4.1 basic organic chem Flashcards

1
Q

define nomenclature

A

system of naming compounds

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2
Q

what is a homologous series? give 3 examples

A

series fo substances with the same functional group and the successive members only differing by a CH₂ unit.

eg. alkanes, alkenes and alcohols

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3
Q

what is an alkane?

A

a saturated hydrocarbon

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4
Q

what is the alkane general formula?

A

CnH2n+2

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5
Q

name the first 10 alkanes

A

methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane

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6
Q

define an aliphatic hydrocarbon

A

a hydrocarbon in which carbon atoms are joined in a straight chain or branched chains

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7
Q

define an alicyclic hydrocarbon

A

a hydrocarbon that is an aliphatic compound arranged in non-aromatic rings with or without side chains
(no benzene rings, still ring structure)

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8
Q

define aromatic hydrocarbon

A

a compound with a benzene ring

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9
Q

define general formula

A

an algebraic formula that can generate any molecular formula in a family.

eg. CnH2n+2

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10
Q

define empirical formula

A

simplest whole number ratio of atoms of each element in a compound.

eg. C2H6 –> CH3

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11
Q

define molecular formula

A

the actual number of atoms of each element in a compound

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12
Q

define structural formula

A

the minimal detail that shows the arrangement of atoms in a molecule.

eg. CH3CH2CH2CH2OH

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13
Q

what is the displayed formula

A

the relative positioning of atoms and the bonds between them

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14
Q

define skeletal formula

A

the simplified organic formula shown by removing hydrogen atoms, leaving just carbon chains and alkyl chains, with the functional groups.

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15
Q

what is the general formula for alkyl groups?

A

CnH2n+1

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16
Q

what is the prefix of an alcohol?

A

hydroxyl-

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17
Q

what is the suffix of an alcohol?

A

-ol

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18
Q

what is the suffix of an aldehyde?

A

-al

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19
Q

what is the suffix of a carboxylic acid?

A

-oic acid

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20
Q

what are the prefixes of the first 4 haloalkanes?

A

fluoro-
chloro-
bromo-
iodo-

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21
Q

what is the suffix of ketones?

A

-one

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22
Q

define haloalkane

A

an alkane with a halogen attached to it

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23
Q

define structural isomer

A

compounds with the same molecular formulae but different structural formulae

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24
Q

what is the shape of an alkane molecule?

A

tetrahedral - 109.5 degrees

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25
Q

what kind of bonds are there in alkanes? define this term

A

sigma bonds - the overlap of orbitals between two atoms

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26
Q

in alkanes, what happens to boiling point as chain length increases? why?

A

as chain length increases boiling point increases - because there are more carbons - so more electrons - so stronger induced dipole-dipole interactions - more energy to break bonds.

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27
Q

in alkanes, what happens to boiling point after chains become very long?

A

boiling point levels off because the percentage increase of electrons become insignificant so the boiling doesn’t increase by that much.

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28
Q

how does a branched isomer effect the boiling point of an alkane?

A

branched isomers have lower boiling points - because straight chains have more surface contact - which means more induced dipole interactions.

branched isomers can’t get as close together so they have less interactions.

29
Q

state the word equation for the complete combustion of an alkane

A

alkane + oxygen –> carbon dioxide + water

30
Q

state the word equation for the incomplete combustion of an alkane

A

alkane + oxygen –> carbon monoxide + carbon dioxide + water

31
Q

define heterolytic fission

A

the breaking of a covalent bond in which one of the bonded elements receives all of the bond pair electrons, resulting in a positive an negative ion

32
Q

define homolytic fission

A

the breaking of a covalent bond in which each of the previously bonded atoms are given one electron each, resulting in two radicals

33
Q

define a radical

A

a species with an unpaired electron (that is highly reactive)

34
Q

what are the 3 steps of homolytic free radical substitution? describe them in terms of radicals present

A

initiation - in which 2 free radicals are formed

propagation - no. of radical doesn’t change. the reaction continues due to the continuous formation of radicals

termination - free radicals are consumed and react together

35
Q

example of homolytic free radical substitution:
making chloromethane from methane and chlorine.

  1. what is the balanced symbol equation?
A

CH₄ + Cl➝ HCl + CHCl

36
Q

example of homolytic free radical substitution:
making chloromethane from methane and chlorine.

  1. what happens in the initiation step? what is needed for this step? give the equation for it
A

initiation: UV light is needed to break the chlorine bond to create two chlorine radicals.

Cl₂ ➝ Cl• + Cl•

37
Q

example of homolytic free radical substitution:
making chloromethane from methane and chlorine.

