Lecture 11 + 12 - Organic Chemistry

Question 1

Give 4 important organic molecules in the body

Answer 1

1. aspirin -painkiller with carboxylic, ester and aryl functional groups
2. cis-11-retinal - vision dependance, contains alkene and aldehyde functional groups
3. adrenaline - secreted in response to stress contains alcohol, amine, and phenol functional groups
4. sodium lauryl sulphate - soap - reaction between fats and oils containing ester functional groups

Question 2

Describe unsaturated hydrocarbons

Answer 2

alkenes and alkynes contain at least one double or triple bond

Question 3

what is the non systematic name for 2-methylpropane

Answer 3

isobutane

Question 4

what is the non systematic name for 2,2-dimethylpropane

Answer 4

Neo-pentane

Question 5

what dies the Neo prefix mean?

Answer 5

an alkane that contains (CH3)3C and no other branches

Question 6

what is an alicylic compound?

Answer 6

compound containing a ring of saturated carbon atoms

Question 7

what is an aromatic compound?

Answer 7

a ring where all atoms are unsaturated

Question 8

what is a heterocyclic compound?

Answer 8

a ring containing at least one other compound e.g. N,S,O

Question 9

what is an ether

Answer 9

R-O-R functional group is alkoxy

Question 10

what is a thiol?

Answer 10

R-SH

Question 11

what is a sulphide?

Answer 11

R-S-R

Question 12

what is an amide?

Answer 12

chain with double bonded oxygen and NR/H2 group

Question 13

what is the order of principle functional groups?

Answer 13

carboxylic acid
ester 
acid halide 
amides
nitriles
aldehyde 
ketone
alcohol
amine
double bond 
triple bond 
halogen 
nitro

Question 14

what its a homologous series?

Answer 14

a group of organic compounds with similar chemical properties in which members contain the same functional group but differ by length of carbon chain

Question 15

what is a hybrid atomic orbital?

Answer 15

combination of atomic orbitals from the same atom

Question 16

what is a molecular orbital?

Answer 16

combination of atomic or hybrid atomic orbitals from different atoms

Question 17

what is LCAO?

Answer 17

linear combination of atomic orbitals - orbitals combine to form hybrid atomic orbitals and molecular orbitals

Question 18

what is sp3 hybridisation?

Answer 18

• all four atomic orbitals combine to give the same number of new hybrid atomic orbitals
• used for bonding in saturated compounds
• one sigma bond
• saturated compounds

Question 19

what is sp2 hybridisation?

Answer 19

• the s and two p orbitals combine to give three new hybrid atomic orbitals
• used for bonding in alkenes, carbonyls and aromatic rings
• one sigma bond and one pi bond
• alkenes, carbonyls and aromatics

Question 20

what is sp hybridisation?

Answer 20

• the s and 1 p orbital combine to give two new hybrid atomic orbitals
• used for bonding in alkynes and nitriles
• one sigma bond and two pi bonds
• alkynes and nitriles

Question 21

what are the properties of hybrid orbitals?

Answer 21

• hold electrons close to the nucleus
• bond becomes shorter therefore stronger
• more directional bond so more effective bonding interactions
• the more s character in an orbital the lower the energy therefore increased stability of an electron in that orbital

Question 22

Describe sigma bonds

Answer 22

formed by direct overlap of orbitals, electron density is along the line of the bond

Question 23

Describe a pi bond

Answer 23

formed by parallel overlap of p orbitals, electron density is above and below the plane of the bond
-higher energy than sigma bond therefore weaker

Question 24

Describe bonding in benzene

Answer 24

sp2 hybridisation as the electrons are delocalised in the ring and pi electrons are delocalised above and below the plane