Organic chem - 1 Flashcards
(166 cards)
1
Q
Define organic chemistry
A
Organic chemistry is the study of carbon based compounds.
2
Q
Why is organic chemistry very important?
A
Industrially, produces billions of euro, necessary for the production of pharmaceuticals, petrol, diesel etc.
3
Q
Name the three important homologous series
A
- Alkanes
- Alkenes
- Alkynes
4
Q
How many bonds can carbon form?
A
4 because it has a valency of 4 & is in group 4
5
Q
What can carbon bonds comprise of?
A
a) . 4 single bonds - saturated. (4 bonding pairs; no lone pairs - tetrahedral)
b) . 1 double bond & 2 single bonds - unsaturated. (3 bonding pairs; no lone pairs - planar)
c) . 1 triple bond & 1 single bond - unsaturated. (2 bonding pairs; no lone pairs - planar)
6
Q
Define saturated
A
Contains only single bonds around carbon atoms.
7
Q
Define unsaturated
A
Contains a multiple bond between two carbon atoms.
8
Q
Define hydrocarbon
A
A hydrocarbon is a compound that consists of the elements carbon and hydrogen.
9
Q
What are hydrocarbons formed by?
A
Formed by the decomposition of animal waste and vegetation.
10
Q
Define aliphatic hydrocarbons
A
Aliphatic hydrocarbons are straight or branched-chained hydrocarbon molecules.
11
Q
Define aromatic hydrocarbons
A
Aromatic hydrocarbons are hydrocarbons that contain a ‘ring’ in their structure i.e a benzene ring.
12
Q
Name 3 sources of hydrocarbons
A
- Coal
- Natural gas (methane)
- Petroleum (crude oil)
13
Q
Describe coal as a hydrocarbon
A
- Coal is a black solid that contains mainly carbon.
- Burning coal causes air pollution.
14
Q
Describe natural gas (methane) as a hydrocarbon
A
- It is produced when dead organic material is converted into hydrocarbon molecules over millions of years.
- Found in slurry pits , coal mines, intestinal bacteria of cows and sheep and rubbish dumps.
- Kinsale gas = 95% methane which contributes to the greenhouse effect.
15
Q
Describe crude oil as a hydrocarbon
A
- Consists of many aliphatic and aromatic hydrocarbons.
Used to make drugs, plastics, cosmetics, petrol etc.
Most sought after resource.
Thick black substance - but useless in that form.
16
Q
What is the biggest source of hydrocarbons?
A
Petroleum (crude oil)
17
Q
What are hydrocarbons
A
Fuels i.e they release energy when burned in oxygen.
18
Q
What is the number of carbons in ‘Meth’
A
1
19
Q
What is the number of carbons in ‘Eth’
A
2
20
Q
What is the number of carbons in ‘Prop’
A
3
21
Q
What is the number of carbons in ‘But’
A
4
22
Q
What is the number of carbons in ‘Pent’
A
5
23
Q
What is the number of carbons in ‘Hex’
A
6
24
Q
What is the number of carbons in ‘Hept’
A
7
25
What is the number of carbons in 'Oct'
8
26
What type of bonds do alkanes have around/between them?
Single bonds around/between the carbon atoms
27
Are alkanes saturated or unsaturated compounds?
Saturated compounds
28
What do the names of alkane molecules end in
- ane i.e methane, ethane, propane
29
What are C1-C4 at room temperature?
Gases
30
What are C5-C16 at room temperature?
Liquids
31
What are C17 + at room temperature?
Waxy solids
32
What force of attraction do Alkanes have?
Weak Van der Waals forces of attraction
33
Why/When does the boiling point increase
With increasing chain length as greater surface contact between molecules means greater numbers of Van der Waals forces between the molecules.
34
What does each successive member of the alkanes differ by?
CH₂
35
Are alkanes soluble or insoluble in water?
Insoluble
36
Why are alkanes insoluble in water?
As they are non-polar molecules (tetrahedral shape) and do not form hydrogen bonds with water.
37
Are alkanes soluble or insoluble in non-polar solvents such as cyclohexane or chloroform?
Soluble
38
Why is ethane a good fuel?
As it is unreactive (unreactive because of the fact that they are saturated)
39
What are the two diagnostic tests proving that alkanes are saturated compounds?
- saturated -> unreactive, alkanes do not decolourise bromine water from red/brown to colourless or a dilute solution of potassium manganate (VII) from purple to colourless.
