Organic Chemistry 6

Question 1

formula for benzene

Answer 1

C6H6

Question 2

how are the 6 carbons in benzene arranged?

Answer 2

in a ring structure

Question 3

how many electrons does each carbon have in its outermost shell

Answer 3

4

Question 4

what happens to the 3 of the 4 electrons in carbon’s outer shell

Answer 4

form sigma bonds

Question 5

3 sigma bonds formed by carbon’s electrons

Answer 5

2 formed between each carbon atom

1 between carbon and hydrogen

Question 6

what shape do these electrons give benzene

Answer 6

planar hexagonal ring

Question 7

where is the 1 electron that is left

Answer 7

in a p orbital

Question 8

describe what happens to the p orbitals

Answer 8

the lobes of these p orbitals fuse to form a single ring of charge above and below the sigma bond skeleton. these are pi bonds. electrons can move around - delocalised

Question 9

what does the delocalisation of electrons cause

Answer 9

causes bonds in benzene to be similar and makes the molecule unexpectedly stable

Question 10

what are the bonds in benzene

Answer 10

not single and not double, but an intermediate between the two

Question 11

which type of reaction would benzene typically undergo?

Answer 11

substitution reactions

Question 12

what would one might expect to be benzene’s usual reaction type and why

Answer 12

addition reactions as it is unsaturated

Question 13

is benzene a polar or non-polar molecule and why?

Answer 13

non-polar as the centres of positivity coincide

Question 14

is benzene soluble in water and why

Answer 14

no as it is non-polar and does not form hydrogen bonds with water

Question 15

what did benzene used to be used for and why not anymore

Answer 15

as an organic solvent but no longer as it is carcinogenic

Question 16

what is now used in benzene’s place as an organic solvent

Answer 16

methylbenzene

Question 17

some aromatic pharmaceuticals

Answer 17

aspirin, morphine, paracetamol, penecillin

Question 18

aromatic dye

Answer 18

napthalene

Question 19

some aromatic narcotics

Answer 19

heroin and cocaine

Question 20

aromatic insecticide

Answer 20

DDT

Question 21

aromatic disinfectant

Answer 21

TCP

Question 22

aromatic material

Answer 22

terylene is a type of polyester

Question 23

aromatic indicator

Answer 23

phenolphthalein

Question 24

some aromatic fragrant oils

Answer 24

menthol and clove oil

Question 25

EXTRACTION OF CLOVE OIL | main constituent of clove oil

Answer 25

eugenol

Question 26

EXTRACTION OF CLOVE OIL | principle of steam distillation

Answer 26

when two immiscible liquids are together, their boiling point is lower than either of the two pure compounds alone

Question 27

EXTRACTION OF CLOVE OIL | 2 immiscible liquids

Answer 27

oil and water

Question 28

EXTRACTION OF CLOVE OIL | if you did not mix with water

Answer 28

would have to bring cloves up to the oil's boiling point and would char the clove and would become impossible to extract the oil

Question 29

eugenol | top

Answer 29

OH

Question 30

eugenol | first right C

Answer 30

OCH3

Question 31

eugenol bottom

Answer 31

C-H C-H H-C-H

Question 32

EXTRACTION OF CLOVE OIL if oil doesn't form a separate layer solvent extraction

Answer 32

droplet dispersed - emulsion organic solvent dissolves oil and then separated from water using separating funnel organic solvent evaporates off

Question 33

EXTRACTION OF CLOVE OIL | safety precaution

Answer 33

wear gloves as oil can burn the skin

Question 34

EXTRACTION OF CLOVE OIL | first step

Answer 34

add water to steam generator

Question 35

EXTRACTION OF CLOVE OIL | explain the safety tube

Answer 35

placed in the steam generator, bottom should be well below level of water. water topped up regularly. relieves pressure, avoids build up of steam and explosion

Question 36

EXTRACTION OF CLOVE OIL | where do you put the cloves

Answer 36

in the pear shaped flask with some water

Question 37

EXTRACTION OF CLOVE OIL | cloves are in

Answer 37

bunsen burner turned on and steam allowed to pass through for 40 minutes

Question 38

EXTRACTION OF CLOVE OIL | what happens to the clove oil emulsion

Answer 38

passed through the condenser to the receiver (separating funnel)

Question 39

EXTRACTION OF CLOVE OIL | describe the emulsion

Answer 39

milky colour

Question 40

EXTRACTION OF CLOVE OIL | what happens to emulsion

Answer 40

allowed to cool

Question 41

EXTRACTION OF CLOVE OIL | what is added to emulsion

Answer 41

organic solvent e.g.cyclohexane added and contents of separating funnel shaken vigorously

Question 42

EXTRACTION OF CLOVE OIL | before separating emulsion

Answer 42

invert the funnel and tap to release pressure

Question 43

EXTRACTION OF CLOVE OIL | how do you extract

Answer 43

draw off the clear aqueous lower layer into a beaker labelled aqueous and repeat the process many times with the organic layer

Question 44

EXTRACTION OF CLOVE OIL | why do you repeat many times

Answer 44

to maximise the yield of oil collected

Question 45

EXTRACTION OF CLOVE OIL | where do you then place the organic layer

Answer 45

in a beaker, it may contain some water

Question 46

EXTRACTION OF CLOVE OIL | what do you add to the organic layer in the beaker and how much? what happens?

Answer 46

add enough anhydrous sodium sulfate so that it no longer clumps together it should appear to settle as a dry powder when all of the water has been removed from the clove oil

Question 47

EXTRACTION OF CLOVE OIL | after adding anhydrous sodium sulfate

Answer 47

swirl flask and filter to remove drying agent, rinse with cyclohexane to maximise yield of oil

Question 48

EXTRACTION OF CLOVE OIL | last step

Answer 48

the cyclohexane solvent was allowed to evaporate off from the filtrate in a warm place or desiccator. This leaves the clove oil behind, measure its volume.