1.5: Carbon Compounds - Organic chemistry introduction Flashcards
(93 cards)
1
Q
What is the function of carbon compounds?
A
providing energy in the form of carbohydrates and fats and making up large parts of proteins and DNA
2
Q
How are organic compounds obtained generally?
A
From crude oil or possibly coal derivatives and form a massively important range of compounds for fuels, plastics, solvents and pharmaceuticals.
3
Q
How do you name and draw an organic molecule?
A
By finding out which HOMOLOGOUS series it belongs to and to do this we must identify the FUNCTIONAL GROUP
4
Q
What is the Homologous series?
A
A group of molecules possessing the same functional group where each successive member of the series differs by - CH₂
5
Q
What is a functional group?
A
An atom or group of atoms which provide the characteristic chemical reactions of a molecule.
6
Q
What are the alkenes?
A
- part of the homologous series containing simplest organic compounds
- unsaturated hydrocarbons
7
Q
What is a hydrocarbon?
A
a compound containing Hydrogen and Carbon ONLY
8
Q
What do saturated alkenes contain?
A
only single bonds
9
Q
What is the general formula for hydrocarbons / alkenes?
A
CnH₂n+2
10
Q
What does the first part of the alkane name indicate?
A
The number of carbon atoms present in the longest carbon chain and is used when naming all organic compounds
11
Q
What does the second part of each alkane -an(e) indicate?
A
the presence of only single bonds
12
Q
What should you remember about carbon and hydrogen bonding?
A
- Carbon atoms always form 4 bonds
- hydrogen atoms always forms 1 bond
13
Q
What is molecular formula?
A
The actual number of atoms of each element in a compound
14
Q
What is the empirical formula?
A
The simplest whole number ratio of atoms of each element in a compound
15
Q
What is a structural formula?
A
The minimal detail required to show the arrangement of atoms
16
Q
What is a displayed formula?
A
It shows all atoms and all bonds
17
Q
What is the skeletal formula?
A
Shows the carbon skeleton and functional groups only
18
Q
What is the IUPAC rules?
A
international union of pure and applied chemistry, international agreement on naming of organic molecules
19
Q
How do you name compounds (simplified)
A
- find the longest chain of carbon atoms in molecule
- find the positions of any branches (alkyl groups) or functional groups on the chain
- give the positions of the functional groups then branches the lowest possible numbers
- use di, tri, tetra to indicate how many alkyl/functional groups there are
- if there is more than one alkyl group place the names alphabetically
20
Q
What is the name of the alkyl for CH₃- (alkyl chain formula)
A
Methyl-
21
Q
What is the name of the alkyl for C₂H₅ - (alkyl chain formula)
A
Ethyl -
22
Q
What is the name of the alkyl for C₃H₇- (alkyl chain formula)
A
Propyl-
23
Q
What is the functional group of alkene?
A
24
Q
What is an example of alkene?
A
CH₂= CHCH₂CH₃
25
What names are the alkene?
Ends in -ene but 1-ene
26
What is the functional groups of haloalkane?
- F
- Cl
- Br
- I
27
What is an example of a Haloalkane?
CH₃CH₂CH₂CH₂I
28
What are the names for haloalkane?
starts with
chloro-,
bromo-,
1 - iodobutane
29
What is the functional group of alcohol?
- OH
30
What is an example of an alcohol formula?
C₂H₅OH
31
What is the names for Alcohol
ends in -ol
Ethanol
32
What does aromatic mean in terms of organic compounds?
Organic compounds where some or all of the carbon atoms are found in a benzene ring
33
What does aliphatic mean in terms of organic compounds?
Organic compounds containing carbon and hydrogen in straight chains, branched chains or non-aromatic rings.
34
What does alicyclic mean in terms of organic compounds?
An aliphatic compound where some or all of the carbon atoms are joined together in non-aromatic ring/cyclic structures
35
How does isomerism occur?
When molecules with the same molecular formula have their atoms arranged in different ways
36
What are the two main types of isomerism?
- structural isomerism
- stereoisomerism
37
What is structural isomerism?
Structural isomers are compounds with the same molecular formula but different structural formula.
38
What is stereoisomerism?
Stereoisomerism are molecules that have the same structural formula but have a different spatial arrangement of atoms
39
What are the two types of stereoisomerism?
Geometrical isomerism and optical isomerism
40
When does geometric isomerism occur?
(E/Z and Cis/Trans)
occurs in molecules that possess...
a) double carbon bond which restricts rotation
b) each carbon in the double carbon bond (c=c) must be attached to two different atoms/groups.
41
What is E/Z isomerism?
identifying the highest priority group on each carbon in the double carbon bond.
HIGHEST PROTON NUMBER = HIGHEST PRIORITY GROUP
42
Where does the E isomer have the highest priority groups?
When the E isomer has the two highest priority groups on opposite sides.
43
Where does the Z isomer have the highest priority groups?
When the Z isomer has the two highest priority groups on the same side.
44
What is cis/trans isomerism?
Cis isomers have the same group on the same side.
Trans isomers have the same group on the opposite sides.
45
What doe cis-trans isomers always have?
E/Z isomers
46
What do not all E/Z isomers not have?
cis-trans isomers
47
What are alkanes?
saturated hydrocarbons
48
What does saturated mean?
means that there are only single bonds present
49
What does hydrocarbon mean?