40
What type of reactions do alkanes usually undergo?
Free radical substitution
41
What is free radical substitution?
When an atom or group of atoms are replaced by another atom or group of atoms. Two main products are produced, one organic and one inorganic.
42
What is an organic compound?
Any large class of chemical compounds in which one or more atoms of carbon are covalently linked to atoms of other elements, most commonly H, O or N.
43
In the combustion : CH4 +Cl2 --> CH3Cl + HCl , what is the re-agent , the condition and the organic product
- re-agent = Cl
- the condition = uv light
- organic product = cloro methane
44
What are conditions?
Conditions are things that need to be present for a reaction to happen.
45
Can every organic molecule undergo combustion?
Yes
46
What shape are all alkanes?
Tetrahedral
47
Why are all alkanes tetrahedral?
Due to the presence of four bonding pairs and no lone pairs around the carbon atom.
48
What are the 4 IUPAC system rules?
1. The longest chain carbon is the parent alkane.
2. The alkane is named from whichever direction gives the lowest number to the carbon atom to which the groups are attached.
3. The substituted groups are then named and numbered alphabetically i.e bromo before chloro, ethyl before methyl etc.
4. If there are two of the same group on the molecule then the prefix 'di' is placed before the groups name i.e dimethyl. If there are three of the same group then 'tri' is used and four, tetra.
49
What is the combustion of methane?
Ch4 + 2O₂ --> CO₂ +2H₂O
50
What is the combustion of Ethanol?
C₂H5OH +3O2 --> 2CO₂ +3H₂O
51
What is the combustion of propanoic acid?
C₂H5COOH + 3.5O₂ --> 3CO₂ +3H₂O
52
What is the combustion formula?
Organic compound + O₂ --> CO₂ + H₂0 + energy
53
What are alkyl groups?
The alkane missing one of its hydrogens
54
Name 2 alkyl groups?
CH₃ - Methyl
| C₂H5 - Ethyl
55
What happens if you put an alkyl group on the first carbon of a molecule?
It is simply an extension of the chain.
56
What do you get if you put a methyl group on the first carbon of propane ?
You get butane
57
Does 1-methylpropane exist?
NO - its butane
58
Define structural isomers
Structural isomers are molecules with the same molecular formulas but different structural formulas. (Different names but the same number and type of atoms)
59
How many isomers of C5H12 are there? Give there names and structural formulae.
3 isomers:
- Pentane
- 2 methylbutane
- 2,2 dimethylpropane
60
Define a homologous series
A homologous series is a group of compounds, all members of the group contain the same functional group and successive members differ by CH2.
61
Define a functional group
A functional group is a group of atoms upon which the characteristic properties of a homologous series depends.
62
What type of bonds are between alkenes?
All members of alkenes contain one double bond between two of the carbon atoms.
63
Are alkenes saturated or unsaturated?
Unsaturated
64
Why are alkenes unsaturated?
They are unsaturated as they contain a multiple bond between two carbon atoms.
65
(alkenes) C2 --> C4 are …..
Gases
66
(alkenes) C5 --> C16 are ……..
Liquids
67
(alkenes) C17 + are …...
Waxy solids
68
What are the alkenes held together by?
They are held together by weak Van der Waal forces of attraction.
69
When do boiling points increase?
Boiling points increase with increasing chain length due to increases surface contact between molecules and more Van der Waals forces.
70
What does each successive member of the alkenes differ by?
CH₂
71
Are alkenes insoluble or soluble in polar solvents such as water?
Insoluble
72
Why are alkenes insoluble in polar solvents such as water?
As they do not form hydrogen bonds with water as they are non-polar.
73
Name two non-polar solvents that alkenes are soluble in.
Chloroform and cyclohexane
74
Are alkenes reactive or unreactive?
Reactive
75
Why are alkenes reactive?
They are reactive as they are unsaturated
76
What are the two tests that prove unsaturation?
Because they are unsaturated they are reactive; alkenes will decolourise bromine water from red/brown to colourless or a dilute solution of potassium manganate (VII) from purple to colourless.
77
What type of reactions do alkenes typically undergo?
Ionic addition reactions
78
What happens in ionic addition reactions?
The double bond between carbon atoms will become single, the molecule that adds on splits in two and each part adds on to a carbon that was on either side of the double bond. One main product is produced.
79
What is the first member of the alkenes and why?
