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Chemistry IAL EDEXCEL A-Level > Unit 4 > Flashcards

Unit 4 Flashcards

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1
Q

Acyl chlorides + water form?

A

Carboxylic acid + HCl gas (misty fumes)

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2
Q

Acyl chlorides + alcohol ->

A

Ester + HCl gas

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3
Q

Acyl chlorides + concentrated ammonia

A

Amide (-CONH2) + HCl

Further reaction to NH4Cl

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4
Q

Acyl chlorides + primary amine

A

N-substituted (RCONHR’) + HCl

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5
Q

Acyl chlorides + secondary amines ->

A

N,N-disubstituted amide (RCONH(R’)(R”) + HCl

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6
Q

Carboxylic acid + alcohol ->

A

In presence of acid catalyst (H2SO4) ester + H2O

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7
Q

Physical properties of esters

A

Low boiling point
Insoluble in water
Pleasant smells

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8
Q

Carboxylate salt (-COO-) COO with negative charge and a positive ion + H2SO4 ->

A

Carboxylic acid + metal salt

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9
Q

Types of reverse esterification

A

Acidic hydrolysis
Alkaline hydrolysis

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10
Q

How to do acidic hydrolysis in esters

A

Ester + warm water -> (acid catalyst H2SO4) carboxylic acid + alcohol
It is an equilibrium for and backward arrow needed

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11
Q

Alkaline hydrolysis in esters

A

Ester + NaOH -> carboxylate salt + alcohol
Complete reaction

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12
Q

What happens in condensation polymerisation

A

Diol (two OH groups at each end + dicarboxylic acid -> polyester + H2O

OH from COOH and H from OH (Acyl chlorides can be used to form HCL)

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13
Q

Stationary phase in chromatography

A

Liquid/ solid that does not move

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14
Q

Mobile phase in chromatography

A

Liquid moves through stationary phase transporting the substance tested

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15
Q

How do mobile and stationary allow chromatography to separate solvents

A

Chemicals more attracted to stationary phase and only slightly attracted to mobile phase will move less up the paper

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16
Q

Mobile phase in Paper chromatography

A

Solvent

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17
Q

Mobile phase in TLC chromatography

A

Solvent

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18
Q

Stationary phase in paper chromatography

A

Water trapped in the fibres of chromatography paper

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19
Q

Stationary phase in TLC chromatography

A

Sheet of glass coated with silica or alumina

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20
Q

Stationary phase of column chromatography

A

Alumina or silica soaked in solvent

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21
Q

Mobile face in solemn chromatography

A

The solvent added when pouring the mixture of top of the stationary phase

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22
Q

How is HPLC chromatography different to column chromatography

A

Solvent is forced through HPLC tube by high pressure

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23
Q

Stationary phase in HPLC chromatography

A

silica

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24
Q

What does a polar substance attract

A

Polar molecules

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25
Q

Mobile phase in HPLC chromatography

A

Hexane (non-polar)

26
Q

How are the different components measured in HPLC chromatography

A

By the absorption of UV light measured

27
Q

What state are the substances being measured in HPLC chromatography

A

Liquids

28
Q

What does Gas and HPLC measure

A

The retention time- time taken to detect the separation of components

29
Q

What is the mobile phase in gas chromatography

A

Inert gas

30
Q

What is the stationary phase in gas chromatography

A

The solid/liquid coated in the inside of tube

31
Q

How those the stationary phase affect the retention time

A

The weaker the attraction to stationary phase the shorter the retention time

32
Q

What does C13 NMR measure

A

Number of different chemical environments

(Peaks show different groups the carbon are connected to)

33
Q

Physical properties of Carboxylic acids

A

High boiling point which increase with Mr
Soluble but this decreases as chain length increases

34
Q

Oxidation reaction to make -COOH

A

Primary alcohol or aldehyde + acidified potassium dichromate with acid catalyst under reflux -> -COOH

35
Q

What does the hydrolysis of Nitriles produce

A

-COOH + another compound

36
Q

Types of hydrolysis of nitriles

A

Acidic hydrolysis
Alkaline hydrolysis

37
Q

Describe acidic hydrolysis of nitriles

A

1 step
Nitrile + dilute acid (H+) + H2O under reflux -> -COOH + NH4+

38
Q

Describe alkaline hydrolysis of nitriles

A

2 steps
Nitrile + NaOH + H2O under reflux -> -COO-Na+ + NH3

Further -COO-Na + H+ -> -COOH

39
Q

Reducing COOH

A

COOH + LiAlH4 in dry ether -> primary alcohol

40
Q

Halogenation of -COOH

A

-COOH + PCL5 in anhydrous conditions -> -RCOCl +POCl3 + HCl which results in misty fumes

41
Q

Esterification of -COOH

A

-COOH + -OH (acid catalyst) -> ester + water

42
Q

Neutralisation of -COOH

A

-COOH + OH- (strong alkali) -> carboxylate salt + water

43
Q

Reduction of aldehydes

A

Aldehydes + LiAlH4 in dry ether -> primary alcohol

44
Q

Oxidation of aldehydes

A

Aldehyde + acidified potassium dichromate + conc. acid under reflux -> -COOH

This will produce a colour change from orange to green

45
Q

Reduction of ketones

A

Ketone + LiAlH4 in dry ether -> secondary alcohol

46
Q

Oxidation of ketones

A

Ketones are not easily oxidised

47
Q

Test to distinguish from ketones and aldehydes

A

Fehlings solution: Deep blue to red ppt
Tollens reagent: Colourless solution to silver mirror

48
Q

What does the triodomethane (iodoform) test for

A

CH3CO group
Present in ethanal and methyl ketones

49
Q

Iodoform test equation

A

Methyl ketone + iodoform in alkaline sol. -> CHI3 (pale yellow ppt)

50
Q

Conditions and product of nucleophilic addition of Carbonyls + HCN

A

Happens in alkaline solution containing KCN

Makes hydroxynitriles

51
Q

What is 2,4-DNPH used for

A

It is a test which through nucleophilic addition forms an orange ppt with carbonyl compounds

It’s derivatives ( chemicals produced) can be filtered, purified, dried and melting point determined

52
Q

What is Sn1

A

Nucleophilic substitution
Seen in tertiary halogenoalkanes
Has 2 steps
Has one species in RDS

53
Q

What is Sn2

A

Nucleophilic substitution
Seen in primary halogenoalkanes
With 1 step (has transition stage)
Has 2 species in its RDS

54
Q

What is the end-point of a titration

A

The colour change from the indicator which is past the equivalence point at an imbalance of acid or base

55
Q

What is the equivalence point in a titration

A

The exact proportions of acid and base in the titration

56
Q

Ph of equivalence point titration of strong acid + strong base

A

Ph=7

57
Q

Ph of equivalence point titration of strong acid + weak base

A

Ph= <7

58
Q

Ph of equivalence point titration of weak acid + strong base

A

> 7

59
Q

where can’t the equivalence point be determined

A

In the titration of weak acid with weak base because there is an absence of sharp decrease in the graph, only a point of inflection

60
Q

How do indicators work

A

Through dissociation

HI -><- I + H+
therefore when [H]=[In]
[H] = KIn

61
Q

What are buffer solutions made out of

A

Weak acid/ base and their conjugate base/ acid

62
Q

Assumptions made when calculating pH of buffer solutions

A

Remember to add up volume!

-dissociation is negligible
-conc of acid and salt is half when volume is doubled

Chemistry IAL EDEXCEL A-Level (7 decks)

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