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Question 1

Halogenoalkanes react with water to produce…?

Answer 1

an alcohol

Question 2

What is the reactivity of halogenoalkanes?

Answer 2

Increases down the group

Question 3

Explain the experiment to determine the rate of halogenoalkanes?

Answer 3

Place chloroalkane,
bromoalkane and
iodoalkane into 3 test
tubes. Add silver nitrate
solution and ethanol
(solvent) to each tube. Iodide forms a yellow precipitate first
Ag^+ + I- produces AgI

Then bromine (cream), lastly chlorine (white)

This is because the halide ion gets larger down
the group and this leads to a
weaker bond.

Question 4

Do halogenoalkanes have a polar bond?

Answer 4

yes

Question 5

How do halogenoalkanes react with hydroxide ions and what are the conditions?

Answer 5

Nucleophilic substitution
- Under reflux
- warm aqueous sodium hydroxide

Question 6

What is the reaction with cyanide ions and the conditions?

Answer 6

Produce nitriles
- Under reflux
- warm ethanolic potassium cyanide

Question 7

What is the reaction with ammonia and the conditions?

Answer 7

• heat with ethanolic ammonia
• must have excess ammonia

Question 8

How do you make iodoalkanes?

Answer 8

react iodine with PI3 (phosphorous triiodide)
- made in - situ under reflux with the alchohol red phosphorous

Question 9

How can alkenes be made from alcohols?

Answer 9

Dehydration
- involves use of an acid catalyst either sulfuric acid of phosphorous acid

Question 10

What are the products of the dehydration of non primary alcohols?

Answer 10

• 3 different types of alkenes
  e.g
• but-1-ene
• E but-2-ene
  -Z but-2-ene

Question 11

What does heterolytic fission form?

Answer 11

form 2 different ions

Question 12

What does homolytic fission form?

Answer 12

form 2 uncharged radicals

Question 13

What is the mechanism when reacting an alkane and a halogen?

Answer 13

free radical sub

Question 14

What are the products of thermal cracking?

Answer 14

alkenes

Question 15

What is catalytic cracking and the conditions?

Answer 15

• high tmperature 450 degrees
• slight pressure
• a zeolite catalyst
• products are aromatic hydrocarbons useful in fuels for vehicles.

Question 16

How are alkanes reformed into cycloalkanes and aromatic molecules?

Answer 16

Reforming
- cyclic and branched alkanes can be made from straight chain alkanes
- A platinum catalyst

Question 17

What are the producst of incomplete combustion?

Answer 17

carbon monoxide and carbon

Question 18

What are catalytic converters?

Answer 18

• are mainly found in vehicles to reduce harmful pollutant entering the atmosphere.
• ## produces water vapour, nitrogen and carbon dioxide

Question 19

What are sigma and Pi bonds?
Which are stronger/ weaker?

Answer 19

• SIgma
  2 s orbitals overlap
• align horizontally
• strong electrostatic attraction due to high electron denisty

Pi
- parallel overlap
- weaker as the electron density is spread out above and below the nuclei = low bond enthalpy

Question 20

When do we use E/Z isomerism?

Answer 20

when you need to work out which compound has higher/ lower priority

Question 21

What is produced in the hydration of alkenes?
- conditions

Answer 21

• alcohol is produced
• make ethene by
  phosphoric acid catalyst and steam