By Graham Solomons, Craig Fryhle, and Scott Snyder
- 1 Bonding and Molecular Structure
- 2 Families of Carbon Compounds
- 2.1 Hydrocarbons
- 2.2 Polar Covalent Bonds
- 2.3 Functional Groups
- 2.4 Alkyl halides or haloalkanes
- 2.5 Alcohols and Phenols
- 2.6 Ethers
- 2.7 Amines
- 2.8 Aldehydes and Ketones
- 2.9 Carboxylic Acids, Esters, and Amides
- 2.10 Nitriles
- 2.11 Physical Properties and Molecular Structure
- 2.12 Interpreting IR Spectra
- 3 Acids and Bases
- 4 Nomenclature and Conformations of Alkanes and Cycloalkanes
- 5 Stereochemistry
- 6 Nucleophilic Reactions
- 7 Alkenes and Alkynes I
- 8 Alkenes and Alkynes II
- 9 NMR and Mass Spectometry
Bonding and Molecular Structure
Families of Carbon Compounds
Functional groups are arrangements of atoms that have predictable properties.
Hydrocarbons contain hydrogens and carbons.
Alkanes have single bonds. Alkenes have at least one C-C double bond. Alkynes have at least one C-C triple bond. Aromatic compounds have a special type of ring.
Compounds like alkanes are saturated because they have the max num of hydrogens. Others are unsaturated.
Benzenes can be represented by resonance between the two equivalent kekule structures.
Polar Covalent Bonds
Polar covalent bonds are the result of differences in electronegativity.
Alkyne fg is c-c triple bond. Alkene is c-c double bond. Alkanes do not have f groups inherently.
Alkyl groups are used for naming compounds. They are when we remove h from alkane. (methane -> methyl, etc.)
Propane with h from end is propyl. From center is isopropyl.
R represents any alkyl group.
When benzene is attached to another group it is called a phenyl group. Phenyl and methylene is called benzyl group.
Alkyl halides or haloalkanes
Haloaklkanes are R-X where is is a halogen. These are called primary, secondary, or tertiary based on how many other Cs are bonded to the carbon the halogen is on.
Alcohols and Phenols
Methanol is CH3OH. Alcohols are hydroxyl derivatives of alkanes or alkyl derivatives of water. There are primary/secondary/tertiary forms in the same vein as the haloalkanes.
When a hydroxyl is bound to benzene it's called a phenol. It is considered a different functional group.
Ethers are R-O-R or R-O-R'. These are like water with both hydrogens gone. The angle is slightly larger than water.
Amines are nitrogens. They are 1n/2n/3n based on the number of groups attached to the N.
The n is sp3 hybridized so that the unshared pair is relatively exposed.
Aldehydes and Ketones
C=O. Aldehydes bonded to one H and one C except in formaldehyde. Ketones have two Rs bonded. Trigonal planar.
Carboxylic Acids, Esters, and Amides
Carboxylic acids have a carbonyl bonded to hydroxyl and have O=C-OH, -R
Esters have RCO2R' where carbonyl is donded to alkoxyl (-OR) group.
Amides have RCONH2, like a carbonyl bonded to nitrigen.
Have R-C triple bonded to N. (R-CN)
C and N are sp. Acyclic nitriles add -nitrile to the name of the hydrocarbon. The C bound to the N gets #1. Cyclic nitriles are denoted by -carbonitrile.
Physical Properties and Molecular Structure
Melting point and boiling point are key properties. Temperatures of phase changes are indicative of intermolecular force strength.
Ionic compounds are super strong because the order of the lattice is so great.
Van der waals forces: dipole-dipole, hydrogen bonds, dispersion forces.
Dipole-dipole: permanent dipole moments of separate molecules interact.
Hydrogen bonds are very strong dipole attractions when Hydrogens bound to strongly EN atoms interact with lone pairs on super EN atoms.
Symmetrical molecules have abnormally high melting points.
Dispersion is caused by the movement of electrons creating small temporarily dipoles, causing adjacent molecules to form dipoles. This produces attraction. Magnitude depends on the polarizability of the atoms. Large atoms are easier to polarize than small ones because the electrons are more loose.
Relative surface area is also important because molecules need to be close to each other in as many places as possible.
Boiling points are the temperatures at which vapor pressure equals atmospheric. The stronger the imfs, the higher the bp. Molecular weight, shape, and SA also matter because more thermal energy is required to shoot them out.
Solubilities also depend on imfs. Like dissolves like.
Water is a good silvent because it can form strong bonds with ionic things.
Miscible means substances are soluble in all proportions.
Hydrophobic and hydrophilic mean whether something likes to dissolve in water.
For nonpolar hydrocarbons to be in water, the waters have to form a more ordered structure which goes against entropy.
Compounds with one hydrophilic group and with 1-3 C are H2O soluble, 4-5 borderline, 6+ insoluble.
ion-dipole is moderate strength.
IR spectroscopy lets you detect functional groups.
It depends on radiation vibrating molecules. The molecules absorb at specific characteristic frequencies. Vibrations are quantized.
Positions of bands are specified in wavenumbers (cm^-1)
Covalently bonded atoms have only particular vibrational levels. The bonds can stretch or contract. The frequency of stretching vibration depends on masses of atoms and stiffness of bonds.
Interpreting IR Spectra
IR spectra contain lots of info. sp > sp^2 > sp^3 bond stiffness.