Basic O-Chem Concepts

Question 1

Why is carbon so special?

Answer 1

• Contains 4 electron in the outer shell, able to form 4 COVALENT BONDS!
• Single, double and triple bonds possible!

Question 2

What are saturated + unsaturated hydrocarbon?

Answer 2

1. Saturated: Single C-C bonds, only carbon and hydrogen
2. Unsat: Double C=C bonds!

Question 3

What is a Homologous Series?

Answer 3

• This is a series of hydrocarbonds with the same functional group, very similar chemical properties, and differs by CH2 per successive member!

Question 4

What are Aliphatic, Alicyclic and Aromatic Hydrocarbonds

Answer 4

1. Aliphatic = Carbon atoms, joined branched/unbranched, with NO BENZENE RING
2. Alicyclic = Carbon atoms joined in any ring-like structure (cyclo-….)
3. Aromatic = Carbon atoms bonded in a BENZENE RING, with alternating single/double bonds

Question 5

Main things to remember for Nomenclature?

Answer 5

1. Alphabetical listing for ALL ALKYL GROUPS
2. Number C=C bonds accroding to 1st carbon involved, e.g. but-2-ene

Question 6

What is Molecular, Empirical and General Formula of molecule?

Answer 6

1. Molecular = How many atoms are present
2. Empirical = Simplest form of molecule
3. General = uses “n” as a rule of molecule

Question 7

What is Displayed, Structural and Skeletal Formula of molecule?

Answer 7

1. Dislplayed = Shows all bonds present in molecule
2. Structural = Brocken into written, smaller sub-sections of displayed
3. Skeletal = uses pure lines to show bonds

Question 8

What is Structural Isomerism?

Answer 8

• Compounds with same molecular formula, but different structural formula!

Question 9

What is Homolyctic Fission?

Answer 9

• This is breaking of covalent bond, where ONE of BONDED e- going to each atom, forming FREE RADICALS!

Question 10

What is Heterolyctic Fission?

Answer 10

• This is breaking of covalent bond, forming CATION and ANION!

Question 11

Define Electrophile!

Answer 11

• Atom/atom group attracing to a region of HIGH e- DENSITY, normally +ve
• basically an electron acceptor

Question 12

Define Nucleophile!

Answer 12

• e- PAIR DONOR!
• Attracs to positive-charged regions

Question 13

Define Free Radical!

Answer 13

• Species with a SINGLE UNPAIRED e-!
• VERY unstable = VERY reactive indeed

Question 14

What are curly arrows for?

Answer 14

• Double head = e- pair transfer!
• Half single head = SINGLE e- transfer!

Question 15

Define Addition, Subsitution and Elimination Reactions!

Answer 15

• Addition = 2 reactants react to form one single product
• Sub = Atoms/atom group replaced by different atoms
• Elim = Removal of a smaller molecule, from an overall main, larger molecule