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A Level Chemistry > 3.7 Optical Isomerism & 3.8 Aldehydes And Ketones > Flashcards

3.7 Optical Isomerism & 3.8 Aldehydes And Ketones Flashcards

(40 cards)

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1
Q

Name Compound CH3C(OH)(CN)CH2CH2CH3

A

2-hydroxy-2-methylpentanenitrile

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2
Q

How to distinguish between enantiomers

A
  • Use of plane polarised light
  • light rotated in oppose directions equally
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3
Q

What type of product is formed when an aldehyde is reduced?

A

primary alcohol

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4
Q

What is the definition of stereoisomerism?

A

molecules with the same structural formula but different arrangement of atoms in space

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5
Q

What are optical isomers?

A

non-superimposable mirror images

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6
Q

What do chiral molecules do to plane-polarised light?

A

rotate it

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7
Q

What forms when an unsymmetrical ketone reacts with KCN?

A

A mixture of enantiomers

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8
Q

Why are racemic mixtures optically inactive?

A

They contain equal amounts of enantiomers which cancel out the optical activity

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9
Q

What is the definition of structural isomerism?

A

molecules with the same molecular formula but different structural formulae

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10
Q

What forms when a ketone reacts with HCN?

A

Hydroxynitrile

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11
Q

What is another name of a chiral centre

A

sterogenic centre

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12
Q

What is a chiral carbon

A

carbon atom bonded to 4 different groups

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13
Q

Name product formed when pentanal is reduced with NaBH4

A

pentan-1-ol

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14
Q

What is meant by a sample which is enantiomerically pure

A

sample which only contains one optical isomer

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15
Q

What is the nucleophile in the reaction of aldehydes with NaBH4

A

H^-

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16
Q

Why are racemic mixtures optically inactive

A

They contain equal amounts of enantiomers which cancel out the optical activity

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17
Q

What is the effect of enantiomers on plane polarised light

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A

They rotate the plane of polarised light

18
Q

Name product formed when butanal is reacted with KCN

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A

2-hydroxypentanenitrile

19
Q

What is observed when Fehlings reagent is mixed with an aldehyde

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A

brick-red precipitate forms

20
Q

What is another name for a racemix mixture

21
Q

Name product formed when butanone is reduced with NaBH4

22
Q

Condition needed in reduction of an aldehyde or ketone

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A

acidic solvent

23
Q

What are enantiomers

Study These Flashcards
A

Non-superimposable mirror images

24
Q

What is a racemic mixture

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A

a mixture which contains equal amount of enantiomers

25
What is the hazard of using KCN
it is highly toxic
26
State the relationship between two chiral molecules with the same structural formula.
non-superimposable mirror images
27
Which compound does not show stereoisomerism? a. 1,2-dichloropropane b. 1,3-dichloropropene c. 1,2-dichloropropene d. 1,3-dichloropropane
d
28
Give the chemical formula of the reagent used to test for Ba^2+ and the observation made.
reagent : H2SO4 observation : white precipitate formed
29
Give the chemical formula of the reagent used to test for the SO4^2- and the observation made.
reagent : BaCl2 Observation : white precipitate
30
Which one of the following statements about but-2-enal, CH3CH=CHCHO, is not true? A It has stereoisomers. B It shows a strong absorption in the infra-red at about 1700 cm−1. C It will turn an acidified solution of potassium dichromate(VI) green. D It can be dehydrated by concentrated sulphuric acid.
D
31
Which one of the following reactions will produce an organic compound that has optical isomers? A dehydration of butan-2-ol by heating with concentrated sulphuric acid B reduction of pentan-3-one by warming with NaBH4 C addition of Br2 to 3-bromopropene D reduction of 2,3-dimethylpent-2-ene with H2 in the presence of a nickel catalyst
D
32
In which one of the following mixtures does a redox reaction occur? A ethanal and Tollens’ reagent B ethanoyl chloride and ethanol C ethanal and hydrogen cyanide D ethanoic acid and sodium hydroxide
A because in silver mirror there is an Ag^+ ion (fehlings has Cu^2+ ion) As Ag+ goes to Ag ethanal therefore gets oxidised as Ag gets reduced
33
What reagent is used to reduce an aldehyde or a ketone
NaBH4
34
35
- leave blank as you need to do the solution again
36
37
38
Only name and complete mechanism
Elimination
39
CH32COCH2CHO + 4[H] -> CH3CH(OH)CH2CH2OH
40
Name product of reaction between pentan-3-one and KCN
2-ethyl-2-hydroxybutanenitrile

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