organic chem🛢🛢

Question 1

colour change when alcohol is oxidised with potassium dichromate

Answer 1

orange to green

Question 2

what is homologous series

Answer 2

• series of compounds with same functional group

- each successive member differs by CH2

Question 3

everyday use of ir spec

Answer 3

• monitor air pollution

- breathalyser

Question 4

what is functional group

Answer 4

group of atoms that give compound its characteristic set of reactions

Question 5

equation for incomplete combustion of methanol

Answer 5

CH3OH + O2 —> CO + 2H2O

Question 6

reagent to improve atom economy of alcohol to bromoalkane

Answer 6

NaBr

Question 7

would iodobutane or bromobutane react faster with hydroxide ions and why

Answer 7

• iodobutane

- C-I bonds are weaker than C-Br

Question 8

greenhouse effect is dependent on two factors

Answer 8

• absorption of IR radiation

- abundance in atmosphere

Question 9

which haloalkane is unreactive

Answer 9

fluoroalkane

Question 10

biodegradable alternative to CFCs

Answer 10

HFCs

Question 11

why are CFCs used as aerosols

Answer 11

• non toxic
• non flammable
• easily vaporised

Question 12

why does CF2Cl2 not hydrolyse in water

Answer 12

C-F need a lot of energy to break

Question 13

how do CFCs deplete ozone

Answer 13

Cl catalyses decomposition of ozone
O3+Cl2–> ClO + O2
ClO+ O3–> Cl+ 2O2

Question 14

why is ozone depletion a concern

Answer 14

more UV rays reach Earths surface so higher risk of skin cancer

Question 15

what is homolytic fission

Answer 15

-one electron from bond goes to each atom

Question 16

why can compounds have ez isomers

Answer 16

• restricted rotation around carbon double bond

- each carbon atom of double bond is bonded to different groups

Question 17

why can hydroxide ions act as nucleophile

Answer 17

lone pair can be donated

Question 18

why would petroleum industry produce cyclohexane

Answer 18

more efficient combustion

Question 19

unsaturated

Answer 19

contains double carbon bonds

Question 20

flask used in reflux

Answer 20

round bottom flask

Question 21

how to separate fluids of different densities

Answer 21

• use separating funnel to separate organic and aqueous layers
• collect lower organic layer as it has greater density
• drying with anhydrous salt
• redistillation

Question 22

test for ammonium

Answer 22

warm solution with NaOH

ammonia should be produced, test with moist indicator paper which will go blue