Chapter 2 Flashcards
intermolecular force: dipole-dipole
- 2 polar molecules (determined by electronegativity)
- positive and negative ends attract
intermolecular force: London dispersion
- non polar molecules
- electrons distort briefly and will be temporarily be dipole
- very weak bond
intermolecular force: hydrogen bonding
- O, N, F bond with Hydrogen
- H from one molecule bonds with the a lone pair of electrons on another molecule
- very strong
effect of branching on boiling points
- long chain=increased boiling point
- more branching = decreased boiling point
effect of intermolecular force on boiling point
hydrogen bonding=increased boiling point
polarity effects on solubility
- like dissolves like
- polar dissolves polar
- non polar dissolves non polar
define hydrocarbons
compounds composed of only carbon and hydrogen
functional group: alkane
single bond
hybridization of alkanes
sp3
functional group: alkenes
double bond
hybridization of alkenes
sp2
functional group: alkynes
triple bond
hybridization of alkynes
sp
what does the prefix “cyclo-“ mean?
the structure forms a ring
understand naming alkanes!!
- prefix = number of carbons
- suffix = -ane
- lower numbers are better and use alphabetical order
functional group: alcohol
-OH
functional group: ether
-O-
functional group: aldehyde
-COH
functional group: ketone
-CO
functional group: carboxylic acid
-COOH
functional group: amine
-NH2
- NO OXYGEN
functional group: amide
- NH2O
- DO HAVE OXYGEN
functional group: Nitriles
-CN
define Acid/Base reaction
exchanging of a proton
define nucleophile
- Lewis Base
- negative or neutral
- accepts proton and donates electron
define electrophile
- Lewis Acid
- positive or neutral
- donates a proton and accepts electron
what is special about the Arrhenius Acid/Base Reaction?
REACTION MUST HAPPEN IN WATER
Arrhenius Acid
dissociates in water to give H3O+ ions
- has HO3 in it somewhere
Arrhenius Base
dissociate in water to give OH
- has OH in it somewhere
Bronsted-Lowry Acid
donate a proton (H+)
- has a hydrogen in it
Bronsted-Lowry Base
accepts a proton
- can be negative
Conjugate Acid
when a base accepts a proton
Conjugate Base
when an acid donates a proton
Lewis Acid
can accept an electron
- usually positively charged
Lewis Base
can donate and electron
- usually negatively charged
signs of reactivity
- formal charge
- partial charge
- pi bonds
- sterics
define pKa
measurement of a molecule to donate protons
- 16 = neutral
- -10 = very acidic
- 50 = good base
water pKa
15.7 pKa
alcohol pKa
about 16 pKa
carboxylic acid pKa
5 pKa
acid base equilibrium steps
- identify Lewis acid and base
- label conjugate acid and base
- compare the acidity/pKa of the Lewis acid to the conjugate acid
**products or reactants will be favored depending on where the stronger acid is
Acidity Factors: electronegativity
more electronegative, more acidic
Acidity Factors: size
larger in size (down columns on the periodic table), the more acidic
Acidity Factors: inductive effects
the stabilizing properties that electronegative atoms NOT connected to the acidic hydrogen:
- strength (F>Cl>Br>I)
- number (more=more acidic)
- proximity (closer=more acidic)
Acidity Factors: Hybridization Effects
- sp = 25 pKa (alkyne)
- sp2 = 44 pKa (alkene)
- sp3 = 50 pKa (alkane)
Acidity Factors: resonance
the donation of a proton leads to resonance structures that conjugate base will be more stable and the molecule will be a better acid
