Exam 1

Hydrochloric Acid

Strong acid, chloride ion

Hydrochloric acid

pKa = -7

Sulfuric acid

Strong acid, hydrogen sulfate

Sulfuric acid pKa

-3

Hydronium

Strong acid, water

Hydronium pKa

-1.7

Hydrofluoric acid

Strong acid, fluoride ion

Hydrofluoric acid pKa

3.17

Formic acid

Strong acid, formate

Formic acid pKa

3.76

Acetic acid

Strong acid, acetate ion

Acetic acid pKa

4.74

Hydrocyanic acid

Strong acid, cyanide ion

Hydrocyanic acid pKa

9.22

Ammonium

Weak acid, ammonia

Ammonium pKa

9.24

Water

Weak acid, hydroxide

Water pKa

15.7

Ethyl alcohol

weak acid, ethoxide

Ethyl alcohol pKa

15.9

Acetone

Very weak, enolate

Acetone pKa

20

acetylene

very weak acid, acetylide

acetylene pKA

25

ammonia

not acidic, amide

ammonia pKa

38

methane

not acidic, methyl

methane pKa

50

Formal charge

valence electrons - 1/2(shared electrons) - unshared electrons

Isomer

same formula but different shape

VESPR theory

valence shell electron pair repulsion theory, because electron pairs repel, molecules adjust their shapes so that valence electrons pairs are as far apart as possible

areas of electron density

unbonded pair, single bond, double bond, triple bond

Tetrahedral

4 bonds, 0 lone pairs, 109.5

Trigonal planar

3 bonds, 120 degrees

linear

2 bonds, 180

dipole moment

a property of a molecule whose charge distribution can be represented by a center of positive charge and a center of negative charge

s orbital

spherical

p orbital shape

peanut

molecular orbital theory

accounts for the allowed states for electrons in molecules

Linear combination of atomic orbitals

technique for combining atomic orbitals to create molecular orbitals

Constructive waves

waves that have the same sign

Destructive waves

waves with opposite signs

sigma orbital

lies along the axis between two bonded atoms

pi orbital

when the p-orbitals of carbon atoms in double bonds overlap, each containing one electron, forming an electron density cloud above and below the bond

resonance structure

one of the two or more equally valid electron dot structures of a molecule or polyatomic ion

resonance hybrid

the actual structure of a molecule that is intermediate between two or more resonance structures

alkane

a hydrocarbon containing only single covalent bonds

alkane formula

CnH2n+2

saturated hydrocarbon

A hydrocarbon in which all the bonds between carbon atoms are single bonds

unsaturated hydrocarbon

A hydrocarbon in which one or more of the bonds between carbon atoms is double or triple

alkenes

Hydrocarbons with one or more carbon-carbon double bonds

Alkyne

carbon-carbon triple bond

Intermolecular force

forces of attraction between molecules

Ionic

metal and nonmetal

Hydrogen bonding

the intermolecular force in which a hydrogen atom that is bonded to a highly electronegative atom is attracted to an unshared pair of electrons of an electronegative atom in a nearby molecule

Dipole-dipole

attractions between oppositely charged regions of polar molecules

van der Waals

a slight attraction that develops between the oppositely charged regions of nearby molecules

London dispersion force

the intermolecular attraction resulting from the uneven distribution of electrons and the creation of temporary dipoles

constitutional isomer

compounds with the same molecular formula but different connections among their atoms

IUPAC system

Systematic method for naming chemical compounds.

IUPAC naming rules

1. Find the longest carbon chain (if there's a tie, the one with the most substituents is the parent chain)

2. The terminal carbon closest to a substituent is numbered #1 (if there is a tie, go with the terminal carbon closest to the next substituent)

3. Order the substituents alphabetically and give each one a number to match the carbon it is bound to

4. If more than one of the same substituent is present use the prefixes di, tri, tetra, etc. (e.g.- 2,2,3-trimethylbutane)

5. Hyphens are placed before and after substituent numbers but NOT between standard prefixes (Use hyphens to separate numbers from words, use commas to separate numbers from numbers, and just smash all adjacent words together)

6. Do NOT consider prefixes when alphabetizing within the IUPAC name if they 1) represent a number (di, tri, tetra, etc.) or 2) include a hyphen (sec-, tert-, etc.) Do include other prefixes (isopropyl, isobutyl, etc.)

primary (1)

1 carbon attached

secondary (2)

2 carbons attached

tertiary (3)

3 carbons attached

quaternary (4)

4 carbons attached

isopropyl

isobutyl

isopentyl

strain

any force, conformation, or angle within a molecule that destabilizes the molecule and raises its relative energy

angle strain

results when bond angles deviate from their ideal values by being stretched or compressed

torsional strain

results when cyclic molecules must assume conformations that have eclipsed interactions

steric strain

the interference between two bulky groups that are so close together that their electron clouds experience a repulsion

dihedral angle

the angle between two specified groups in a Newman projection

H/H eclipsing interactions

1.0 kcal/mol

gauche

in Newman projections: a 60 degree dihedral angle between a group on the front carbon and a group on the back carbon

CH3/CH3 gauche

0.9 kcal/mol

cycloalkane

an alkane that is a ring or cyclic structure

stereoisomerism

isomers that differ in their spatial connectivity

cis

when the substituents come off the ring in the same direction

trans

when substituents are on opposite sides of the ring

ring strain

Energy created in a cyclic molecule by angle strain, torsional strain, and nonbonded strain; determines whether a ring is stable enough to stay intact.

reaction coordinate diagram

shows the energy changes that take place during the course of a reaction

flagpole interaction

For cyclohexane, the steric interactions that occur between the flagpole hydrogen atoms in a boat conformation.

axial

aligned with an axis

equatorial

point away from the ring

1,3-diaxial interaction

the strong steric strain between two axial groups on cyclohexane carbons with one carbon between them

functional group

group of atoms within a molecule that interacts in predictable ways with other molecules

haloalkane

compounds with halogen bonded to an sp3 hybridized carbon

alcohol

contains an oxygen singly bonded to an alkyl group and a hydrogen, the OH group is referred to as a hydroxyl group

ether

contains an oxygen singly bonded to two alkyl groups

amine

contains a nitrogen with three bonds to either sp3-hybridized carbons or hydrogens, the NH2 group is referred to as an amino group

aldehyde

contains a carbonyl group between hydrogen and an alkyl group for H

ketone

contains a carbonyl group between two alkyl groups

carboxylic acid

contains a carbonyl group between a hydroxyl group and an alkyl group for H

ester

contains a carbonyl group between an alkoxy group and an alkyl group