organic chemistry Flashcards

1
Q

define homologous series

A

series of organic compounds having the same functional group

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2
Q

define structural isomer

A

same molecular formula but different structural formula

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3
Q

define functional group

A

part of an organic molecule that is largely responsible for the molecules chemical properties

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4
Q

alcohol functional group/prefix/suffix

A

-OH/hydroxy-/-ol

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5
Q

haloalkane functional group/prefix

A

-Cl,Br,I/chloro,bromo,iodo

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6
Q

aldehyde functional group/suffix

A

-CHO/al

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7
Q

ketone functional group/suffix

A

-C(CO)C-/one

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8
Q

carboxylic acid functional group/suffix

A

-COOH/oic acid

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9
Q

ester functional group/suffix

A

-COOC-/oate

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10
Q

acyl chloride functional group/suffix

A

-COCl/oyl chloride

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11
Q

amine functional group/prefix/suffix

A

-NH2/amino/amine

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12
Q

nitrile functional group/suffix

A

-CN/nitrile

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13
Q

How is a sigma bond formed

A

Carbon has 4 electrons in its outer shell. S orbital is filled. 2 of the p orbitals are half-filled and one is completely empty so they overlap

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14
Q

How is a pi bond formed

A

There is 1 electron in each carbon not involved, this electron is in the p orbital. The pi bond is formed by the sideways overlap of the p orbitals. Each carbon contributes one electron to the electron pair. Weaker bond

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15
Q

can pi bonds rotate

A

no because of the double carbon to carbon bond, would otherwise break.

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16
Q

How do you get E/Z isomerism

A

2 different groups attached to the carbons. A double carbon bond. Occurs due to restricted rotation

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17
Q

z / cis isomers

A

non H groups on the same side of the double bond

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18
Q

E/trans isomers

A

non H groups on different sides of the double bond

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19
Q

define stereoisomers

A

same structural formula but a different arrangement of the atoms in space

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20
Q

what is optical isomerism

A

can occur in a wide range of compounds including alkanes with no functional group

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21
Q

order the elements with increasing priority

A

H, C, N, O, Cl, Br

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22
Q

pattern with boiling points as the length of the chain increases

A

Longer the chain, the higher the boiling point because there is more surface contact so there are stronger London forces so more energy is needed to overcome these forces.

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23
Q

pattern with boiling points as the branching of the chain increases

A

The more branching, the lower the boiling point because there are fewer points of contact and the molecules are not as close together so there are weaker London forces meaning less energy is needed to overcome the forces.

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24
Q

why are alkanes unreactive

A

the sigma bonds are strong, C-C is non polar, and there is a small difference in electronegativity between C and H

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25
Q

why is carbon monoxide deadly

A

combines with haemoglobin to form carboxyhaemoglobin which prevent haemoglobin from transporting oxygen.

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26
Q

what are addition reactions

A

2 reactants join together to make one product

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27
Q

what are substitution reactions

A

an atom or group of atoms are replaced by a different atom or group of atoms

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28
Q

what are elimination reactions

A

removal of a small molecule from a large one

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29
Q

what is heterolytic fission

A

where 1 atom takes both electrons from the covalent bond

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30
Q

what is homolytic fission

A

where each atom take one electron from the covalent bond

31
Q

what conditions are needed for free radical substitution

A

UV light

32
Q

what are the different stages of free radical substitution

A

initiation, propagation and termination

33
Q

what is made in initiation give an example

A

molecule — radical+radical

e.g. Cl2 – Cl. + Cl.

34
Q

what is made in propagation give an example

A

radical + molecule —- radical + molecule
Cl. + CH4 —- Ch3. + HCl
CH3. + Cl2 —- CH3Cl + Cl.

35
Q

what is made in termination give an example

A

radical + radical —– molecule
CH3. + CH3. —- C2H6
CH3. + Cl. —- CH3Cl
Cl. + Cl. —– Cl2

36
Q

Why are alkenes more reactive

A

pi bond has a lower enthalpy than a sigma bond so it is broken more easily

37
Q

reactants/conditions for hydrogenation

A

hydrogen/nickel + heat

38
Q

reactants/conditions for halogenation

A

any halogen/room temperature - used as a test for saturation

39
Q

reactants/conditions for hydrogenated halides

A

gaseous or concentrated solution of a hydrogenated halide - can form 2 products

40
Q

reactants/conditions for hydration

A

steam/phosphoric acid - can form 2 products

41
Q

Describe electrophilic addition

A

the double bond in an alkene represents a region of high electron density because of the presence of a pi electron. The high density attracts electrophiles which accepts an electron pair

42
Q

What is a nucleophile

A

electron pair donors

43
Q

what is an electrophile

A

electron pair acceptors

44
Q

what is markownikoff’s rule

A

addition of a hydrogen halide etc to an unsymmetrical alkene forms the major product through the most stable carbocation

45
Q

order of carbocation stability starting with least stable

A

primary (2 H), secondary (1 H), tertiary (0 H)