Ethene, as you must have two carbons in the molecule to have a double bond between the carbons.
80
What do the names of alkene end in?
Ene i.e ethene, propene etc.
81
What are but-1-ene and but-2-ene?
Structural isomers of eachother.
82
What does the number in the middle of the name give?
The position of the double bond.
83
How do you determine the direction when naming substituted alkene molecules?
We must name in the direction that gives the lowest possible number to the position of the double bond. Once this has been decided the molecule must be named in this direction only.
84
What happens if you put an alkyl group on the first carbon of an alkene?
It is simply an extension of the chain
85
What type of bond do all members of the alkynes have?
All members of the alkynes have a triple bond between two of the carbon atoms.
86
Are alkynes saturated or unsaturated?
Unsaturated
87
What do the names of the alkynes end ?
yne i.e ethyne, propyne
88
Is ethyne a gas, a liquid or a solid?
A gas
89
What does each successive member of the alkynes differ by?
CH₂
90
Are alkynes soluble or insoluble in water?
Insoluble
91
Are alkynes polar or non-polar?
Non-polar
92
What are alkynes insoluble in water?
As they are non-polar and they do not form hydrogen bonds with water
93
What are 2 solvents that alkynes are soluble in?
They are soluble in non-polar solvents such as chloroform or cyclohexane.
94
What proves that alkynes are unsaturated?
They are unsaturated and hence decolourise bromine water from red/brown to colourless or a dilute solution of potassium manganate (VII) from purple to colourless thus proving that they are unsaturated.
95
What type of reactions do alkynes typically undergo?
Addition reactions
96
What is the common name for ethyne?
Acetylene
97
What is ethyne/acetylene used for?
It is used for cutting and welding metals in the form of oxyacetylene as when ethyne is burned in oxygen it reaches temperatures of over 3000C
98
Why is alkyne unsaturated?
It is unsaturated as it has a triple bond between twon carbons.
99
Define aromatic hydrocarbons
Aromatic hydrocarbons have a benzene ring in their structure
100
Who discovered benzene?
Faraday in the early 1800's.
101
Is benzene saturated or unsaturated? And what is it's formula?
It is a highly unsaturated compound. It's formula is C6H6.
102
Due to its unsaturation it was expected to undergo addition reactions but was unexpectedly found to be unreactive. Why?
Benzene does not have a double or single bonds between the carbons as was originally thought. The length of the carbon-carbon bond in benzene was found to be intermediate length between a single and a double bond. This makes benzene stable and unreactive.
103
Is benzene soluble or insoluble in polar water?
Insoluble
104
What shape is benzene?
The molecule is hexagonal planar and all bond angles are 120°
105
Why is benzene bad for you?
As benzene is carcinogenic and toxic.
106
Discuss the reaction
Benzene does not decolourise bromine water or dilute potassium manganate (VII) solution.
107
What is used in preference to benzene in the lab and why?
Methylbenzene is used in preference to benzene in the lab as benzene is toxic and carcinogenic. Methylbenzene is also a good organic solvent.
108
What are the three social and applied aspects of aromatic hydrocarbons?
1. Used as solvents in the paints industry.
2. Form the basis of pharmaceuticals, detergents, dyes and herbicides.
3. Care must be taken as are carcinogenic.
109
Write a balanced equation of ethane.
2 C2H6 + 7 O₂ → 4 CO₂ + 6 H₂O
110
Write a balanced equation of propene.
C₃H8 + 5O₂ ---> 3CO₂ + 4H₂O
111
Calculate the percentage carbon, by mass, in methylbenzene?
C7H8
7C = 7(12) = 84
Mr = 7(12) + 8(1) = 92
84/92 x 100/1 = 91.3%
112
Draw methane and say its molecular formula
- In copy
- CH4
- 2 tetrahedral carbons
113
Draw ethane and say its molecular formula
- In copy
| - C₃H8
114
Draw butane and say its molecular formula
- In copy
| - C4H10
115
Draw 2 chlorobutane and say its molecular formula
- In copy
| - Not a pure alkane
116
Draw 1,2 dichloropropane and say its molecular formula
- In copy
117
Draw 3 bromo - 1 chlorobutane and say its molecular formula
- In copy
118
Draw 2,2 dibromo - 3 chlorobutane
- In copy
119
Draw 2 methylbutane
- In copy
120
Draw 1 bromo - 4 chloro - 3 methylpentane
- In copy
121
Draw Pentane
- In copy
122
Draw ethene and say its molecular formula
- In copy
- C₂H4
- 3 bonding pairs
- Trigonal planar
123
Draw propene and say its molecular formula
- In copy
| - C3H6
124
Draw But - 1 - ene and say its molecular formula
- In copy
| - C4H8
125
Draw But - 2 - ene and say its molecular formula
- In copy
| - C4H8
126
Draw 3 bromo - but - 1 - ene
- In copy
127
What decides the direction ?
