Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Advanced Higher Chemistry Definitions > Unit 2 > Flashcards

Unit 2 Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

Nucleophiles

A

Nucleophiles are negatively charged ions or neutral molecules that are electron rich.

They are attracted towards atoms bearing a partial or full + charge.

They are capable of donating an electron pair to form a new covalent bond.

Nucleophiles are nucleus loving and so nucleophiles are attracted and will attack species with a + charge.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Electrophiles

A

Electrophiles are positively charged ions or neutral molecules that are deficient in electrons.

They are attracted towards atoms bearing a partial or full - charge.

They are capable of accepting an electron pair to form a new covalent bond.

Electrophiles are electron loving and so Electrophiles are attracted and will attack species with a - charge.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

2 types of stereoisomer

A

Geometric
Optical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Geometric isomers

A

Arise due to a lack of free rotation around a bond, frequently C=C, but not always.
Must have 2 different groups attached to each of the C atoms.
Non-superimposable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Cis isomer

A

The 2 largest groups are on the same side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Trans isomer

A

The 2 largest groups are on opposite sides.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Optical isomers

A

Arise as they have a chiral centre
They are asymmetric, non-superimposable mirror images of each other.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Chiral

A

4 different groups arranged tetrahedrally around a central carbon atom.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Enantiomers

A

Optical isomers can be described as enantiomers.

They have identical physical and chemical properties except :

Their effect on plane polarised light
Their reaction with other chiral molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Racemic mix

A

Contains a 50/50 mix of 2 enantiomers.
This is optically inactive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How to differentiate between 2 optical isomers ?

A

Subject them to plane polarised light.

Each enantiomer will rotate the light by the same angle but in opposite directions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Drugs

A

Substances that alter the biochemical processes in the body.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Medicine

A

A drug that has a beneficial impact on the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What do medicines contain ?

A

They contain the drug and often have other added ingredients such as fillers to add bulk or sweeteners to improve taste.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Agonists

A

Agonists MIMIC the natural compound and bind to the receptor molecules to produce a similar response to it.
The drug form ionic bonds with the receptor.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Antagonists

A

Antagonists prevent the natural compound from binding, and so blocks the natural response from occurring.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Enzyme inhibitors

A

Drugs that act on enzymes are classed as enzyme inhibitors and act by binding to the active site of the enzyme. This blocks the reaction normally catalysed here.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Pharmacophore

A

The structural fragment of a drug molecule that allows it to form interactions with a receptor.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Experimental determination of structure

A

Elemental microanalysis
Mass spectroscopy
Infrared spectroscopy
NMR spectroscopy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Elemental microanalysis

A

Used to determine the masses of C, H, O, S and N in a sample of an organic compound, in order to determine its empirical formula.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Empirical formula

A

The simplest ratio of elements in a substance/ molecule.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Mass spectroscopy

A

Used to determine the accurate GFM and structural features of an organic compound.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Infrared Spectroscopy

A

Used to determine and identify certain functional groups in an organic compound.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

NMR Spectroscopy

A

Gives information about different chemical environments of H atoms in an organic compound. Allows recognition of how many H atoms are in each environment.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Molecular Orbitals

A

Molecular orbitals are generated when atomic orbitals combine.
The number of molecular orbitals formed is always equal to the number of atomic orbitals that combine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Sigma bond

A

Molecular orbitals overlap end on.
Single bonds are sigma bonds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Pi bond

A

Molecular orbitals overlap side on.
Double bonds contain 1 pi bond and 1 sigma bond.
Triple bonds contain 2 pi bonds and 1 sigma bond.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Pi bond V sigma bond

A

Pi bonds are weaker than sigma bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Hybridisation

A

Hybridisation is the process of mixing atomic orbitals within an atom, to form a set of new atomic orbitals called hybrid orbitals. These hybrid orbitals are degenerate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

sp3 hybridisation

A

Found in alkANES
Only have sigma bonds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

sp2 hybridisation

A

Found in alkENES
Have sigma and pi bonds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

sp hybridisation

A

Found in alkYNES
Has 2 pi bonds and 1 sigma bond.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

HOMO

A

The orbital containing electrons with the highest energy is known as the Highest Occupied Molecular Orbital.

34
Q

LUMO

A

The lowest energy anti-bonding orbital which is vacant is called the Lowest Unoccupied Molecular Orbital.

35
Q

Chromophore

A

A group of atoms within a molecule responsible for the absorption of light in the visible region of the spectrum.

36
Q

Conjugation

A

Alternating single and double carbon to carbon bonds.

37
Q

Reaction of haloalkanes

A

Elimination : to produce an alkene

Nucleophilic Substitution : to produce an ( alcohol, nitrile OR ether )

38
Q

How are haloalkanes classified ?

A

Haloalkanes are classified according to the number of alkyl groups (R) attached to the carbon containing the halogen atom.

39
Q

Haloalkanes

A

Haloalkanes are substituted alkanes in which one or more hydrogen atoms are replaced by a halogen atom.

40
Q

3 types of monohaloalkanes

A

Primary
Secondary
Tertiary

41
Q

Haloalkane Elimination

A

Monohaloalkane + NaOH (eth) ——————————> Alkene

Note : The OH- removes a H atom from a C atom adjacent to the halogen. The halogen is
ejected.

42
Q

Haloalkanes Nucleophilic Substitution reactions

A

Monohaloalkane + NaOH (aq) ——————————> Alcohol

Monohaloalkane + NaCN (eth) ——————————> Nitrile

Monohaloalkane + Alcoholic Alkoxide ——————————> Ether

Note : Alkali metal + Alcohol ——————————> Alcoholic Alkoxide

43
Q

Mechanisms of nucleophilic substitution reactions

A

2 types of mechanisms :

SN1
SN2

44
Q

SN1

A

1st order with respect to the haloalkane
One molecule involved in the slowest step
Tertiary haloalkanes usually undergo SN1
A Trigonal planar CARBOCATION intermediate is formed.

45
Q

What is formed in the SN1 mechanism ?

A

A Trigonal planar carbocation intermediate, stabilised by the inductive effect from the CH3 groups.

46
Q

SN2 mechanism

A

2nd order
2 molecules involved in the slowest step
Primary haloalkanes usually undergo SN2
Proceeds via a 5 centred ( Trigonal bipyramidal ) transition state.

47
Q

What does the SN2 mechanism proceed by ?

A

Via a 5 centred Trigonal bipyramidal transition state

48
Q

Alcohols

A

Alcohols are substituted alkanes, where one or more of the H atoms is replaced with a hydroxyl functional group.

49
Q

Preparation of alcohols

A

Nucleophilic Substitution
Hydration / Addition
Reduction

Monohaloalkane + NaOH (aq) ———————————-> alcohol

                                   conc. H2SO4 Alkene + water  ———————————-> alcohol

Aldehyde/Ketone + LiAlH4 ———————————-> alcohol

50
Q

Reactions of Alcohols

A

Oxidation (using acidified permanganate)
Dehydration (using conc. H2SO4)
Condensation / Esterification (using conc. H2SO4)

Primary alcohol ———————————-> aldehyde

Secondary alcohol ———————————-> ketone

Alcohol ———————————-> alkene

Alcohol + Carboxylic acid ———————————-> ester

51
Q

Physical properties of alcohols

A

Hydroxyl group gives rise to H bonding

H bonding results in a higher boiling point

The polar -OH group allows alcohols to be miscible in water.
As the C chain increases, solubility decreases.

52
Q

Ethers

A

Ethers are substituted alkanes in which a H-atom is replaced with an alkoxy functional group.

R’ ——O—— R”

53
Q

Naming ethers

A

The smaller R—O is given a position and ends in oxy

E.g. methoxy
ethoxy
propoxy etc.

The longest chain is named after an alkane.

E.g. methane
ethane
propane Etc.

54
Q

Preparation of ethers

A

Nucleophilic substitution

Monohaloalkane + alcoholic alkoxide ———————————-> ether

55
Q

Properties of ethers

A

Due to a lack of H bonding, ethers have a lower boiling point than the corresponding isomeric alcohols.

Large ethers are INSOLUBLE in water due to increased molecular size.

56
Q

Uses of ethers

A

Ethers are commonly used as SOLVENTS; since they are relatively INERT chemically and dissolve easily.

