Chemistry 261 Final exam notes
Methane (CH4) Ethane (C2C6). Propane(C3H8)
Single bond: Double bond: ethylene
Ex: CO2 formal aldehyde: CH2O
Acetylene: C2H2 Hydrogencyanide:
Calculation for double bind equivalent:
Ex: C3H6: N=9
Number of double bond equivale: 1= one ring, double bond 2=2 rings, 2 double bonds, 1 triple
Dot structure “single bond” CH4:
Double bond: C2H2
Ionic Bond: Na --> e( Na ) Cl --> e( Cl )
Atomic orbital: volume of space with high probability of finding an electron “1s,2s,2p, 3p,4s”
Sp3 Hybridization Sp2 hybridization
Formal charges: the hypothetical charge that would result if all bonding e- are shared equally.
Formula: (#of ve in a free atom) – (# of be in bonded atom)
Oxidation state: the hypothetical charge that would result if all binding e- are assigned.
Formula: (# of be in a free atom) – (# of be in a bonded atom)
Increase stability to delocalize, can't localize anion, decrease stability
Resonance structure pattern Resonance structure of Benzene
Resonance structure and hybridization Summary of hybridization
1) Sp: linear geometry 180, alkynes, at each triple Bond of c, 2s hybrid and 2p hybrid.
2) Sp2: trigonal planar 120, Allene, at each double Bond, 3s, 1p
3) Sp3: tetrahedral 109.5, alkanes, 4s
Families of carbon compound
Hydrocarbon: representing alkanes, alkenes, alkynes
Alkanes: saturated, no multiple bond between c atoms (-ane)
Alkenes: unsaturated, contain at least one c bond, (- ene)
Alkynes: unsaturated, at least 1 triple bond, (-ynes)
Aromatic compound: contain a special type of ring, the most common example is benzene ring.
Unsaturated cyclic hydrocarbon known as aromatic compounds. This benzene compound is a six
membered ring with alternating single and double bond called Kekule structure. (120)
Benzene is a resonance hybrid of structure a and b
Common and specific arrangement of atoms that import predictable reactivity and properties to a
Alkynes group: groups that would be obtain by removing a hydrogen atom from alkane.
Alkane Alkyl Group
Propane can be derived into 2 groups. Removal of a group; removal of hydrogen from the middle carbon
atom gives a group that is, isopropyl group. Removal of hydrogen from one of the end carbon gives a
group that is, propyl group.
Symbol R: is used to a general symbol to represent any alkyl group. Ex: R might be a methyl group, an
ethyl group, propyl, isopropyl.
Methyl Ethyl Propyl isopropyl
Phenyl and benzyl group When a benzene ring is attached to some other group of atoms is a molecule, it is phenyl group.
- The combination of a phenyl group and methylene group-C ( H2) is called benzyl group. (Phenyl
group with benzyl ring)
Alkyl halides or haloalkanes (haloalkanes) R-X
Alkyl halides are compound in which a halogen atom ( fluorine, chlorine, bromine, iodine). Replaces a
hydrogen atom of an alkane with a halogen.
The generic formula for an alkyl halide is R-X where X is halogens and R is alkanes.
Alkenyl Halide: a compound with a halogen atom bonded to an alkenes group carbon.
An aryl halide: a halogen atom bonded to an aromatic ring such as benzene ring.
Alcohol and phenols R-OH, -ol ending
Methyl alcohol (methanol) has the structural formula CH3OH and is the simplest form of organic
• The characteristic functional group of this family is (-OH) group attached to an sp3 hybridized
• As hydroxyl derivatives strives of alkenes: ethane molecules in which one hydrogen has been
replaced by a hydroxyl group.
• An alkyl dedicates of water: one hydrogen has been replaced by ethyl group.
Three groups of alcohols: this classification is based on the degree of substitution of the carbon to which
the hydroxyl group is directly attached.
Primary alcohol: carbon has only one other carbon attached to it.
Secondary alcohol: the carbon that bears the hydroxyl group also has 2 other carbon atoms attached.
Tertiary alcohol: carbon atom bears the hydroxyl group has 3 other carbon attached to it.
Phenol: a hydroxyl group is bonded to a benzene ring the combination of the ring and the hydroxyl Ethers: Ethers have general formula R-O-R or R’-O-R where R’ = alkyl or phenyl group. Ethers can be
thoughts as derivatives of water in which both hydrogen atoms have been replaced by alkyl group. The
bond angle at the oxygen atom of an ether is only slightly larger than the water.
Naming ethers: name the 2 alkyl groups that attached to the oxygen atoms in an alphabetical orders, and
add the word ether. If the 2 alkyl groups are he same, we used prefix (dimethylether)CH3CH2 –O– CH2CH3
Amines: May be considered as organic derivatives of ammonia
This classification based on the number of organic groups that are attached to the nitrogen atoms.
Note: Isopropylamine is a primary amine even though its Nh2 groups is attached to a secondary carbon
atom. It is a primary amine because only one organic group is atatched to the nitrogen atom.
• The nitrogen atom of an amine can be considered to be sp3 hybridized with the unshared electron
pair occupying one orbital.
Aldehydes and Ketones
Aldehydes and ketones both contain the carbonyl group (C=O).
Ketones: the carbonyl group of ketone is bonded to 2 carbon atoms. Have a trigonal planar arrangement of
groups around carbonyl atom.
Carboxylic acids, esters and Amides
A. Carboxylic acids: carbonyl group + hydroxyl group
B. Esters: RCO2R' or RCOOR', where a carbonyl group is boned to an alkoxyl (-OR) group.
C. Amides: RCONH2, RCONHR', RCONR'R'' , where the carbonyl group bond to the nitrogen atom
baring hydrogen and/ or alkyl group. Nitriles: R—CN. Sp hybridized. Acentronitrile: Butanentrile:
Cyclic nitriles are named by adding –carbonitrile to the name often ring system to which the -CN group is
Benzenecarbonitrile (benzonitrile, C6H5CN):
Lewis Acid/ Bases
Acids are electron pair acceptors:
Base are electron pair donors:
Infrared spectroscopy depends on the interaction of molecules or atoms with electromagnetic
radiation. IR causes atoms and groups of atoms of organic compounds to vibrate with increased amplitude
about the covalent bonds that connect them.
The functional groups of organic molecules include specific arrangements of bonded atoms ,absorption of
IR radiation will occur at specific frequencies characteristic of the type of bond and atom presented.
Formula for frequency:
Formula for energy of absorption (E): inversely proportional to frequency of radiation (v)
Molecules movement: Two atoms joined by a covalent bond can undergo a stretching where atoms move
back and forth as if joint by spring.
Stretching vibration: Systematic stretching:
Asymmetric stretching: Scissoring (in plane):
Rocking (in plane): Wagging (out of plane):
Twisting (out of plane:
Frequency related mass
1. The mass of bonded atoms: light atoms vibrate at higher frequencies than heavier ones
2. The relative stiffness of the bond triple > double > single
Alkanes: methane (CH4), Ethane (CH3CH3), Propane: CH3CH2CH3, Butane: CH3CH2CH2CH3
Pentane: C5 Hexane: C6 Heptane: C7 Octane: C8 Nonane: C9 Decane: C10 Butane: C4H10 Isobutane: C4H10