Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Chemistry Edexcel A Level > Topic 18 Organic III > Flashcards

Topic 18 Organic III Flashcards

(65 cards)

Start Studying
1
Q

What did Kekule suggest the benzene structure to look like?

A

Cyclohexa1,3,5-triene

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

How was Kekule’s benzene structure suggestion proved/disproved?

A

Supported by
- very sooty after combusting (due to low C:H ratio)
Disproved by
- bromine water does not react, so no C=C bonds
- regular bond lengths
- enthalpy of hydration values

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

What are chemical evidences for the structure of benzene?

A
  1. Bromine water doesn’t decolourise, so no C=C present
  2. X-ray crystallography, equal bond lengths so same bonds between each C
  3. Enthalpy of hydration data - much lower than expected
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What do you see with HCl / HBr/ HI?

A

WHITE MISTY FUMES

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

benzene + O2 →
(complete)

A

6CO2 + 3H2O

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

benzene + O2 →
(incomplete)

A

3H2O + 6C
or
6CO + 3H2O
depending on Q - always 2 products

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

benzene + bromine with catalyst →

A

catalyst FeBr3
bromobenzene + HBr

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

what are the 4 stages of electrophilic substitution?

A
  1. formation of electrophile
  2. attack of electrophile
  3. reformation of π system
  4. reformation of catalyst
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

benzene + conc nitric acid + catalyst →

A

catalyst conc H2SO4
nitrobenzene + H2O

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

benzene + halogenoalkanes + catalyst →
What conditions?

A

catalyst AlCl3
alkyl benzene (or phenyl alkane) + HX
in reflux

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

benzene + acyl chloride + catalyst →

A

catalyst AlCl3
phenyl ketone + HCl

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

what are methyl benzene’s properties?

A

alkyl group is e- pushing
so pushes e- density into pi system
so more easily attacked by electrophiles

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

what’s another name for methyl benzene?

A

toluene

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

is benzene or methyl benzene more reactive?

A

methyl benzene
has lower activation energy
e- pushing, higher e- density in ring, so more susceptible to attack by electrophiles

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

what is a phenol?

A

benzene with OH attached to one of the C

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

phenol + bromine/bromine water →
What are the products and what is observed?

A

2,4,6-tribromophenol + 3HBr
white ppt
no heating, no catalyst

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

phenol + dil HNO3 →

A

mixture of 2-nitrophenol and 4-nitrophenol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

pH of phenol?

A

weak acid
reacts like alcohol
but more stable
due to resonance stability (feeing e- into delocalised pi system)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is the amine functional group?

A

N with lone pair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the amide functional group?

A

-C=O
|
N

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How to identify amino acids?

A

Most have chiral C
Has amino (NH2) group
and COOH group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Butyl amine + water →

A

Butyl ammonium
+ OH-
OH- released makes alkaline solution!!!
as N in Butyl amine has lone pair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

amine + excess acid (like HCl) →

A

salt (+ water sometimes, not necessarily be in eq)
R-NH3+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