Hydrocarbons only have hydrogen and carbon present
50
Are alkanes unreactive or reactive, why?
unreactive molecules due to the only single bonds of their bonds and the only single present which are not open to attack.
most reactions that take place involving charged particles, one of which will attack the polar end of the bond on the organic molecule
51
What does the bonding in alkanes involve?
only σ (sigma) bonding, this means the end-on overlap of atomic orbitals.
52
As the carbon chain length increase what happens to B.P?
the greater number of electrons,
- The more electrons, stronger London forces/induced dipole-dipole forces between molecules
- The more energy needed to overcome these forces of attraction
53
What is the b.p of structural isomers?
structural isomers with the same number of electrons
- the more branches lower the boiling point
- the molecules can not pack together as closely as there are less points of surface contact between molecules
- which results in weaker/fewer London forces which require less energy to overcome.
54
How are alkanes named?
using the IUPAC system, all end with -ane
55
what are alkanes mainly used for?
fuels because they release large amounts of energy when they burn
56
What are the products of complete combustion?
carbon dioxide and water
57
What is needed for complete combustion?
a good supply of oxygen
58
What products are produced in incomplete combustion?
carbon monoxide (poisonous / odourless gas), carbon particles (soot or smoke), water is always produced
59
What do alkanes have to react with?
highly reactive species due to alkanes being very unreactive. This is formed in the intense heat of a fire, in the form of reactive oxygen atoms
60
what is need for halogenation?
ultra-violet lights, provides the energy needed to break the covalent bonds.
(example of a photochemical reaction)
61
What is halogenation?
reaction with a halogen, chlorine, bromine or iodine
62
How does a photochemical reaction break?
By homolytic fission producing two halogen radicals
63
What is a photochemical reaction?
a chemical reaction initiated by the absorption of energy in the form of light.
64
What does radical mean?
A species with an unpaired electron (represent by a '.')
65
What is homiletic fission?
The breaking of a covalent bond, with each atom retaining one electron from the bond.
66
What do alkenes have?
double bond between two carbon atoms and so they are classified as unsaturated hydrocarbons
67
What are alkenes more reactive than alkanes?
due to the c=c bond which is electron-risk so attract positively - charged particles (known as electrophiles)
68
What is an electrophile?
electron pair acceptor eg H+, Cl+, ch3+
69
What do alkenes contain?
single σ (sigma) bonds between the carbon atoms and between carbon and hydrogen atoms
70
What is additionally between the carbon atoms in alkenes?
n (pi) bond which forms the second bond of the double bond.
71
what is a pi-bond caused by?
the side-on overlap of p-orbitals and is weaker than the sigma bond
72
What do alkenes produce when going through combustion?
alkenes burn similar to alkanes, producing carbon dioxide and water
73
What is a difference between alkenes and alkanes with combustion?
Alkenes tend not to burn as cleanly as alkanes,
producing more carbon (soot) and carbon monoxide (seen as an orange flame, rather than a blue flame)
74
What do alkenes also undergo?
Addition reactions
75
What is an addition reaction?
involves the breaking of π - bond and two new atoms or groups of atoms being added onto the molecule across the double bond. HETEROLYTIC FISSION
76
What is heterolytic fission?
when the covalent bond, (π - bond), breaks, one atom, keeps both electrons and ions are formed
77
What is the reagent used for reactions with hydrogen?
hydrogen gas
78
What is the condition needed in the reaction with hydrogen?
Nickel catalyst, high pressure
79
What reaction is used in manufacturing, same as hydrogenation?
manufacturing of hydrogenated vegetable oils to produce solid fats, used in the manufacture of margarines.
80
what reagent is used for the reaction with halogens?
Aqueous solution or halogen (e.g. bromine water)
81
What conditions are needed for the reaction with halogens?
Room temperature
82
What is the reaction with halogens called?
electrophilic addition.
83
What can electrophilic addition be used to distinguish and why?
distinguish between alkenes and alkanes as the alkanes will not react with the aqueous solution of the bromine but the alkene does react and so the orange/brown bromine water decolourises to colourless
84
What does reaction with hydrogen halides cause?
similar manner to the halogens, adding across the double bond to produce a haloalkane
85
what did Markovnikov observe?
when an unsymmetrical alkene reacts with an unsymmetrical addition molecule, one product was produced in preference to the other.
86
What is Markovnikov rule?
When a compound HX is added to an unsymmetrical alkene, the hydrogen becomes attached to the carbon with the most hydrogen attached to it already.
87
What is the reason for Markovnikov rule?
due to the stability of the carbocation (the intermediate)
88
How does stability increase per carbocation?
primary > secondary > tertiary
89
Why is the tertiary carbocation most stable?
Due to the presence of 3 carbon chains attached - all of which have positive inductive effect pushing electrons towards the positive carbon centre is stabilising the carbocation intermediate
90
What is the rule about carbocation stability?
'Hydrogen goes where most hydrogen is".
As the hydrogen adds onto the double bond first before the other atom.
91
What reagent occurs in the reaction with water?
steam
92
What conditions are needed in reactions with water?
phosphoric acid, 600K, 60atm
93
What occurs in the reaction with water?
The water is added across the double bond which forms an alcohol.
