Module 4 flashcards
0.0 / 5
- Created by: izzking
- Created on: 28-05-24 16:22
what is general formula?
the simplest algebraic formula of a member of a homologous series
1 of 115
what is structural formula?
the simplest way to show the arrangement of atoms in a molecule
2 of 115
what is displayed formula?
the relative positioning of atoms and the bonds between them
3 of 115
what is skeletal formula?
simplified organic formula only showing carbon skeleton and associated functional groups (hydrogen atoms removed from alkyl chain)
4 of 115
what is a homologous series?
a series of organic compounds with the same functional group whereby each successive member differs by CH2
5 of 115
what is a functional group?
a group of atoms responsible for the characteristic reactions of a compound
6 of 115
what is an aliphatic compound?
compound containing carbon and hydrogen bonded in straight chains, branched chains or non-aromatic rings
7 of 115
what is an alicyclic compound?
compound containing carbon and hydrogen bonded in non-aromatic rings with or without side-chains
8 of 115
what is an aromatic compound?
compound containing a benzene ring
9 of 115
what is a saturated compound?
single C-C bonds only
10 of 115
what is an unsaturated compound?
presence of multiple C-C bond (double, triple)
11 of 115
what is a structural isomer?
compounds with the same molecular formula but different structural formula
12 of 115
what is homolytic fission?
the breaking of a covalent bond whereby each bonding atom receives one electron from the bonded pair, forming two radicals
13 of 115
what is heterolytic fission?
the breaking of a covalent whereby one bonding atoms receives both electrons from the bonding pair, forming a cation and anion
14 of 115
what is a radical?
a species with an unpaired electron
15 of 115
what is a curly arrow?
displays the movement of a pair of electrons in a reaction mechanism, either heterolytic fission or the formation of a covalent bond
16 of 115
what is a dipole?
a partial charge shown by delta +/-
17 of 115
what is an alkane?
a saturated hydrocarbon
18 of 115
what is the shape and bond angle around a central C atom in an alkane?
tetrahedral
109.5
109.5
19 of 115
what covalent bond is present in C-C bonds?
a sigma bond
20 of 115
how is a sigma bond formed?
direct overlap of orbitals containing one electron between the bonding atoms
21 of 115
why do longer chain alkanes have higher boiling points?
longer carbon chain means more surface area contact between molecules so greater induced dipole-dipole forces so more energy required to break London forces
22 of 115
why do less branched alkanes have higher boiling points?
less branching means more surface area points of contact so greater Induced dipole-dipole forces that require more energy to be broken. straight chain molecules can be closer together, increasing contact and London forces
23 of 115
why do alkanes have a low reactivity?
C-C and C-H bonds have a high enthalpy
C-C bonds are non-polar
C-H bonds are considered non-polar (similar electronegativity)
C-C bonds are non-polar
C-H bonds are considered non-polar (similar electronegativity)
24 of 115
why are alkanes used as fuels
combust completely in a plentiful supply of oxygen to produce CO2 + H2O
readily available, cheap to transport
no toxic products
readily available, cheap to transport
no toxic products
25 of 115
complete combustion
alkane + O2 -> CO2 +H20
26 of 115
incomplete combustion
limited supply of oxygen
alkane + O2 -> CO + H2O
alkane + O2 -> C + H2O
alkane + O2 -> CO + H2O
alkane + O2 -> C + H2O
27 of 115
what are the dangers of CO?
toxic gas
odourless
binds to haemoglobin
odourless
binds to haemoglobin
28 of 115
what is the mechanism for the halogenation of alkanes?
free radical substitution
29 of 115
what are the 3 stages of free radical substitution?
initiation, propagation, termination
0->2, 1->1, 2->0 (no of radicals)
0->2, 1->1, 2->0 (no of radicals)
30 of 115
what is needed for the initiation step?
