Module 2 Chapter 13/14

Question 1

What reagent and condition is needed for an alkene to react to form alcohol

Answer 1

Acid catalyst (H3Po4) and steam

Question 2

What is meant by the term structural isomer

Answer 2

Same molecular formula but different structural formula

Question 3

Suggest why an alkene is less soluble in water than an alcohol

Answer 3

Alkenes do not contain OH groups therefore do not form hydrogen bonds with water

Question 4

What is the mechanism when an alkene reacts with a bromine molecule to produce 1,2,3 tribromopropane

Answer 4

Electrophilic addition

Question 5

State what reagent and condition is needed for alkene to form 1-bromopropane

Answer 5

Hydrogen and nickel catalyst

Question 6

Radical substitution produces a mixture of organic products.
Suggest 2 reasons why

Answer 6

It produces different termination products

Substitution at different positions along the chain

Question 7

What is the general formula for alkyl groups

Answer 7

CnH2n+1

Question 8

Iodine monobromide, I-Br, is a polar molecule.
Heterolytic fission of the I-Br bond forms an electrophile.
State the meaning of the term electrophile and suggest the formula of the electrophile formed from IBr

Answer 8

Electrophile is electron pair acceptor

I+

Question 9

What does a curly arrow represent in a reaction mechanism

Answer 9

Movement of a pair of electrons

Question 10

Cyclopentene can be prepared from cyclopentanol .

What type of reaction is this

Answer 10

Elimination reaction

Question 11

Describe the oxidation reactions of Butan-1-ol forming an aldehyde and a carboxylic acid

Answer 11

Butan-1-ol can be heated under distillation and the oxidising agent is Cr2O7 2- and the catalyst is an acid - H+.
This produces an aldehyde ; butanal - CH3CH2CH2CHO

Butan-1-ol can also be heated under reflux and the oxidising agent is Cr2O7 2- and the acid catalyst is H+. This produces a carboxylic acid ; but anoxic acid. CH3CH2CH2COOH
this is done by distillation

Question 12

Bromocyclohexane —> E —> cyclohexene

What compound is E and what reagent and conditions is needed

Answer 12

Cyclohexane-1-ol

Acid catalyst and heat

Question 13

Why is butan-2-ol classified as a secondary alcohol

Answer 13

Butan-2-ol ha 2 R groups ; Ch3 and C2H5

Question 14

Give one reason why a Bunsen burner and a beaker is not suitable apparatus for oxidising butan-2-ol

Answer 14

Butan-2-ol is flammable and will boil away so you need to head under reflux using a condenser and a pear shaped flask

Question 15

At room temperature and pressure, the first four members of the alkanes are all gases but the first four alcohols are all liquids. Explain this difference in terms of intermolecular forces.

Answer 15

Alkanes only contain hydrogen and carbon therefore they only have london forces. Alcohols contain OH bonds therefore hydrogen bonds can be made.
Hydrogen bonds are stronger than london forces.

Question 16

2-methylpropan-1-ol = 108°
Butan-1-ol = 117°
Explain why the boiling points are different

Answer 16

2-methylpropan-1-ol has less surface contact. It has fewer london forces compared to butan-1-ol. So less energy is required to break the london forces.

Question 17

Describe a simple test a student can carry out to confirm the presence of an alkene

Answer 17

Bromine water should turn from brown to colourless ; decolorisation

Question 18

What observations are made during oxidation of alcohols

Answer 18

Should turn orange to green

Question 19

Suggest one advantage of adding cyclohexane to hexane in petrol

Answer 19

Cyclohexane will burn more efficiently

Question 20

Explain what is meant by the term stereoisomers

Answer 20

Same structural and molecular formula but different arrangement in space

Question 21

Explain how sodium hydrogen carbonate removes hydrogen chloride

Answer 21

Sodium hydrogen carbonate neutralises HCL

Question 22

Alkene to alkane what reagents and conditions do u need

Answer 22

Hydrogen and nickel catalyst

Question 23

Outline how a catalyst increases the rate of a chemical reaction

Answer 23

A catalyst speeds up the rate of reaction by lowering the activation energy so grater proportion of molecules exceed the activation energy

Question 24

Combustion of polymer produced HCL, which is a toxic gas.

Describe how hcl is removed from the waste gases produced

Answer 24

HCl is passed through alkali

Question 25

State one advantage of using polymers made from natural foods

Answer 25

Biodegradable

Question 26

What is the general formula for alkyl group

Answer 26

CnH2n+1

Question 27

Waste polymers are processed to save resources. E.g. by recycling
Describe two other ways in which waste poly(propene) can be processed in a sustainable way

Answer 27

1. Combustion for energy production

2. Use as an organic feedstock

Question 28

Pent-1-ene does not show stereoisomerism

Explain why

Answer 28

One of the carbons of the C=C has 2 of the same groups attached

Question 29

Describe one difference between the sigma bond and the pi bond

Answer 29

Sigma bond is a head on overlap.

Pi bond is a sideways overlap

Question 30

State and explain the features of a hex-2-ene molecule that lead to E and Z isomers

Answer 30

Carbon-carbon double bond does not rotate

Each carbon atom of the double bond attached to 2 different groups

Question 31

State one advantage and disadvantage of using combustion as a method for the disposal of waste polymer 1-dichloro, ethane

Answer 31

advantage - energy production which produces electricity

disadvantage - contains Cl which produces HCl a toxic gas which can cause acid rain

Question 32

A student reacts pent-2-ene with bromine in the laboratory.

What does It form?

Answer 32

D - 2,3-dibromopentane