Chapter 2: Families Of Carbon Compounds

Front 1

Hydrocarbons

Back 1

* Compounds that only contain carbon and hydrogen atoms
* Ex. Methane and Ethane

Front 2

Alkanes

Back 2

* Hydrocarbons
* Do not have multiple bonds between carbon atoms
* Specified by -ane ending
* Primary sources are natural gas and petroleum

Front 3

Alkenes

Back 3

* Hydrocarbon
* At least one carbon-carbon double bond
* Specified by -ene ending

Front 4

Alkynes

Back 4

* Hydrocarbon
* Contains at least one carbon-carbon triple bond
* Specified by -yne ending

Front 5

Aromatic Compounds

Back 5

* Hydrocarbon
* Special type of ring
* Ex: benzene ring
* No special ending

Front 6

Saturated Compounds

Back 6

* Molecules that contain only single bonds

Front 7

Unsaturated Compounds

Back 7

* Compounds with multiple bonds

Front 8

Methane

Back 8

* The simplest alkane
* Gas in ambient temperature
* CH4

Front 9

Ethene

Back 9

* Alkene
* C2H4

Front 10

Ethyne

Back 10

* Alkene
* C2H2

Front 11

Benzene

Back 11

* Aromatic compounds
* C6H6
* Bond lengths are equal
* 120 degree bond angles

Front 12

Kekule Structure

Back 12

* Six membered ring with alternating double and single bonds
* Benzene
* Bond lengths are equal

Front 13

Molecular Orbital Explanation for Benzene Ring

Back 13

* Carbon atoms are sp2 hybridized
* P orbitals overlap with the p orbitals on either side of the carbon
* Six electrons associated with p orbital are delocalized about all six carbon atoms of the ring
* Explains how carbon-carbon bonds of the benzene molecule are the same length

Front 14

Polar Covalent Bond

Back 14

* Electronegativity differences exist between 2 covalently bonded atoms
* Electrons are not shared equally

Front 15

Dipole Moment (mu)

Back 15

* Product of the charge in electrostatic units (esu) and the distance that separates them in cm

Front 16

Debye (D)

Back 16

* 1e-18 esu-cm
* 3.336e-30 C-m

Front 17

Functional Groups

Back 17

* The particular group of atoms in a molecule that primarily determines how the molecule reacts
* Often contain atoms with different electronegativity values and unshared electrons

- Alkanes do not have a functional group

Front 18

Heteroatoms

Back 18

* Atoms that form covalent bonds and have unshared electron pairs
* O, N, S

Front 19

Map of Electrostatic Potential (MEP)

Back 19

* More negative surface colored red
* More positive colored blue
* Plotted at low electron density surface it gives indication of molecule's overall shape

Front 20

Polar Molecule

Back 20

Molecule with a dipole moment

Front 21

Alkyl Groups

Back 21

* The designation given to afragment of a molecule hypothetically derived from an alkane by removing a H atom
* end in yl

Front 22

Methyl Group

Back 22

- Alkyl Group

Front 23

Ethyl Group

Back 23

- Alkyl Group

Front 24

Propyl Group

Back 24

- Alkyl Group

Front 25

Butyl Group

Back 25

- Alkyl Group

Front 26

Isopropyl Group

Back 26

- Removal of the hydrogen atom from the middle carbon of propane

- Alkyl Group

- CH3CHCH3

Front 27

The symbol R

Back 27

* General symbol to represent any alkyl group

Front 28

R-H

Back 28

General form of alkane

Front 29

Phenyl Group

Back 29

- When benzene ring is attached to some other group of atoms in a molecule

- Alkyl Group

Front 30

Benzyl Group

Back 30

- Combination of a phenyl group and a methylene group

- Alkyl Group

Front 31

Methylene group

Back 31

-CH2-

Front 32

Alkyl Halides (haloalkanes)

Back 32

* Compounds in which a halogen atom replaces a hydrogen atom of an alkane
* Classified as primary secondary or tertiary, based on the carbon atom in which the halogen is attached

Front 33

Primary Alkyl Halide

Back 33

* Attached to primary carbon atom

Front 34

Secondary Alkyl Halide

Back 34

* Attached to secondary carbon atom

Front 35

Tertiary Alkyl Halide

Back 35

* Attached to tertiary carbon atom

Front 36

Primary Carbon Atom

Back 36

Attached to only one other carbon

Front 37

Tertiary Carbon Atom

Back 37

Attached to three other carbon atoms

Front 38

Alkenyl Halide

Back 38

- Compound with a halogen atom bonded to an alkene carbon

Front 39

Aryl Halide

Back 39

- Compound with a halogen atom bonded to an aromatic ring

Front 40

Methyl Alcohol (Methanol)

Back 40

* CH3OH
* Simplest alcohol

Front 41

Alcohol

Back 41

* Characterized by an hydroxyl group (-OH) attached to an sp3 hybridized carbon atom
* Can be seen as an ethane molecule with one H replaced by an hydroxyl group
* Or as a water molecule in which 1 H has been replaced by an ethyl group
* Classified based on degree of substitution to which the hydroxyl group is directly attached

Front 42

Ethyl Alcohol (ethanol)

Back 42

* CH3CH2OH

Front 43

Phenol

Back 43

* Hydroxyl group is bonded to a benzene ring
* Differ from alcohol in terms of relative acidity
* Distinct functional group

Front 44

Ether

Back 44

* General Formula R-O-R', where R' is a different alkyl (or phenyl) group than R
* Can be thought of as water in which both H atoms have been replaced by alkyl groups
* Bond angle at O is slightly larger than water

Front 45

Amines

Back 45

* Can be considered an organic derivative to ammonia
* Classified by the number of organic groups that are attached to the nitrogen atom
* Trigonal pyramidal shape
* Sp3 hybridized

Front 46

Primary Amine

Back 46

Front 47

Secondary Amine

Back 47

Front 48

Tertiary Amine

Back 48

Front 49

Bonding Order for MO Theory (Ch. 1)

Back 49

- IF 0, two atoms are not bonded

1 = single bond

2 = double bond

3 = triple bond

-

Front 50

Carbonyl group

Back 50

Group in which a carbon atom has a double bond to O

Front 51

Aldehyde

Back 51

* Contains carbonyl group bonded to one H and one C
* Except for formaldehyde which is the only aldehyde with 2 H's
* Trigonal planar arrangement of groups around the carbonyl carbon atom

Front 52

Ketone

Back 52

* Contains a carbonyl group bonded to 2 carbon atoms
* Trigonal planar arrangement of groups around the carbonyl carbon atom

Front 53

Amides

Back 53

* Contain a carbonyl group bonded to a N atom bearing H and or alkyl groups

Front 54

Carboxyl group

Back 54

* Carbonyl and hydroxyl groups

Front 55

Carboxylic Acids

Back 55

* Contain a carbonyl group bonded to a hydroxyl group

Front 56

Esters

Back 56

* Contain a carbonyl group bonded to an alkoxyl (-OR) group
* Can be made from carboxylic acid and an alcohol via acid catalyzed loss of water molecule

Front 57

Formic Acid

Back 57

Carboxylic Acid

Front 58

Acetic Acid

Back 58

Carboxylic Acid

Front 59

Benzoic Acid

Back 59

Carboxylic Acid

Front 60

Alkoxyl group

Back 60

* -OR group

Front 61

Ethyl Acetate

Back 61

* Important solvent
* Ester

Front 62

Nitriles

Back 62

* R group bonded to a CN group
* C and N are sp hybridized
* Named by adding -nitrile to the name of the corresponding hydrocarbon
* C of CN group is assigned number 1

Front 63

Cyclic Nitriles

Back 63

Add suffix carbonitrile to name of the ring system

Front 64

Melting Point

Back 64

* the temperature at which an equilibrium exists between the well-ordered crystalline state and the more random liquid state
* Affected by polarity, H bonding
* More rigid and compact the molecule, the higher the melting point

Front 65

Ion-ion forces

Back 65

* Strong electrostatic forces of attraction between ions of opposite charges.
* These forces hold ions together in a crystal lattice.

Front 66

Boiling Point

Back 66

* The temperature at which the vapor pressure of a liquid is equal to the pressure above the surface of the liquid.
* Higher for ionic compounds
* Heavier molecules require more energy to reach velocities that allow it to escape the liquid phase

Front 67

Van der Waals forces

Back 67

* Intermolecular forces
* Electrical in nature
* Dipole-Dipole, Hydrogen Bonds, and dispersion forces

Front 68

Dipole-dipole forces

Back 68

* Molecules that are not fully ionic but have a permanent dipole moment due to nonuniform distribution of bonding electrons
* Ex. Acetone and acetaldehyde

Front 69

Dispersion Forces (London Forces)

Back 69

* Results from temporary dipole due to instant nonuniform distribution of electrons in a non-polar molecule
* Polarizability of electrons in atoms involved increases magnitude
* Larger surface area of molecule increases magnitude

Front 70

Dispersion Forces - polarizability

Back 70

* How easily electrons respond to a changing electric field
* Electrons of larger atoms are more polarizable

Front 71

Dispersion forces - surface area

Back 71

* Longer, flatter cylindrical molecules have larger surface area
* Branched molecules have less

Front 72

Solubility

Back 72

* The extent to which a given solute dissolves in a given solvent, usually expressed as a weight per unit volume

Front 73

Ion-dipole forces

Back 73

* The interaction of an ion with a permanent dipole. Such interactions (resulting in solvation) occur between ions and the molecules of polar solvents.