UV light to break the covalent bond in Cl2 or Br2 by homolytic fission
31 of 115
what are the limitations of radical substitution in organic synthesis?
further substitution occurs with an excess of halogen radicals
substitution can occur at different positions in a carbon chain, forming structural isomers
substitution can occur at different positions in a carbon chain, forming structural isomers
32 of 115
what is an alkene?
an unsaturated hydrocarbon
33 of 115
what shape and bond angle does a central C atom have?
trigonal planar
3 bonding regions of equal electron density and repulsion
120
3 bonding regions of equal electron density and repulsion
120
34 of 115
what does a double bond consist of?
a sigma bond and a pi bond
35 of 115
how is a pi bond formed?
sideways overlap of 2 p-orbitals containing 1 electron
electron density is concentrated above and below the plane of the carbon atoms
electron density is concentrated above and below the plane of the carbon atoms
36 of 115
what is a stereoisomer?
compounds with the same structural formula but with a different arrangement in space
37 of 115
what is an E/Z isomerism?
restricted rotation around a double bond and two different groups attached to each carbon atom of the C=C
38 of 115
what is a cis/trans isomerism?
special case of E/Z isomerism where one of the groups attached to each carbon atom of the C=C are the same.
39 of 115
how are cahn-ingold-prelog rules used?
can identify E/Z isomers by assigning priority to groups
higher atomic number= higher priority
higher priority groups on same side= Z
higher priority groups diagonally placed=E
higher atomic number= higher priority
higher priority groups on same side= Z
higher priority groups diagonally placed=E
40 of 115
why are alkenes more reactive than alkanes?
the pi bond is weaker than the sigma bond, is more exposed and is therefore broken more readily
41 of 115
what is hydrogenation of alkenes and what are reactants/conditions?
addition reaction to form an alkane
hydrogen
Nickel catalyst
423K
hydrogen
Nickel catalyst
423K
42 of 115
what is halogenation of alkenes and what are reactants/conditions?
addition reaction to form dihaloalkanes
Cl/Br or HCl/HBr
RTP
Cl/Br or HCl/HBr
RTP
43 of 115
how can you test for unsaturation?
bromine water will be decolourised from orange to colourless by a C=C bond
44 of 115
what is hydration of alkenes and what are reactants/conditions?
addition reaction to form alcohols
steam
H3PO4 or H2SO4 catalyst
steam
H3PO4 or H2SO4 catalyst
45 of 115
what is an electrophile?
an electron pair acceptor attracted to an area of high electron density
positive ion or delta+ molecule
positive ion or delta+ molecule
46 of 115
why is a double bond an area of high electron density?
presence of pi bonds attracts electrophiles
47 of 115
how can an induced dipole form in the mechanism for halogenation?
the high electron density of the double bond can polarise the X-X bond
H-X bond is already polar
H-X bond is already polar
48 of 115
why is Markownikoff's rule used?
to determine the yield of an organic product formed in addition reactions of H-X to unsymmetrical alkenes
49 of 115
what is a primary carbocation?
positive charge on a carbon atom is on a carbon that is attached to only one other carbon (end chain carbon)
50 of 115
what is a secondary carbocation?
positive charge on a carbon atom is on a carbon that is attached to two other carbons
51 of 115
what is a tertiary carbocation?
positive charge on a carbon atom is on a carbon that is attached to 3 other carbons
52 of 115
what carbon will the hydrogen atom of the hydrogen halide attach to?
the carbon with the most H atoms attached/ least R groups
53 of 115
what carbon will the halogen atom of the hydrogen halide attach to?
the carbon with the least H atoms attached/ most R groups
54 of 115
what is a major product?
product with higher yield
formed via a more stable carbocation
formed via a more stable carbocation
55 of 115
what is a minor product?
product with a lower yield formed via a less stable carbocation
56 of 115
why does stability increase from primary to tertiary carbocation
carbon atom have a stronger electron donating ability than hydrogen atoms
positive charge is spread over the alkyl groups
positive charge is spread over the alkyl groups
57 of 115
what is addition polymerisation?
addition of unsaturated alkene monomers to form long saturated polymer chains
58 of 115
what are the uses of poly(ethene)?
plastic bags
toys
shampoo bottles
toys
shampoo bottles
59 of 115
what are the uses of poly(chloroethene)/PVC?
pipes
films and sheeting
bottles
films and sheeting
bottles
60 of 115
what are the uses of poly(styrene)?
packaging materials
cups
cups
61 of 115
what are the uses of poly(tetrafluoroethene)/Teflon)?
