CHEM EXAM 3 - C6, 7, 8 - VOCAB

Electronegativity

how much an atom wants electrons. It is technically defined as the average of an atom’s ionization energy and electron affinit

Partial +

low electron density, going to be attached to an element that is more electronegative than itself

Partial -

high electron density, going to be attached w/ an atom that has less electronegativity than itself

Nonpolar covalent bond

0 - < 0.4

Polar Covalent Bond

0.4-2.0

Ionic Bond

>2.0

Stereoisomers

Molecules that differ ONLY by the arrangements of atoms in space – atoms are

attached in the same order but they differ in their spatial positionin

Dipole Moment

higher polarity, or higher electronegative but cannot be the same

Pi bonds

have double bonds

Sigma bonds

have one bond

Cis Isomers

two groups of highest mass on double bond are on same side

Trans Isomers

two groups of highest mass on double bond are on opposite sides

Van Der Waals attractions/London Forces

1. weakest attractions

2. all molecules will have it

Dipole-dipole attractions

1. only polar

Hydrogen Bonding

1. strongest attractions

What happens to surface areas as it increases?

Boiling point increases, so van der waals increases

What happens as the carbon branch chain increases?

the boiling point decreases because surface area

decreases and therefore van der Waals attractions decrease. The more linear the molecule,

the more surface area and the higher the boiling point

Viscosity

It is the ability of a liquid or a solution to resist flow

= most surface area

Miscible

soluble in all proportions

What happens when there are more carbon atoms in the chain regarding water solubility?

The less water soluble the molecule becomes (chain must become short in order for it to be water soluble)

Solid —→ Liquid

Melting

Solid —→ Gas

sublimation

Liquid —→ Solid

freezing

Gas —→ Solid

Deposition

Liquid —→ Gas

Evaporation

Gas —→ Liquid

condensation