HYDROCARBONS

Question 1

Organic compound

Answer 1

Carbon based compound
Always contain carbon and hydrogen atoms ( sometimes also other nonmetals: oxygen, sulfur, nitrogen,
phosphorus, or halogens such as iodine)

• Covalent bonds
• Low melting, boiling points
• Can undergo combustion

Question 2

Why a carbon based life?

Answer 2

C has four valence electrons:

• can form very stable C-C, C-H single bonds
• can form very stable double bonds
• C can form chains of infinite length
• C can achieve several oxidation states

Question 3

Methane CH4

Answer 3

Simplest organic molecule

C is hybridized sp3

Question 4

Hydrocarbons

Answer 4

• Simplest organic molecules
• Composed of carbon and hydrogen (Cx Hy)
• Can be saturated or unsaturated
• Apolar, do not mix with water

Question 5

Unsaturated C

Saturated C

Answer 5

only single C-C bonds: saturated

double C bonds: unsaturated

Question 6

Alkanes

Answer 6

Saturated CnH2n+2
first four:
- CH4 methane 
-C2H6 ethane 
-C3H8 propane 
-C4H10 butane 

The rotation about the C-C single bond is unrestricted ( three dimensional structure is fundamental to their chemical structure)

Question 7

Structural isomers

Answer 7

Two structures that represent the same molecules but have different arrangements of atoms

Question 8

Alkanes with substituents

Answer 8

If an alkane contains four or more carbon atoms, the atoms can be arranged so that a side group called a branch or substituent is attached to a carbon chain

Question 9

Cycloalkanes

Answer 9

cyclic or ring structures formed by hydrocarbons

Cyclopropane C3H6 is the simplest cycloalkane

Question 10

Alkyl group

Answer 10

A carbon branch ( an alkane that is missing one hydrogen)
ex.
CH3- methyl
CH3-CH2- ethyl

Question 11

Haloalkane

Answer 11

An alkane that has an halogen as substituent

Question 12

Unsaturated hydrocarbons

Answer 12

Alkenes: double bond
Alkynes: triple bond
ex.
Ethane, Ethene, Ethyne

Question 13

Cis-Trans isomers

Answer 13

In any alkene, the double bond is rigid ( no rotation), so the atoms or group are attached to one side or the other of the carbons in the double bond: cis-trans isomers.

cis: same side
trans: opposite sides

Question 14

Addition reactions in Alkenes

Answer 14

• Hydrogenation : H atoms add to each of the carbon atoms in a double bond ( product: Alkane)
• Hydration: an alkene reacts with water ( product: alcohol, catalyst: strong acid)
• Polymerization: addition of alkenes

Question 15

Markovnikov’s rule

Answer 15

When water adds to an asymmetrical double bond, the -H attaches to the carbon that has the greater number of H atoms and the -OH adds to the other carbon atom

Question 16

Aromatic compounds

Answer 16

Family of benzene

• CH3: toluene
• NH2: amiline
• OH: phenol

Question 17

Benzene

Answer 17

Hydrocarbon isolated by Faraday.
Consists of a ring of 6 carbon atoms with one hydrogen attached to each
(-C6H6 as a substituent: phenyl group)

Question 18

Prefixes to show the position of two substituents in an aromatic compound

Answer 18

• ortho 1, 2
• meta 1, 3
• para 1, 4