Physicochemical Properties

Physical Property

property that does not affect the chemical

identity of a compound

Can be observed and measured without changing a compound's composition of matter

Any substance that has mass and can occupy space

Intrinsic

Qualitative

Extrinsic

Quantitative

Intermolecular Forces

Within molecules

Boiling points (BP) are dependent on the mass of the molecule; Solubility, the ability to dissolve into a solvent,is dependent on IMFs.

The strength of the interaction between

molecules is also dependent on the overall

shape of the molecule.

Hydrogen Bonding

complex interaction that includes dipole-dipole, as well as orbital interactions and the transfer of electron density between molecules.

These are the strongest of the IMFs

5 - 25 kJ/mol

range of hydrogen bonding

Dipole-Dipole (keesom)

arise from the attraction of

oppositely charged atoms (other than H) in

molecules. These molecules may have a

permanent dipole moment. Generally in organic

molecules they result from the presence of C-X

bonds where X is more electronegative to that of

C.

These are generally weaker than H-bonding

5-10 kJ/mol

Range of dipole dipole forces (keesom)

London dispersion

from the movement of electrons within a molecule. This natural motion can produce an uneven

distribution of the electrons (polarization of the

distribution) resulting in a temporary dipole

moment in the molecule. This will induce the

movement of electrons in adjacent molecules

producing a dipole moment in them.

These "induced" dipole moments are very brief as

they disappear when the electrons move to new

locations within the molecule, so they forces are

Boiling and melting point

are processes in which noncovalent interactions between identical molecules in a pure sample are

disrupted.

Branching

compound lowers its boiling point because it reduces the area of contact.

chemical reaction

occurs when one substance isconverted into another substance(s).

Reaction Mechanism

Define as the detailed knowledge of the steps

involved in a process in which the reactant

molecules change into products.

bond fission

breaking of a covalent bond is known as

Homolytic Fission

The fission of a covalent bond with equal

sharing of bonding electrons.

Free radicals are neutral but reactive species

having an unpaired electron and these can also

initiate a chemical reaction.

Heterolytic Fission

The fission of a covalent bond involving unequal sharing of bonding electrons.

carbonium ion or a carbocation

The ion which has a positive charge on the carbon atom

carbanion

ion with a negative charge on the carbon atom

Electrophiles

an electron deficient species and it may be positively charged or neutral.

Examples are H+ , AlCl3 , Br2 , Cl2 , Ag+ ,CH3+, BF3 etc.

Nucleophiles

negatively charged or electron rich neutral species.

Examples of nucleophiles are OH-, -NO2+

Substitution

involves the displacement of one atom or group in a molecule by another atom or group. Aliphatic compounds undergo nucleophilic substitution reactions.

Elimination

characterized by the removal of a small molecule from adjacent carbon atoms and the formation of a double bond.

Addition

Unsaturated hydrocarbons such as alkenes and

alkynes are extremely reactive towards a wide

variety of reagents. The carbon-carbon double

bond (-C=C-) of an alkene contains two types of

bonds. In alkynes, three carbon-carbon bonds.

Molecular Rearrangements

proceeds with a fundamental change in the

hydrocarbon skeleton of the molecule. During this

reaction, an atom or group migrates from one

position to another.