3. Organic AS

Question 1

define homologous series

Answer 1

a group of organic compounds that have the same functional group, but each successive member differs by CH2

Question 2

define structural formula

Answer 2

shows how the atoms are bonded to each carbon atom in a molecule

Question 3

define displayed formula

Answer 3

2D representation of an organic molecule showing all its atoms and their bonds

Question 4

define skeletal formula

Answer 4

simplified display formula with all the carbon and hydrogen bonds removed

Question 5

what is the general formula of alcohols?

Answer 5

C(n)H(2n+1)OH

Question 6

what is the general formula of aldehydes?

Answer 6

C(n)H(2n+1)CHO

Question 7

what is the general formula of ketones?

Answer 7

C(n)H(2n)O

Question 8

what is the general formula of carboxylic acids?

Answer 8

C(n)H(2n+1)COOH

Question 9

what is the general formula of esters?

Answer 9

C(n)H(2n)O2

Question 10

what is the general formula of amines?

Answer 10

C(n)H(2n+1)NH2

Question 11

what is the general formula of nitriles?

Answer 11

C(n)H(2n+1)CN

Question 12

define molecular formula

Answer 12

shows the number and type of each atom in a molecule

Question 13

define empirical formula

Answer 13

shows the simplest whole number ratio of the elements present in one molecule of the compound

Question 14

define aliphatic compound

Answer 14

straight or branched chain and also includes cyclic organic compounds that do not contain a benzene ring

Question 15

what are structural isomers?

Answer 15

compounds that have the same molecular formula but different structural formula

Question 16

what is chain isomerism?

Answer 16

when compounds have the same molecular formula, but their longest hydrocarbon chain is not the same e.g. pentane and 2,2-dimethy propane

Question 17

what is positional isomerism?

Answer 17

arise from differences in the position of a functional group in each isomer. the functional group can be located on different carbons. e.g butanol and 2-butanol

Question 18

what is functional group isomerism?

Answer 18

same molecular formula but different functional group e.g. butanol and ethoxyethane

Question 19

how does cracking work?

Answer 19

large hydrocarbon molecules are fed into a steel chamber and heated to a high temp and passed over aluminium oxide catalyst

Question 20

what are the products of complete combustion?

Answer 20

co2 and h2O

Question 21

what are the products of incomplete combustion?

Answer 21

CO/C and H2O

Question 22

what is the initiation step of free radical substitution?

Answer 22

Question 23

what is homolytic fission?

Answer 23

when each atom takes one electron from the covalent bond

Question 24

what is the propagation step?

Answer 24

Question 25

what is the termination step?

Answer 25

Question 26

what are the products from nucleophilic substitution?

Answer 26

a halogen is substituted for another atom or group of atoms. products formed are alcohols, amines, and nitriles

Question 27

what are the products from elimination?

Answer 27

a hydrogen halide is eliminated and an alkene is formed

Question 28

what are the reagents and conditions for the formation of alcohols undergoing nucleophilic substitution?

Answer 28

reagents: aqueous NaOH or KOH with ethanol conditions: warm

Question 29

what are the reagents and conditions for the formation of nitriles undergoing nucleophilic substitution?

Answer 29

reagents: ethanolic solution of KCN conditions: heated under reflux

Question 30

what are the reagents and conditions for the formation of amines (primary) undergoing nucleophilic substitution?

Answer 30

reagents: ethanolic solution of excess ammonia conditions: heated under pressure

Question 31

what are the reagents and conditions for elimination?

Answer 31

reagents: ethanolic NaOH conditions: heated

Question 32

give the free radical substitution for when CFCs react with the ozone

Answer 32

Question 33

describe the sigma and pie bonds in ethene and how they arise

Answer 33

1)Each carbon atom uses three of its four electrons to form σ bonds 2)Two σ bonds are formed with the hydrogen atoms One σ bond is formed with the other carbon atom 3)The fourth electron from each carbon atom occupies a p orbital which overlaps sideways with another p orbital on the other carbon atom to form a π bond 4)This means that the C-C is a double bond: one σ and one π bond

Question 34

how are sigma bonds formed?

Answer 34

from the end to end overlap of atomic orbitals

Question 35

how are pie bonds formed?

Answer 35

sideways overlap of adjacent p orbitals

Question 36

what is the positive inductive effect?

Answer 36

Alkyl groups push electron density towards the carbocation making it energetically more stable; the more alkyl groups the carbocation is bonded to, the more stabilised it is (tertiary>secondary>primary)

Question 37

what are the reagents, conditions and products of hydrogenation (electrophilic addition)?

Answer 37

Question 38

what are the reagents, conditions and products of electrophilic addition with steam?

Answer 38

Question 39

what are the reagents, conditions and products of electrophilic addition with hydrogen halides?

Answer 39

Question 40

what are the reagents, conditions and products of electrophilic addition with halogens?

Answer 40

Question 41

how do you test whether a compound is unsaturated?

Answer 41

mix with bromine water which should decolorise

Question 42

why are the disposal of polymers a challenge?

Answer 42

due to their unreactivity, non-biodegradability and formation of harmful combustion when burnt

Question 43

what are some of the solutions of plastic pollution?

Answer 43

feedstock recycling, mechanical recycling,

Question 44

what are primary alcohols oxidised to and how?

Answer 44

aldehydes and using acidified K2Cr2O7

Question 45

what is the colour change when primary and secondary alcohols are oxidised using K2Cr2O7?

Answer 45

orange to green

Question 46

what are secondary alcohols oxidised to and how?

Answer 46

ketones and using acidified K2Cr2O7

Question 47

how can you form an alcohol using electrophilic addition?

Answer 47

reagents: alkene and steam conditions: heat Phosphoric acid catalyst

Question 48

how can you form an alcohol using oxidation?

Answer 48

reagents: alkenes and cold dilute KMnO4 conditions: shaking of reagents

Question 49

how can you form an alcohol using nucleophilic substitution?

Answer 49

reagents: halogenoalkanes and aqueous NaOH conditions: heat

Question 50

how can you form an alcohol using reduction?

Answer 50

reagents: aldehydes and ketones conditions: NaBH4 or LiAlH4

Question 51

how can you form an alcohol using hydrolysis?

Answer 51

reagents: esters conditions: dilute acid or alkali and heat

Question 52

what can primary alcohols be oxidised to?

Answer 52

aldehydes and then further oxidation to carboxylic acids

Question 53

what is the oxidising agent for alcohols?

Answer 53

acidified K2Cr2O7 or acidified KMnO4

Question 54

how can you test for an aldehyde?

Answer 54

Fehling's (blue to brick red) or Tollen's reagent (silver nitrate in excess ammonia, form a silver mirror)

Question 55

what happens if you test ketones using Fehling's or Tollen's reagent?

Answer 55

no change as they cannot be oxidised further

Question 56

what are the reagents and conditions of elimination reaction of alcohols?

Answer 56

reagents: hot catalyst Al2O3 powder/excess hot conc H2O4/H3PO4

Question 57

how do you test for carboxylic acids?

Answer 57

add NaHCO3 and CO2 gas is formed