Front 74

General Rules of Solubility

Back 74

* Polar and ionic solids are usually soluble in polar solvents
* Polar liquids are usually miscible.
* Nonpolar solids are usually soluble in nonpolar solvents.
* Nonpolar liquids are usually miscible.
* Polar and nonpolar liquids, like oil and water, are usually not soluble to large extents.

Front 75

Guidelines for Water Solubility

Back 75

* For compounds containing one hydrophilic group- thus capable of forming H bonds
* Compounds with 1-3 carbons are soluble
* Compounds with 4 or 5 carbons are borderline
* Compounds with 6 carbons or more are insoluble

Front 76

Hydrogen Bonds

Back 76

* Strong dipole-dipole interactions between H atoms bonded to strongly electronegative atoms (O, N, F) and nonbonding electron pairs on other such electronegative atoms
* Weaker than covalent bonds

Front 77

Infrared Spectroscopy

Back 77

* A type of optical spectroscopy that measures the absorption of infrared radiation. Infrared spectroscopy provides structural information about functional groups present in the compound being analyzed.
* Infrared radiation causes atoms or groups of atoms to vibrate with increased amplitude about the covalent bonds that connect them (not sufficient to excite electrons)
* For infrared absorption to occur, there must be a change in dipole moment

Front 78

Wavenumber (`V)

Back 78

* Number of waves per cm (cm-1)
* Specifies position of absorption bands in an IR spectrum
* Large wavenumber = larger freq which means higher the freq of the bond absorption
* Unlikely that 2 different compounds will have the same IR spectrum because spectra of even simple molecules have many peaks

Front 79

IR Spectroscopy Vibrations

Back 79

* Light atoms vibrate at higher freq than large atoms
* Stiffer the bond, the higher the freq of vibrations

Front 80

IR Spectra C-C Bonds

Back 80

* Single bonds give rise to weak peaks that are usually of little use in assigning structures
* Carbon-carbon double bonds give absorption peaks in the 1620-1680 (1/cm) region
* carbon-carbon triple bonds give absorption peaks between 2100 and 2260 (1/cm)
* If absent, the double or triple bond is symmetrically substituted (no dipole moment change)
* The stretchings of the carbon-carbon bonds of benzene rings usually give a set of characteristic sharp peaks in the 1450-1600 (1/cm) region

Front 81

IR Spectra Carbonyl Groups

Back 81

* carbon-oxygen double-bond stretching frequency of carbonyl groups gives a strong peak between 1630 and 1780 (1/cm)
* The exact location of the absorption depends on whether it arises from an aldehyde, ketone, ester, and so forth

Front 82

IR Spectra Hydroxyl Groups

Back 82

* absorption of an alcohol or phenol O─H group is in the 3200-3550 (1/cm) range, and most often it is broad
* Without IM hydrogen bonds, absorption has a much sharper peak at 3590-3650 (1/cm)

Front 83

IR Spectra Carboxylic Acids

Back 83

* The hydroxyl absorption of a carboxylic acid is often very broad, extending from 3600 to 2500 (1/cm)
* If both carbonyl and hydroxyl absorptions are present, good evidence for presence of a carboxylic acid group, but groups could be isolated in molecule

Front 84

IR Spectra Amines

Back 84

* Primary (1°) and secondary (2°) amines give absorptions of moderate strength in the 3300-3500 (1/cm) region
* Primary amines exhibit two peaks in this region due to symmetric and asymmetric stretching of the two N─H bonds.
* Secondary amines exhibit a single peak.
* Tertiary amines show no N─H absorption because they have no such bond.
* A basic pH is evidence for any class of amine

Front 85

IR Spectra C-H Bonds

Back 85

* C-H stretching peaks of H atoms attached with an sp orbital is about 3300 (1/cm)
* Order of bond strength sp > sp2 > sp3
* The carbon-hydrogen stretching peaks of hydrogen atoms attached to sp2-hybridized carbon atoms occur in the 3000-3100 (1/cm) region.
* The carbon-hydrogen stretching bands of hydrogen atoms attached to sp3-hybridized carbon atoms occur at lowest frequencies, in the 2800-3000 (1/cm) region

Front 86

Resonance Structures - Use of Curved Arrows

Back 86

- show the direction of electron flow in a reaction mechanism

- point from the source of an electron pair to the atom receiving the pair

- always show the flow of electrons from a site of higher electron density to a site of lower electron density

- never show the movement of atoms. atoms are assumed to follow the flow of electrons