Topic 6 Flashcards

1
Q

What type of reaction is where alcohols react with concentrated phosphoric acid to form alkenes?

A

ELIMINATION

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is meant by stereoisomers?

A
  • compounds with same structural formula

Where the atoms have a different displayed formula

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

CH3CH2CH2CH2OH reacts with the oxidising agent potassium dichromate(VI) in dilute sulfuric acid.
Two organic products can be formed, depending on the conditions.
Write a balanced equation for the formation of one of these products, giving its name and the condition required to achieve this product in high yield.
Use [O] in the equation to represent each oxygen atom from the oxidising agent.
Equation

Name ……………………………………………………………………………………………………………………………
Condition ………………………………………………………………………………………………………………………

A

CH3CH2CH2CH2OH + 2[O] -> CH3CH2CH2COOH+ H2O

BUTANOIC ACID

HEAT UNDER REFLUX

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

One reason why the yield calculated is less than 100%

A
  • side reactions
  • incomplete
  • transfer losses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Deduce a chemical test for a C=C bond

A

Bromine water

Orange/ brown goes colourless

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Devise a procedure to obtain a pure dry sample of cyclohexane from the distillate

A
  • separate cyclohexane from water using SEPARATING FUNNEL
  • remove AQUEOUS layer as it has a higher density
  • use a drying agent (metal Sulfates)
  • separate cyclohexene from drying agent
  • redistil product (by FILTRATION OR DECANTATION)

-collect after boiling at temp between 80-86

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Using apparatus for distillation instead of reflux is not an efficient way to produce ethanoic acid from ethanol. Explain why.

A

Ethanol would be OXIDISED to ethanal

Ethanal has a LOW BP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Give a reason for the addition of ethanol to each test tube (1)

A

Increases solubility or dissolves the halogenoalkane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Give a reason why the test tubes were left in the water bath for 5 mins before adding the halogenoalkanes (1)

A

Allow solutions to equillbrate and reach required temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Explain why halide ions are present in the mixture containing a halogenoalkane which only has covalent bonds (2)

A

(Halogenoalkane) hydrolysed by water

C-Hal bond breaks (heterolytically producing ions)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Write the ionic equation with state symbols for the reaction involving silver nitrate in test tube X (1-chlorobutane)

A

Ag+ (aq) + Cl- (aq) -> AgCl (s)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which of the following DOES NOT act as a nucleophile

  • HBr
  • H2O
  • NH3
  • CN-
A

HBr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what type of reaction occurs when propene reacts with HCl?

A

electrophilic addition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Q: NAME the reagents used in reaction 1

chloropropane can react to form organic products as shown in the reaction scheme:

CH3 CH CH2 Reaction 1

CH3 CH2 CH2 C N
Reaction 2

CH3CH2 CH2 Cl Reaction 3

concentrated ammonia solution heated in a sealed tube

CH3 CH2 CH2 NH2

A

Reagent: NaOH/ KOH
condition: ethanol and heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

ii) Identify a suitable reagent for Reaction 2 and include a reason why this is a particularly useful type of reaction in organic chemistry. (2)

chloropropane can react to form organic products as shown in the reaction scheme:

CH3 CH CH2 Reaction 1
CH3 CH2 CH2 C N Reaction 2
CH3 CH2 CH2 Cl Reaction 3
concentrated ammonia solution heated in a sealed tube=
CH3 CH2 CH2 NH2

A

KCN/NaCN /potassium cyanide / sodium cyanide (1)

Reason:
increases the number of carbon atoms in the carbon chain/ length of carbon chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Explain why, in reaction 3, the reagents are HEATED in a sealed container

chloropropane can react to form organic products as shown in the reaction scheme:

CH3 CH CH2 Reaction 1
CH3 CH2 CH2 CN Reaction 2
CH3 CH2 CH2 Cl Reaction 3
concentrated ammonia solution heated in a sealed tube
CH3 CH2 CH2 NH2

A

heating increases rate (of reaction) (1)

no sealed tube would result in loss of ammonia (gas)/ reactants / gas

17
Q

Write the structural formula of the product that will be formed if 1-chloropropane is refluxed with aqueous potassium hydroxide solution

A

CH3 CH2 CH2 OH

18
Q

explain why isomers of hexane have lower boiling temps and so are found in the petrol fraction (3)

A

isomers have branched chains

branched chains have lower SA

Intermolecular forces are weaker

19
Q

explain the 2 major reasons for cracking hydrocarbons (3)

A

SHORTER chain alkanes AND alkenes formed

alkenes used to make polymers/plastics

shorter chain alkanes are more in demand

20
Q

describe 2 charactersitics of the homologous series

A

same general formula

same functional group

21
Q

what is meant by structural isomer?

A

same molecular formula
different displayed formula

22
Q

state the purpose of adding ethanol to test tubes

A

to dissolve BOTH the laogenoalkane and water

23
Q

give one reason why the test tubes are placed in the same beaker of hot water

A

same temperature

24
Q

give one reason why the test tubes were shaken after the addition of aq silver nitrate

A

ensure reactants are mixed thoroughly

25
state how the halogen atom present in each halogenoalkane can be identified from observations in the experiment
CL- white Br - cream I - yellow
26
identify further reagents that can be added to confirm the identity of the halogen atom present in each halogenoalkane (2)
dilute AND conc ammonia solution silver chloride, silver bromide and silver iodide
27