UNIT IX Lesson #2 Polar Vs Non Polar

Review BOND TYPEWHAT TO LOOK FOR... INTRAMOLECULAR BONDS ( within the molecule itself) IONIC BONDMade up of metal and nonmetal (or recognizable ions) COVALENT BONDMade up of nonmetal and nonmetal INTERMOLECULAR BONDS ( between molecules) HYDROGEN BONDLook for HF or any molecule having OH or NH in its formula DIPOLE-DIPOLE FORCELook for an asymmetric molecule LONDON FORCEAlways present

L OOKING AT STRUCTURES TO DETERMINE POLARITY Other than having permanent dipoles, if we look at the structure of the molecules we can determine if they will be polar molecules, or non- polar molecules.

Molecular Polarity Polar (H 2 O)

Molecular Polarity Non-Polar BF 3 Boron Trifluoride

Polar Vs Non-Polar Which of the following are expected to be polar and which are expected to be nonpolar?? Methane (CH 4 ) Hydrogen Fluoride (HF)

Polar Vs Non-Polar nonpolar = symmetrical polar = asymmetrical (if one end of the molecule differs from the other) Methane Hydrogen fluoride

M ORE EXAMPLES … Borane (BH 3 ) BeF 2 CH 3 Cl SF 2

S HAPES OF M OLECULES C 2 H 6 C 3 H 8 Hydrocarbons are always non-polar Hydrocarbons are compounds that contain only carbon and hydrogen.

M ETHANOL CH 3 OH AND ETHANOL CH 3 CH 2 OH

FYI: F OR YOUR INFORMATION ! Methanol has a high toxicity in humans. If as little as 10 mL of pure methanol is ingested, it can break down into formic acid, CH 2 O 2 which can cause permanent blindness by destruction of the optic nerve! Ethanol (Ethyl alcohol) It is the main type of alcohol found in alcoholic drinks. Ethanol is used as a solvent, an antiseptic, a fuel, in modern thermometers.

HOMEWORK PAGE 201 QUESTION 10 AND YES, THAT’S IT!