non-stick pan coating
62 of 115
how is recycling polymers sustainable?
conserves finite fossil fuels
decreases waste in landfill
polymers are sorted, chopped, washed, dried and melted into pellets
decreases waste in landfill
polymers are sorted, chopped, washed, dried and melted into pellets
63 of 115
how is disposal and recycling of PVC hazardous?
when burnt corrosive HCl gas is released as well as toxic dioxins
64 of 115
how is the removal of toxic waste products sustainable?
prevents release of toxic by-products
solvents used to dissole PVC and precipitation to recover high grade PVC
solvents used to dissole PVC and precipitation to recover high grade PVC
65 of 115
how is combustion of polymers sustainable?
energy production conserves finite fossil fuels
polymers have a high stored energy value
polymers have a high stored energy value
66 of 115
how is feedstock recycling sustainable?
organic feedstock for the production of new polymers, plastics and other organic compounds
able to handle unsorted and unwashed polymers
able to handle unsorted and unwashed polymers
67 of 115
what are biodegradable polymers?
polymers that can be broken down by microorganisms
68 of 115
what are photodegradable polymers?
polymers containing bonds that are broken by absorbing light
69 of 115
why are alcohols less volatile and have a higher boiling point than their corresponding alkanes?
alcohols have hydrogen bonds between molecules that require more energy than the London forces in alkanes
70 of 115
why are alcohols more soluble in water than alkanes
alcohols have a polar O-H bond meaning it can form hydrogen bonds with water molecules
alkanes are non-polar so cannot form hydrogen bonding
alkanes are non-polar so cannot form hydrogen bonding
71 of 115
why does alcohol solubility decrease as chain length increases?
the influence of the O-H group becomes relatively smaller
72 of 115
what is a primary alcohol?
alcohol with -OH group attached to carbon that is bonded to one other R group
73 of 115
what is a secondary alcohol?
alcohol with -OH group attached to carbon that is bonded to two other R groups
74 of 115
what is a tertiary alcohol?
alcohol with -OH group attached to carbon that is bonded to 3 other R groups
75 of 115
what is the combustion of alcohols?
combust completely in a plentiful supply of oxygen to produce CO2 + H2O
as chain increases energy released increases
as chain increases energy released increases
76 of 115
what reagent is used to oxidise alcohols?
K2Cr2O7/H2SO4
acidified potassium dichromate
acidified potassium dichromate
77 of 115
what is the colour change present if an alcohol is oxidised by K2Cr2O7/H2SO4?
orange to green
78 of 115
how can aldehydes be prepared from alcohols?
oxidation of a primary alcohol
K2Cr2O7/H2SO4
distillation
K2Cr2O7/H2SO4
distillation
79 of 115
how can carboxylic acids be prepared from alcohols?
oxidation of a primary alcohol
K2Cr2O7/H2SO4
reflux
2[O]
K2Cr2O7/H2SO4
reflux
2[O]
80 of 115
how can ketones be prepared from alcohols?
oxidation of a secondary alcohol
K2Cr2O7/H2SO4
reflux
K2Cr2O7/H2SO4
reflux
81 of 115
what happens when K2Cr2O7/H2SO4 is added to a tertiary alcohol
nothing as tertiary alcohols can't be oxidised
solution remains orange
solution remains orange
82 of 115
how can alkenes be prepared from alcohols and what conditions are needed?
elimination of H20
dehydration
heat
H3PO4 OR H2SO4 catalyst
dehydration
heat
H3PO4 OR H2SO4 catalyst
83 of 115
how can haloalkanes by prepared from alcohols and what reagents are needed?
substitution reaction
NaBr + H2SO4 -> HBr
heat by reflux
forms haloalkane + NaHSO4 + H2O
NaBr + H2SO4 -> HBr
heat by reflux
forms haloalkane + NaHSO4 + H2O
84 of 115
why is a C-X bond polar?
halogen atoms are more electronegative than carbon atoms
85 of 115
what is a nucleophile?
and electron pair donor
attracted to an area of low electron density/ electron deficient carbon
attracted to an area of low electron density/ electron deficient carbon
86 of 115
how are haloalkanes hydrolysed?
