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Chemistry Year 1 and Year 2 > chapter 26 > Flashcards

chapter 26 Flashcards

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1
Q

secondary alcohols are oxidized to? and under what conditions

A

ketones
refluxed under acidified conditions

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2
Q

the oxidizing agent in the oxidization of secondary alcohols

A

potassium dichromate

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3
Q

primary alcohols are oxidized to what, and under what conditions
oxidizing agent?

A

aldehydes
distilled under acidic conditions
potassium dichromate

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4
Q

can tertiary alcohols be oxidised

A

no

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5
Q

what group is present in the structure of both aldehydes and ketones

A

a carbonyl group

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6
Q

the position of the carbonyl group in a ketone and aldehyde

A

in a ketone, the carbonyl group is joined to two different carbons in the chain, while in aldehydes, the carbonyl group is found at the end of the carbon chain

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7
Q

the ending of a molecular structure of an aldehyde

A

CHO

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8
Q

aldehydes are oxidized to

A

carboxylic acids

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9
Q

conditions for the oxidization of aldehydes and the oxidizing agent

A

reflux under acidic conditions
potassium dichromate

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10
Q

when an aldehyde is oxidized, there is a color change in the dichromate solution from

A

orange to green

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11
Q

do ketones undergo oxidization

A

nope

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12
Q

why is the C=O bond polar

A

because of the difference in electronegativity values of O and C

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13
Q

nucleophile

A

a electron donor

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14
Q

aldehydes and ketones can be reduced to
the reducing agent for such reactions?

A

alcohols
sodium tetrahydridoborate (III) (NaBH4)

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15
Q

in nucleophilic addition, the C=O pie bond breaks in a ……………. manner forming a …………….. charged intermediate

A

heterolytic
negatively

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16
Q

in nucleophilic addition, the hydride ion is provided by

A

the NaBH4

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17
Q

Describe what happens in nucleophilic addition

A

lone pair on the hydride ion is attracted and donated to the partially positive carbon atom of the C=O bond. This forms a dative covalent bond

in nucleophilic addition, the C=O pie bond breaks in a heterolytic manner forming a negatively charged intermediate

the oxygen atom in C-O bond in the intermediate donates a lone pair of electrons to a hydrogen atom in a water molecule.

An alcohol is formed as a result

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18
Q

an aldehyde reacts with hydrogen cyanide to form
under what conditions
where do we get the hydrogen cyanide from

A

a hydroxynitrile
acidic conditions
NaCN

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19
Q

why is the reaction between an aldehyde and hydrogen cyanide important

A

it provides a way to extend the carbon chain length

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20
Q

on which atom is the lone pair in CN on

A

on C

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21
Q

brady’s reagent

A

a solution of 2,4-DNP dissolved in methanol and sulfuric acid

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22
Q

describe a test to identify a carbonyl group in either an aldehyde and a ketone

A

add a 5cm depth of a solution of 2,4-DNP to a clean test tube
add 3 drops of the unknown compound. leave to stand
a yellow/orange precipitate forms if there is a carbonyl group(aldehyde or ketone) present

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23
Q

if no crystals form when brady’s reagent is added to a solution containing a ketone or an aldehyde

A

add more sulfuric acid

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24
Q

how do we identify whether a carbonyl group is exactly in a certain molecule

A

the precipitate formed after adding Brady’s reagent is filtrated
then it is recrystallized
the melting point is then measured and compared with known values

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25
Q

tollen’s reagent

A

a solution of silver nitrate in aqueous ammonia

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26
Q

in the tollen’s reagent, what acts as the oxidizing reagent

A

Silver ions

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27
Q

an aldehyde is oxidized to

A

a carboxylic acid

28
Q

if an aldehyde is present in the tollen’s reagent test, what happens

A

a silver mirror is formed

29
Q

will the tollen’s reagent be able to identify ketones and why

A

no, because ketones cannot be oxidized further

30
Q

if there are two carboxylic acids in a compound, the name changes to the corresponding alkane, with a………… added at the end

A

dioic acid

31
Q

carboxylic acids can form hydrogen bonds with two compounds, what are these

A

water and other carboxylic acids

32
Q

name the factor that decreases the solubility of carboxylic acids

A

an increase in the number of atoms in the non polar carbon chain

33
Q

what happens to the solubility of carboxylic acids as the acid group(COOH) increases

A

the solubility increases further

34
Q

carboxylic acids with up to 4 carbon atoms are all soluble in water, true or false

A

true

35
Q

are carboxylic acids strong acids?

A

no they are rather weak acids

36
Q

products formed when carboxylic acids react with metals

A

salt and hydrogen gas

36
Q

products formed when carboxylic acids react with metals

A

salt and hydrogen gas

37
Q

carboxylic acids react with metal carbonates to form

A

salt, water and carbon dioxide

38
Q

carboxylic acid derivatives

A

compounds that can be hydrolysed to form the parent carboxylic acid

39
Q

in hydrolysis, which bond breaks in a carboxylic acid derivative

A

the single bond between the carbon in the acyl group and a different group

40
Q

suffix for acyl chlorides

A

oyl chlorides

41
Q

how are acyl chlorides prepared

A

by reacting carboxylic acids with thionyl chloride

42
Q

molecular formula of thionyl chloride

A

SOCl2

43
Q

what are the products formed from the reaction of carboxylic acids with thionyl chloride

A

an acyl chloride, Sulphur dioxide and HCl gas
Both gases are toxic

44
Q

acyl chlorides are very unreactive, true or false

A

false they are very reactive

45
Q

acyl chlorides react by losing ….?

A

their chloride ion while retain the C=O bond

46
Q

nucleophile

A

an electron pair donor

47
Q

condensation reaction

A

a reaction in which two molecules react together to form a larger molecule with the elimination of a small molecule

48
Q

acyl chlorides react with alcohols or phenols to form

A

an ester and HCl

49
Q

acyl chlorides react with water to form

A

an carboxylic acid and HCl

50
Q

why should the reaction between acyl chlorides and water be carried out under anhydrous conditions

A

because if not, the acyl chloride will react violently with water to form the carboxylic acid

51
Q

acyl chlorides react with ammonia to form

A

Primary amide

52
Q

acyl chlorides react with amines to form

A

a secondary amide

53
Q

how are acid anhydrides formed

A

from the condensation reaction between two molecules of carboxylic acid

54
Q

which is more reactive, an acyl chloride, or an acid anhydride

A

acyl chlorides

therefore acid anhydrides are more likely to be used in lab preparations while acyl chlorides might be too reactive

55
Q

acid anhydrides react with alcohols to form

A

an ester and a carboxylic acid

56
Q

functional group of esters

A

RCOOR

R stands for a carbon group

57
Q

esters are named from backwards to forwards, true or false

A

true

58
Q

esterification

A

the reaction of a carboxylic acid with an alcohol to form an ester and water

59
Q

can carboxylic acids react with phenols to form esters

A

no they cannot, because they are not reactive enough to do so.
instead acyl chlorides and acid anhydrides are used

60
Q

do esters react with acyl chlorides

A

no

61
Q

acid hydrolysis of esters is the reverse of

A

esterification

62
Q

in acid hydrolysis, the ester is heated under ……………… with ……………………..

A

reflux
dilute aqueous acid

63
Q

in acid hydrolysis, the ester reacts slowly with water. but the reaction is sped up by ……………………
what acts as the catalyst

A

catalysis

the dilute aqueous acid

64
Q

alkaline hydrolysis is also known as

A

saponification

65
Q

in alkaline hydrolysis, the ester is heated under…………… with ……………… to form a ……………………. and an ……………….

A

reflux
aqueous hydroxide ions
carboxylate ion
alcohol

Chemistry Year 1 and Year 2 (15 decks)

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