The double bond
128
What must the chain of carbons include
- The double bond
129
Draw 3 methylbut - 1 - ene and say its molecular formula
- In copy
- C5H10
- 2 planar carbon's
- 3 tetrahedral carbon's
130
Draw ethyne and say its molecular formula and describe it
- In copy
- C₂H₂
- Smallest alkyne
- 2 planar carbons
- small & light = gas at r.t
131
Are alcohol hydrocarbons?
NO
132
What group is alcohol from?
Hydroxyl group
133
Draw methanol and say its molecular formula
- In copy
| - CH3OH
134
What is the smallest alcohol
Methanol
135
What does methanol effect?
Optic nerve = permanent affect with large possibility of permanent blindness
136
What has a higher boiling point, methane or methanol?
Methanol
137
What determines the direction in alcohols?
The OH
138
Draw ethanol and say its molecular formula
- In copy
- C₂H5OH
- Alcohol found in drinks
139
Draw propan - 1 - ol and say its molecular formula
- In copy
| - C₃H7OH
140
Draw propan - 2 - ol and say its molecular formula and state what type of alcohol it is
- In copy
- C₃H7OH
- Secondary alcohol
141
Draw propan - 3 - ol and say its molecular formula and state what type of alcohol it is
- In copy
- C₃H7OH
- Secondary alcohol
142
Draw 2 methylpentan - 2 - ol and state what type of alcohol it is
- In copy
- tertiary alcohol
- non polar carbon chain
- polar OH group
143
Draw butan - 1 - ol and state what type of alcohol it is
- In copy
| - Primary alcohol
144
Draw butan - 1 - ol and state what type of alcohol it is
- In copy
| - Secondary alcohol
145
Draw 4 bromopentan - 2 - ol and state its molecular formula
- In copy
| - C4H9BrO
146
Draw methanol and state its molecular formula
- In copy
- HCHO / 2HCO?
- Gas at r.t
147
Draw ethanal and state its molecular formula
- In copy
- CH₃CHO
- Volatile liquid at r.t
- Low b/p --> 21C
148
Draw propanal and state its molecular formula
- In copy
| - C₂H5CHO
149
Carbonyl group is always …..
Polar
150
Draw 3 chloropropanal
- In copy
151
Draw propanone (acetone) and state its molecular formula
- In copy
- CH₃COCH₃
- Volatile liquid at r.t
- Non polar solvent
152
Draw butanone and state its molecular formula
- In copy
| - CH₃COC2H5
153
Draw pentan-2-one
- In copy
- Carbonyl
- Polar
154
Draw pentan-3-one
- In copy
- Carbonyl
- Polar
155
Draw methanoic acid (formic acid)
- In copy
| - Found in stinging ants & neetles
156
Draw ethanoic acid and state its molecular formula
- In copy
- CH₃COOH
- Weak acids --> found in vinegar
157
Draw propanoic acid and state its molecular formula
- In copy
- C₂H5COOH
- Used as a food preservative
158
Draw 4 bromobutanoic acid
- In copy
159
Draw methyl methanoate and state its molecular formula
- In copy
| - HCOOCH₃
160
Draw ethyl methanoate and state its molecular formula
- In copy
| - HCOOC₂H5
161
Draw methyl ethanoate and state its molecular formula
- In copy
| - CH₃COOCH₃
162
Name 3 esters with 4 carbons
- Ethyl ethanoate
- Methyl propanoate
- Propyl methanoate
163
Draw ethyl ethanoate and state its molecular formula
- In copy
| - CH₃COOC2H5
164
Draw methyl propanoate and state its molecular formula.
- In copy
| - C₂H5COOCH₃
165
Draw propyl methanoate and state its molecular formula
- In copy
| - HCOOC₃H7
166
What is meant by a homologous series? (L.C)
A group of compounds, all members of the group contain the same functional group and successive members differ by CH₂.