  1. what happens in the propagation step? give the equations for it
A

propagation: radicals are used then regenerated, creating a chain reaction.

Cl• + CH₄ ➝ CH₃• + HCl

Cl₂ + CH₃• ➝ CH₃Cl + Cl•

38
Q

example of homolytic free radical substitution:
making chloromethane from methane and chlorine.

  1. what happens in the termination step? write 3 equations of how the reaction could come to this
A

termination: reaction stops because the radicals react together, removing themselves

Cl• + Cl• ➝ Cl₂

Cl• + CH₃• ➝ CH₃Cl

CH₃• + CH₃• ➝ C₂H₆

39
Q

what shape do alkenes have? what bond angle? why?

A

trigonal planar - 120 degrees

because the sigma and pi bonds repel by equal amounts so create angles of 120 degrees (I think..?)

40
Q

define sigma bond

A

overlap of orbitals between 2 atoms

41
Q

define pi bond

A

overlap of p-orbitals above and below atoms -creates double bond in alkenes

42
Q

what is an addition reaction?

A

when something is added to a species, creating only ONE product

43
Q

alkene + hydrogen =? what is needed for the reaction?

A

alkane - nickel catalyst

44
Q

alkene + water =? what is needed for the reaction?

A

alcohol - water must be steam and a phosphoric acid catalyst

45
Q

define electrophile

A

something that accepts electrons

46
Q

outline the three main steps of electrophilic addition of alkenes

A
  1. C=C electrons are accepted by electrophile and one bond is created
  2. a carbocation is formed and the lone electrons from the left over electrophile attract to it (intermediate)
  3. saturated substance is formed.
47
Q

electrophilic addition: what three typed of carbocations can be formed? which is more stable?

A

primary: carbocation only bonded to ONE other carbon
secondary: carbocation bonded to TWO other carbons
tertiary: carbocation bonded to THREE other carbons

TERTIARY is more stable

48
Q

electrophilic addition: how is the major product decided?

A

the most stable = the major product

49
Q

define stereoisomerism

A

compounds with the same structural formula but different arrangement in space

50
Q

what must an alkene have for there to be stereoisomerism?

A

each carbon in the C=C must have two distinct groups bonded EACH

if one carbon has two of the same group, there is no stereoisomerism

51
Q

why can alkenes have stereoisomerism?

A

because the double bond restricts rotation

52
Q

name two methods of identifying stereoisomers

A

cis-trans

E-Z

53
Q

when would you use cis-trans methods?

A

when each of the two groups in question that are bonded to each carbon are the same

54
Q

what would a cis alkene look like?

A

two groups on the SAME side of the C=C

55
Q

what would a trans alkene look like?

A

two groups on OPPOSITE sides of the C=C

56
Q

how do you decide whether an alkene is E or Z?

A

split the alkene in half
decide which is the high priority group
see whether they are on the same side or opposite sides.

57
Q

what is considered a high priority group?

A

groups with the highest Mr

58
Q

what would an E alkene look like?

A

two highest priority groups are on opposite sides

E for Enemies

59
Q

what would a Z alkene look like?

A

two highest priority groups on the same side

Z for Zee Zame Zide

60
Q

define polymerisation

A

monomers reacting together to make a polymer - repeated chain

61
Q

how are monomers and polymers drawn in a polymerisation equation?

A

both with brackets with an ‘n’ outside representing number of units

polymer has extra bonds continued out the brackets

62
Q

why can’t addition polymers be broken down in the environment?

A

because they are:
- saturated
- very stable
so bonds aren’t broken easily

63
Q

suggest 6 ways of disposing of polymers

A
organic feedstock 
biodegradable 
combustion
landfill 
photodegradable 
recycling
64
Q

name 2 positives and 1 negative of using combustion to dispose of polymers

A

positives:

  1. produces heat which can generate electricity
  2. greenhouse gases (below) can be avoided using alkali scrubbers

negative:
1. CO2 is produced = greenhouse gas, and HCl gas is produced from burning Cl based compounds

65
Q

how do you make a polymer biodegradable?

A

mixing plant based polymers with regular polymers to help them break down in the earth

66
Q

what is photodegradable?

A

something that can be broken down by light

bonds are weakened by the absorption of light

67
Q

how do you make a polymer photodegradable?

A

mixing photodegradable substances into the regular polymers

68
Q

what is one problem with photodegradable polymers?

A

photodegradable polymers in landfill may not receive enough sunlight if they are buried in rubbish = not break down