atoms Aluminum and Argon
Q:Which molecule will have a longer l.d.f?
A: Argon because it’s got more electrons. Which ever has more electrons experiences a longer LDF
- As the number of electrons increase L.D.F increases.



2. Dipole- Dipole
- Dipoles are partial separation of charges
- L.D.F is a type of temporary dipole
- Why is it a temporary dipole? Because electrons are always moving. Electrons always moving they don’t necessarily have to be in the same place.
- Some molecules have a permanent dipole
- These are polar molecules
- Polarity is determined by electrons affinity (how much an atom wants electrons)
- Electrons affinity is called electronegativity
- Electronegativity is highest on the top right and lowest on the bottom left


- Electronegativity is highest on the top right and lowest on the bottom left.
- A bond between two atoms/molecules with different electronegativities results in a dipole-dipole bond.

• Whats a dipole dipole strength between the two molecules Cl -Cl? None! Because none of them are polar
• Polar= dipole dipole
EXAMPLES: which bonds will result in a dipole-dipole force?

1.H-Clyes
2. O-Hyes
3. F-F No
4. O-Cl yes
5. I-Br yes

Are the following compounds polar or nonpolar?
1. CHCl3polar
2. 2. BI2Brpolar
3. C2H4non polar
4. C2H2Cl2non polar

DIPOLE DIPOLE FORCES ARE WEAK VERSIONS OF IONIC BONDS
COMPOUND Boiling Point Number of electrons
N2 -196 degrees celcius 14
O2 -183 16
NO -152 15
ICL 97 70
Br2 59 70

homework: questions 1 & 2 on worksheet

Today in class we learned about the polar and non polar solvents

Polar and non-polar solvents

• Polar substances have an unequal distribution of changes.
DRAW IMAGE



• Non- polar substance have equal change distribuation
DRAW IMAGE

and we did a lab - the objective was to determine if Glycerin is Polar or non-polar.
after mixing the test tubes, we noticed that the solvents water sugar- after mixing hte two dissolved. also the salt. some of the test tubes changed colors, for ex. iodine and the paint thinner. also after mixing iodine and water: it just changed colors from clear to brown, and it did not dissolve.

in the end we have conconluded that glycerin is polar because it mixed with water which is also a polar substance.
non polar can only react with non polar.
homework: FINISH THE LAB

April 12, 2010

Electrical conductivity in solutions requires charged ions to be transferred.
Ionic solutions dissociate, or form ions so they always conduct
NaCl(s)- Na(aq) + Cl(aq)
Molecular substances do not (usually) dissociate.
C12 H22 O11 h2o- C12 H22 O11 (aq)
BaCl2 (s) h2oBa(aq)+2 +2Cl- (aq)
CH3COOHCH3COO- +H+
96% 4%

Follow the chart to determine conductivity
Is it a metal if yes it is conductive

Homework:

1) Al (s)
2) H2so4(aq)
3) I2(s)
4) Br2(1)
5) Mg(OH)2(aq)
6) CH4(g)
7) PCL3(1)
8) ZnBr2(s)
9) NH3(aq)
10) Cr(NO3)2
11) H2O2
12) Cu3(PO4)2