1° amine + acyl chloride →

A

2° amide + HCl

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
butyl amine + bromomethane → if excess amine
single substitution methyl butylamine + HBr / butylammonium bromide
26
butyl amine + bromomethane → if excess halogenoalkane
multiple substitutions ASK RJJ
27
butyl amine + copper(II) ions
form complex ions has central metal ion with its covalently bonded **ligand** Amines have a lone pair so can make dative covalent bonds [Cu(H₂O)₆]²⁺ + Butyl amine -> [Cu(OH)2(H2O)4]
28
What are the techniques to prepare and purify organic compounds?
1 reflux 2 purify by washing 3 solvent extraction 4 **recrystallisation** 5 drying 6 distillation 7 bp / mp determination
29
Why is suction filtration good to purify organic solids?
Quicker and more dry than using just filter paper
30
Describe the recrystallisation process to obtain a pure dry sample of organic compounds (like paracetamol)? (5 marks)
1. Dissovle in MINIMUM HOT solvent 2. filter hot (in steam bath) AND allow cool 3. Filter AND wash with minimum cold solvent 4. dry in warm oven
31
Why is heated funnel and filter paper used in recrystallisation?
Prevent product from crystallising to maximise yield
32
How to remove water?
Anhydrous sodium/magnesium sulphate (very fine powder)(so when water absorbed, will stay solids, won’t dissolve)
33
Why is the thermometer bulb located at the sidearm in distillation?
It must read the temp of substance, gas collected
34
What does steam distillation do?
Heating lots of water into steam To change the environment so reaction mixture agitated by steam **lowers bp** of organic substance that’s likely to decompose
35
How does steam distillation lower bp of organic substance?
Reaction mixture agitated by steam Changing the atmosphere and IMFs of environment ( from London to H bonds in water) To its lowest decomposition point
36
How to use melting temperature determination?
Use mp apparatus To measure the temp of solid If pure substance, all melt at one temp If impure, will melt at a range of temps
37
Is primary or tertiary amine more basic?
Tertiary Because it is more e- pushing Since it has most alkyl groups
38
How to make primary amines from Halogenoalkane?
NH3 + R-X -> R-NH2 + HX or NH4X (Excess NH3, sealed tube)
39
How to convert nitriles to primary amine?
Add reducing agent LiAlH4 in dry ether // H2 + Ni catalyst
40
Benzene + HNO3 -> In what conditions, makes what? Then + [H] makes what?
H2SO4 heat under reflux 50C Makes nitrobenzene + 6[H] reflux in conc HCl + Sn Make phenylamine (or aminobenzene) + water
41
How to make amides from acyl chloride?
Acyl chloride + 1° / 2° amine / ammonia -> HCl + amide
42
What reaction is the formation of polyamides?
Condensation
43
How to polyamide reaction?
H and Cl react like H and OH in esters
44
Amino acid with carboxylate on the side refluxed in excess acid will make...
Protonated Amino acid on amino group But N has 3 H bonded to it, + charge COOH on C2
45
Why is Grignard reagents good?
Lengthens carbon chain - not just by one, can be by many
46
Carbonyls + HCN →
OH and CN added to the carbon that had =O hydroxynitrile produced
47
How to make Grignard reagent?
Haloalkane + Mg reflux in dry ether
48
Why must making Grignard reagent be in dry ether?
Grignard will react with water and make Alkane + MgXOH which we dont want
49
What is solid CO2?
Dry ice
50
Grignard + CO2 (s) → What conditions needed?
follow by dil H+ (like HCl) Carboxylic acid (with C added from CO2) R-Mg-X + CO2 -> R-COOH + MgXX
51
Grignard + carbonyl →
Alcohol + MgXX follow by dil H+ C forms bond with R on Grignare, =O broken, O- gains H from H+, keeps original H on C. =O into -OH
52
What is the condition of electrophilic substitution involving benzene?
reflux
53
Why does bromine react more readily w phenol than benzene?
the hydroxyl (-OH) group in phenol increases the electron density in the benzene ring, making it more susceptible to electrophilic attack by bromine
54
Grignard + water ->
Alkane
55
How to make aminobenzene from nitrobenzene?
+ Sn + Conc HCl Then + NaOH
56
How to work out if it is a electrophilic or nucleophilic, substitution or addition?
Electrophilic when mechanism arrows point away from the organic molecule. When attacked by nucleophile, electrons and arrows point towards the organic molecule. Addition when Alkene C=C is broken to form C-C
57
What is the effect of a hydroxy group on a benzene ring in comparison to the ring without? (3 marks)
- **lone pair from the oxygen** **delocalises** , incorporates into benzene ring - electron density in phenol is greater than benzene - increases electron density in the ring AND will OVERLAP with the delocalised ring of electrons (overlap with pi orbital) - increasing reactivity toward electrophile such as bromine
58
Give the steps to show how 2,4-DNPH could be used to distinguish between phenylethanone and phenylethanal. (4 marks)
- bright yellow ppt formed - filter then recrystallise ppt - use melting point apparatus to find melting point of each - compare from use of database
59
What properties do Grignard reagent have? (2 marks)
Nucleophile Reducing agent
60
What are properties of amino acids?
Can act as buffers V soluble in water High MP Solid at RTP
61
How to hydrolyse proteins?
Break peptide bonds By refluxing under acidic and alkaline conditions Eg reflux in conc HCl for several hours
62
How to hydrolyse polyamides? What are the products?
Acid hydrolysis or alkali hydrolysis Acid: COOH-R-COOH & NH3^+ - R - NH3^+ Alkali: -OOC - R - COO - & NH2-R-NH2
63
Compare basicity between phenylamine and butylamine. (3 marks)
- both are basic as they have lone pair of e-s on non atom, which accepts proton - In phenylamine, lone pair of e-s of N becomes incorporated with delocalised ring of e-so so is less able to accept a proton, so weaker base - alkyl group is e- releasing, so atom more able to accept a proton, hence stronger base
64
Explain why amino acids such as glycine are crystalline solids are RTP. (2 marks)
Amino acids exist as ZWITTERIONS Ionic bonds form between zwitterions
65
When I see amino acid, think…
ZWITTERIONS Molecule having a positively and negatively charged group

Chemistry Edexcel A Level (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions