Organic Chemistry Flashcards Preview

Chemistry > Organic Chemistry > Flashcards

Flashcards in Organic Chemistry Deck (74)
Loading flashcards...
1
Q

what are hydrocarbons?

A

molecules composed mainly of carbon and hydrogen atoms.

2
Q

how many bonds does carbon form?

A

4

3
Q

tetrahedral arrangement

A

109.5 degrees apart from each other

4
Q

homologous series

A

a group of compounds that have the same general formula or have a unique functional group.

5
Q

what are the defining features of alkanes?

A
  • single C-C bonds
  • saturated because the backbone is completely surrounded by carbons
  • CnH2n+1
6
Q

9

A

non

7
Q

10

A

dec

8
Q

11

A

undec

9
Q

12

A

dodec

10
Q

properties of alkanes

A
  • shorter have lower BP because of less intermolecular bonds, less energy is needed to overcome them
  • at room temp: ethane, propane and butane are gases
  • larger are liquids and some are solids
  • insoluble in water
  • soluble in organic solvents
  • shorter are more volatile (evaporate easily), increasing flash point (easier to combust)
  • larger alkanes are more viscous
11
Q

viscosity

A

depends on the interaction between molecules. Increased length, means increased strength of dispersion forces and thus viscosity increases.

12
Q

alkyl groups

A

refers to branching from the backbone

13
Q

isomer

A

chemical substances that have the same chemical formula but different structural formulas

14
Q

what effect does branching have on chemical properties?

A

increased branching, decreased surface area and hence a decrease in intermolecular bonding, so a decreased BP

15
Q

what are the features of alkenes?

A
  • double C-C bond
  • unsaturated because carbon backbone is not completely surrounded
  • CnH2n
16
Q

is a double bond a functional group?

A

yes

17
Q

naming alkenes

A
  • determine longest chain

- number the carbons closest to double bond and give the bond a number

18
Q

properties of alkenes

A
  • smaller have lower bP
  • ethene, propene and butene are gases at room temp
  • larger are liquids or solids (more than 16C)
  • insoluble in water
  • soluble in organic solvents
  • C-C double bond makes the, highly reactive
19
Q

what reactions can alkanes participate in?

A
  • combustion

- substitution

20
Q

what is a substitution reaction?

A

an atom or a functional group is swapped by another atom or group of atoms

21
Q

what products are them of a substitution reaction?

A

the new hydrocarbon and the atoms removed that form a small molecule

22
Q

what can alkanes form in substitution reactions?

A

halogenated hydrocarbons, amines, alcohols

23
Q

important consideration in substitution reactions?

A

only saw one hydrogen atom at a time for a new atom or group of atoms
if a reaction occurs between an alkane and an excess of a new atom (eg. Cl2), a series of substitution reactions can occur

24
Q

halogens in halogenated hydrocarbons

A
  • only need one electron and are thus highly reactive and electronegative
  • hydrogen is swapped for one
25
Q

naming a halogenated hydrocarbon

A
  1. longest chain
  2. identify location of functional group
  3. use numbers to show position
  4. functional groups with functional groups in alpha order
26
Q

what are amines? how are they formed?

A
  • amino functional groups that have a nitrogen attached to two hydrogen atoms
  • polar due to hydrogen bond
  • can be produced by a substitution reaction where a hydrocarbon reacts with ammonia (NH3)
27
Q

primary amines

A

C atom attached to NH2 is attached to one other alkyl group

28
Q

secondary amines

A

C atom attached to NH2 is attached to two other alkyl groups

29
Q

tertiary amines

A

C atom attached to NH2 is attached to three other alkyl groups

30
Q

nomenclature priority

A

most: carboxylic acid, ester, aldehyde, ketone, alcohol, amine, alkyne, alkene, alkane: least

31
Q

how is an amine named when amine is priority?

A

becomes suffer -amine eg. propylamine

32
Q

how is an amine named when amine is not priority?

A

amino - propanol

33
Q

why are amines polar? what does this mean?

A
  • asymmetrical
  • can hydrogen bond with water (H has a slight positive in the amine and bonds to negative O in water)
  • can be soluble in water but as gets longer, less soluble
34
Q

features of alcohols

A
  • hydroxyl functional group (OH)
35
Q

how can an alcohol be formed?

A

a substation reaction where an alkane reacts with water or a strong base or OH-

36
Q

primary alcohol

A

OH attacked to C and one other alkyl group

37
Q

secondary alcohol

A

OH attacked to C and two others alkyl group

38
Q

tertiary alcohol

A

OH attaches to C and three other alkyl groups

39
Q

naming alcohols with priority

A

butan-1-ol

ol

40
Q

naming alcohols without priority

A

2 hydroxy butanoic acid

41
Q

properties of alcohols

A
  • polar due to OH
  • not symmetrical
  • hydrogen bondning
  • soluble in water (dependent on length)
42
Q

what is an addition reaction?

A

when a small molecule is added and the double C-C bond is disrupted creating an entry point

43
Q

how many products in addition reactions?

A

one

44
Q

how is an alkane made from an alkene? what is this reaction called?

A

alkene plus H2 with UV/heat produces an alkane

- hydrogenation reaction

45
Q

alkene to a halogenated alkane addition reaction

A

alkene plus HCl or Cl2 etc. with UV or heat forms a halogenated alkane

46
Q

alkene to amine with addition reaction

A

alkene plus NH3 with UV/heat forms an amine

47
Q

alkene to an alcohol addition reaction

A

alkene plus water with H3PO4 at 300 degrees forms an alcohol

48
Q

how does an alcohol form a carboxylic acid?

A

primary alcohols are the reductant and undergo oxidation with an oxidant (Cr2O72-/H+ or MnO4-/H+). intense heat and long reaction time are needed

49
Q

colour changes when redox reaction occurs

A

Cr2O72- is orange and Cr3+ is green

MnO4- is purple and Mn2+ is colourless

50
Q

how is an aldehyde made?

A

intermediate step in forming carboxylic acids. primary alcohol reacts with Cr2O72-/H+ or MnO4-/H+ in mild conditions for less time

51
Q

what is an aldehyde?

A

CHO group

- ends in al

52
Q

how is a ketone made?

A

if a secondary alcohol is used to make carboxylic acids, ketones are formed

53
Q

what are ketones?

A

C=O (carbonyl bond)

- ends in one

54
Q

what does carboxylic acid being described as a weak acid mean?

A

does not fully ionise

55
Q

neutralisation reaction where Ethnic acid reacts with sodium carbonate (Na2CO3)

A

CH3COONa, water and carbon dioxide form

56
Q

neutralisation reaction where ethnic acid reacts with sodium hydrogen carbonate (NaHCO3)

A

CH3COONa, water and CO2 gas form

57
Q

features of carboxylic acids

A
  • polar due to asymmetry and hydrogen bonding
  • soluble in water (dependent on length)
  • highest priority
58
Q

what are esters

A

synthetic flavours and fragrances

59
Q

how is an ester formed?

A

reacting an alcohol with a carboxylic acid in a condensation reaction (esterification reaction)
- H2SO4 as catalyst

60
Q

naming esters

A
  • end with oate

- alcohol becomes an ‘yl’

61
Q

formation of polyethene

A

addition polymerisation

ethene has bonds broken with UV and heat to form polyethene

62
Q

how are polymers named?

A

in honour of the alkene

63
Q

how is polyvinyl chloride formed?

A

vinyl chloride (CH2CHCl) has bonds broken with UV or heat and forms polyvinyl chloride

64
Q

how is poly amide formed?

A

nothing on arrow

65
Q

how is polystyrene formed?

A

styrene with UV and heat

- styrene has a benzene ring (C6H6) with one hydrogen lost

66
Q

how is polypropene formed?

A

propene with UV and heat

67
Q

polybutene

A

butene with UV and heat

68
Q

how is a polyester formed?

A

nothing on arrow

69
Q

what is covalent bonding?

A

the sharing of valence electrons between non-metal atoms so that each atom is able to acquire a full outershell

70
Q

what are permanent dipoles?

A

2 non-metal atoms which have an electronegative discrepancy form a bond. The pull on the bonding electron pair is favoured by the atom with a greater electronegativity. This discrepancy creates poles (changes) along the bond.

71
Q

what is hydrogen bonding?

A

a form of dipole-dipole bonding (inter) and dipole bond (intra)
-FONH

72
Q

what is a dispersion force?

A

intermolecular bond

  • weak
  • instantaneous dipole
73
Q

intermolecular bonds and their strength

A

strongest to weakest: H bond, dipole-dipole, dispersion

74
Q

How is an amide formed?

A

carboxylic acid and an amine react

  • water is condensed
  • amide link (C=O NH) also called peptide link
  • named ethyl ethanamide