nucleophilic substitution
NaOH or water
reflux
OH displaces X
NaOH or water
reflux
OH displaces X
87 of 115
how can the rate of hydrolysis of primary haloalkanes be tested?
rate of precipitate formation
ethanol
AgNO3
ethanol
AgNO3
88 of 115
why does the rate of hydrolysis of primary haloalkanes differ?
rate of hydrolysis increases as C-X bond strength/enthalpy decreases
carbocation stability: tertiary fastest, primary slowest
carbocation stability: tertiary fastest, primary slowest
89 of 115
how is ozone broken down and produced in the stratosphere?
equilibrium reaction
UV
02 + 0. <-> O3
UV
02 + 0. <-> O3
90 of 115
How are Halogen radicals formed in the stratosphere?
stability allows them to not react until sufficient UV energy is present
The C-Cl bond is broken by homolytic fission
CF2Cl2 -> CF2Cl. + Cl.
The C-Cl bond is broken by homolytic fission
CF2Cl2 -> CF2Cl. + Cl.
91 of 115
How does the reactive Cl. break down ozone?
acts as a catalyst
92 of 115
what are the propagation steps and overall reaction of the breakdown of ozone?
Cl. + O3 -> ClO.+ O2
ClO. + O -> O2 + Cl.
Cl. + O3 -> 2(O2)
ClO. + O -> O2 + Cl.
Cl. + O3 -> 2(O2)
93 of 115
what other radical can catalyse the breakdown of O3?
NO.
94 of 115
how are NO. formed?
lightning strikes
aircraft in stratosphere
aircraft in stratosphere
95 of 115
how is a separating funnel used?
aq and organic layer separated as they have different densities
96 of 115
how are impure products dried?
addition of an anhydrous salt/ drying agent until dispersed as a fine powder
97 of 115
what are some examples of drying agents?
MgSO4, CaSO4, CaCl2
98 of 115
how is redistillation carried out?
set up distillation apparatus and redistill, collecting the product with the boiling point of the desired compound
99 of 115
what is the functional group of an amine?
-NH2
100 of 115
what is the functional group of an acyl chloride?
C=O
|
Cl
|
Cl
101 of 115
what is the functional group of a nitrile?
-CN
102 of 115
what is a target molecule?
the compound being prepared by organic synthesis
103 of 115
what is an intermediate in terms of two stage synthesis?
compound that links the starting and target molecules
104 of 115
what does the molecular ion pea tell us?
molar mass of compound
105 of 115
what is fragmentation?
breakdown of of molecular ions into a smaller fragment ion and a radical
106 of 115
what fragment ion has a m/z value of 15?
CH3+
107 of 115
what fragment ion has a m/z value of 29?
C2H5+
108 of 115
what fragment ion has a m/z value of 43?
C3H7+
109 of 115
what fragment ion has a m/z value of 57?
C4H9+
110 of 115
how can you calculate the number of carbon atoms in a compound?
height of M+1 peak
______________________x100
height of M peak
______________________x100
height of M peak
111 of 115
what affect does IR have on covalent bonds?
IR causes covalent bonds to vibrate more and stretch more as they absorb energy
112 of 115
what frequency of radiation can a covalent bond absorb?
same frequency as natural bond frequency
113 of 115
what is the effect of IR on atmospheric gases and the environment?
CO2, H2O AND CH4 can absorb longer wavelength IR and re-emit it as radiation that causes global warming
114 of 115
what are the uses of IR spectroscopy?
identifying functional groups
monitoring gases that cause air pollution: CO NO
breathalysers to identify ethanol
monitoring gases that cause air pollution: CO NO
breathalysers to identify ethanol
115 of 115
Other cards in this set
Card 2
Front
what is structural formula?
Back
the simplest way to show the arrangement of atoms in a molecule
Card 3
Front
what is displayed formula?
Back
Card 4
Front
what is skeletal formula?
Back
Card 5
Front
what is a homologous series?
Back
Similar Chemistry resources:
0.0 / 5
0.0 / 5
0.0 / 5
0.0 / 5
0.0 / 5
0.0 / 5
3.0 / 5 based on 1 rating
3.0 / 5 based on 1 rating
4.5 / 5 based on 4 ratings
0.0 / 5
Comments
No comments have yet been made