46
Q

Primary alcohol

A

carbon with OH is attached to one alkyl group

47
Q

Secondary alcohol

A

carbon with OH is attached to two alkyl group

48
Q

Tertiary alcohol

A

carbon with OH is attached to three alkyl group

49
Q

during oxidation what does a primary alcohol produce

A

aldehyde then carboxylic acid

50
Q

during oxidation what does a secondary alcohol produce

A

ketone

51
Q

during oxidation what does a tertiary alcohol produce

A

no reaction

52
Q

what is used to oxidize alcohols

A

potassium dichromate (K2Cr2O7) and sulfuric acid (H2SO4)

53
Q

what color change is observed during oxidation

A

orange to green

54
Q

How can you make sure an aldehyde is produced from oxidation of a primary alcohol

A

distillation - aldehydes have a lower boiling points than alcohols, the aldehyde evaporates before it can react with anymore oxidizing agent

55
Q

Describe heating under reflux

A

allows you to boil a liquid. The vapor condenses in a vertical condenser and returns to the reaction vessel so no substance is lost.

56
Q

dehydration of alcohols

A

H3PO4 or H2SO4 as a catalyst. Water is also produced. Heated under reflux

57
Q

substitution of alcohols. Give example equation

A

heated under reflux with H2SO4 and sodium halide. e.g. C3H7OH + NaBr + H2SO4 —- C3H7Br + NaHSO4 +H2O.

58
Q

examples of nucleophiles

A

:OH-, H2O: and :NH3

59
Q

describe nucleophilic substitution hydrolysis

A

nucleophile approaches carbon atoms attached to halogen on the opposite side of the molecule from the halogen atom. Direction minimizes repulsion between nucleophile and negative halogen. Lone pair of electrons on OH- is attracted and donated to positive carbon. Carbon - halogen bond breaks via heterolytic fission. Alcohol plus halide ion formed. Heated under reflux and aqueous sodium hydroxide is used.

60
Q

cl. reacting with ozone

A
  1. Cl. + O3 —– ClO. + O2
  2. ClO. + O —- Cl. + O2
  3. O3 + O —- 2O2
61
Q

what is the ozone molecule

A

O3

62
Q

breakdown of ozone NO.

A
  1. NO. + O3 —- NO2+O2
  2. NO2. + O —– NO. + O2
  3. O3+ O —- 2O2
63
Q

when is NO. formed

A

During lightening strikes and a result of aircraft travel in the stratosphere

64
Q

CFC properties

A

stable due to string carbon to halogen bond. UV light provides sufficient energy to break carbon halogen bond. As C-Cl bond is lowest enthalpy a CL. is formed

65
Q

properties of aerosols

A

non-toxic, Low BP, low reactivity

66
Q

ozone formation formula

A

O2 + O —- O3

67
Q

consequences of ozone breakdown

A

skin cancer, cataracts, low crop yield, famine as high food prices, more sunburn

68
Q

what is a sigma bond

A

overlap of orbitals between atoms

69
Q

what is optical isomerism

A

same structural formula but are non-superimposable mirror images of each other

70
Q

Describe how to purify an organic product

A
  1. Ensure that the tap of the separating funnel is closed.
  2. Pour the mixture of liquids into the separating funnel, place a stopper in the top of the funnel, and invert to mix the contents.
  3. Allow the layers to settle.
  4. Add some water to see which layer increases in volume - this is the aqueous layer.
  5. Place a conical flask under the separating funnel, remove the stopper and open the tap until the whole of the lower level has left the funnel.
  6. Place a second conical flask under the separating funnel to collect the other layer.
  7. You will now have one conical flask containing the aqueous layer and the other containing the organic layer.
71
Q

How can you remove acid impurities when purifying an organic product

A

Add aqueous sodium carbonate to the separating funnel and invert the mixture. Carbon dioxide is produced and the tap needs to be slowly opened, holding the stoppered separating funnel upside down, to release any gas pressure that may have been built up. Aqueous sodium carbonate layer is removed and organic layer is washed with water before running both layers off into separate conical flasks.

72
Q

How do you dry an organic product

A
  1. Add organic liquid to a conical flask
  2. using a spatula, add some of the drying agent (e.g.CaSO4) to the liquid and gently swirl the contents to mix together.
  3. Place a stopper on the flask to prevent the mixture from evaporating away. Leave for about 10 minutes.
  4. If the solid has all stuck together in a lump, there is still some water present. Add more drying agent until some solid it’s dispersed in the solution as a fine powder.
  5. Decant the liquid from the solid into another flask. If the liquid is dry it should be clear.
73
Q

Why is a tertiary carbocation more stable than a primary carbocation

A

Because there are more alkyl groups around the carbon. Alkyl groups electron releasing/positive inductive effect.

74
Q

Reflux:

A

The continual boiling and condensing of a reaction mixture back into the original container to ensure that the reaction takes place without the contents of the flask boiling dry.