57
Q

Preparation of Alkenes

A

Elimination reaction
Dehydration of an alcohol

Monohaloalkane + NaOH(eth) ———————————-> alkene

alcohol ———————————-> alkene + H2O

58
Q

What process do Alkenes react by ?

A

Electrophilic Addition

59
Q

Reactions of Alkenes

A

Hydrogen + alkene ———————————-> alkane

Halogen + alkene ———————————-> dihaloalkane

Hydrogen Halide + alkene ———————————-> monohaloalkane

Water + alkene (acid catalyst) ———————————-> alcohol

60
Q

Markovnikovs Rule

A

Used to determine which of 2 products is in greater yield.

The major product is the one in which the H atom attaches to the C of the double bond that has the greater number of Hs bonded to it.

61
Q

Preparation of Carboxylic acids

A

Oxidation of primary alcohols (using XS acidified dichromate) / aldehydes (using acidified dichromate)

Hydrolysis of ( nitriles, esters or amides ) using an aqueous alkali

Nitrile
Ester + H2O ——————————> Carboxylic acid
Amide

62
Q

Reactions of Carboxylic acids

A

Carboxylic acid

+ metal/base ———————-> salt
+ alcohol ( conc. H2SO4 ) ———————-> ester
+ amine ———————-> alkyl-ammonium salt
+ LiAlH4 ———————-> primary alcohol

63
Q

Amines

A

Amines are organic derivatives of ammonia, in which one or more H atoms are replaced by an alkyl group.

64
Q

How are amines classified ?

A

Classified according to the number of alkyl groups attached to the nitrogen atom.
Can be classed as :
Primary
Secondary
Tertiary

65
Q

Physical properties of amines

A

Primary and secondary amines contain a polar N—H bond and so display H bonding.
As a result, they have higher bpts than isomeric tertiary amines.
Tertiary amines do not display H bonding

All 3 can H-bond with water, thus explaining the appreciable solubility of the shorter chain length amines in water.

66
Q

Reactions of Amines

A

Amine + acid ———————-> alkyl-ammonium salt

Alkyl ammonium salt + HEAT ———————-> amide

67
Q

Benzene

A

C6H6
The simplest member of the class of aromatic hydrocarbons

68
Q

How are benzene rings stable ?

A

The stability of the benzene ring is due to the delocalisation of electrons in the conjugated system.

69
Q

What method does benzene react by ?

A

Electrophilic SUBSTITUTION

The H/ Hs are replaced by atoms or groups (the electrophiles)

70
Q

Phenyl group

A

A benzene ring in which one H atom has been substituted by another group (known as a phenyl group) C6H5

71
Q

Reactions of benzene

A

Alkylation
Sulfonation
Halogenation
Nitration

72
Q

Alkylation

A

Benzene + AlCl3 + R-Cl ———————-> alkylbenzene

73
Q

Halogenation

A

Benzene + AlCl3 + X2 ———————-> halobenzene

74
Q

Sulfonation

A

Benzene + conc. H2SO4 ———————-> benzenesulfonic acid

75
Q

Nitration

A

Benzene + conc. H2SO4 + HNO3 ———————-> nitrobenzene

76
Q

Bond fission

A

The process of bond breaking is known as bond fission.
A bond can break in 2 ways :

Homolytic fission
Heterolytic fission

77
Q

Homolytic fission

A

Occurs when non-polar covalent bonds are broken.
Free radicals are produced.
Caused by HIGH ENERGY UV light.
Can produce multiple undesirable products.

78
Q

Heterolytic Fission

A

Occurs when polar covalent bonds are broken.
Ions are produced.
Double headed arrows are used.

Results in far fewer products than Homolytic fission, and as a result are better suited in the synthesis of organic compounds.

79
Q

sp3 hybridisation

A

One s atomic orbital mixes with three p atomic orbitals to form 4 hybrid orbitals, which are degenerate.

80
Q

sp2 hybridisation

A

One s atomic orbital mixes with two p atomic orbitals to form 3 hybrid orbitals, which are degenerate.

The remaining p orbital is left unhybridised.

81
Q

sp hybridisation

A

One s atomic orbital mixes with one p atomic orbitals to form 2 hybrid orbitals, which are degenerate.

The remaining two p orbitals are left unhybridised.

Advanced Higher Chemistry Definitions (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions