past paper questions

Question 1

define nucleophile

Answer 1

electron pair donor

Question 2

give a use of alkenes

Answer 2

used to make polymers

Question 3

which carbocation will form the most products

Answer 3

-the most stable carbocation (3) will form the most and the least stable (1) will form the least

Question 4

what are the uses of ethanol

Answer 4

-alcoholic drinks
-solvents
-disinfectants
-fuel additive

Question 5

what are the two main ways of producing ethanol

Answer 5

-fermentation of glucose
-hydration of ethene

Question 6

what is the mechanism with reagents and conditions for alkene to alcohol

Answer 6

-mechanism: electrophillic addition /direct hydration
-reagent:

Question 7

what is biofuel

Answer 7

a fuel derived from biological molecules, such as plants

Question 8

what is used to oxidise alcohols

Answer 8

acidified potassium dichromate

Question 9

whats the order of boiling point in ethanol ethanal and ethanic acid

Answer 9

-ethanoic acid> ethanol> ethanal
-ethanioc acid has more hydrogen bonds than ethanol and is a bigger molecule
-ethanol has hydrogen bonding whereas ethanal does not

Question 10

what method is used to form an aldehyde or ketone from alcohol

Answer 10

-distillation

Question 11

what method is used to form a carboxylic acid

Answer 11

reflux apparatus

Question 12

whats the name of the mechanism and reagent used for aldeyde/ketone to alcohol

Answer 12

nucleophillic addition
NaBH₄

Question 13

whats the name of the mechanism and reagent used for aldeyde/ketone to hydroxynitrile

Answer 13

nucleophillic addition
KCN and HCl

Question 14

what is a raecimic mixture

Answer 14

both enantiomers are formed in equal amounts

Question 15

what is an enantiomer

Answer 15

non-superimposable mirror images

Question 16

Explain how enantiomer are formed in 50:50 racemic mixture

Answer 16

C=O bond is planar
Equal chance on nucleophile attacking on from either side

Question 17

describe how rotate the plane of light

Answer 17

raecimic mixture contains equal amounnts of each enantiomer so is optically inactive as it rotates the plane of polarised light in opposite directions

Question 18

describe the solubilty of carboxylic acids in water and are they strong or weak acids

Answer 18

-very soluble in water due to many hydrogen bonding
-weak acid as it only partially disociates in water

Question 19

describe the test for carboxylic acids

Answer 19

-add Na2CO3
-if carboxylic acid present there will be effervescence (CO2)

Question 20

whats the process called when a carboxylic acid reacts with an alcohol and what does it produce using what catalyst

Answer 20

-esterfrication
-ester
-catalyst: conc H2SO4

Question 21

whats the reagent used during the acid hydrolysis of an ester

Answer 21

H2O

Question 22

whats the reagent used during the base hydrolysis of an ester

Answer 22

NaOH

Question 23

what are the uses of amine

Answer 23

nylon, dyes, drugs

Question 24

order of strength of amines as bases

Answer 24

carbon chain amines> ammonia> aromatic amines (nh2 bonded to benzene)
-carbon chain amines has the rR-group which are electron releasing and inc availabilty of lone pair
-aromatic amines weaker as the lone pair of e- on N interacts with delocalised ring of e-

Question 25

what is reagent and condition is needed for the mechanism of benzene to cyclohexane

Answer 25

-H2(g) -nickel catalyst

Question 26

compare benzene to kekules structure

Answer 26

-benzene is more stable than kekules structure -due to the delocalised ring of electrons -the expected AH= -360 kJmol-1 -the actual AH= 152 kJmol-1 (less exothermic)