Unit 2.4 - Organic Compounds Flashcards
1
Q
What IS organic chemistry?
A
The chemistry of carbon compounds
2
Q
What’s another word for organic chemistry?
A
Carbon chemistry
3
Q
How many carbon compounds are there?
A
Millions, with the number increasing daily
4
Q
What do carbon compounds contain in general?
A
Hydrogen
5
Q
Name 2 compounds that do contain carbon but aren’t considered carbon compounds
A
CO2 and carbonates
6
Q
Why are CO2 and carbonates not considered to be carbon compounds?
A
They don’t contain hydrogen
7
Q
What are some elements often found in carbon compounds?
A
Nitrogen
Oxygen
Halogens
Sulphur
Phosphorus
8
Q
Why does carbon form so many compounds?
A
- Carbon is in group IV in the periodic table and has 4 electrons in its outer shell
When forming compounds, they’re covalent compounds
Carbon forms 4 covalent bonds in its compounds to achieve a stable electronic structure - Carbon forms strong covalent bonds with itself and hydrogen atoms - stable and resistant to oxidation and hydrolysis
Extremely high activation energy needs to be overcome
9
Q
What are the C-C bonds that carbon forms found in?
A
Chain and ring systems
10
Q
Describe organic reactions and explain why they’re like this
A
Generally slow
Poor yields
Extremely high activation energy needs to be overcome
11
Q
Why are organic reactions slow and have poor yields?
A
Strong C-C bonds
12
Q
What are the 4 different types of formulae we can use to represent organic compounds?
A
Molecular, graphic shortened and skeletal structural formulae
13
Q
What does a molecule formula show?
A
The actual amount of atoms of each element in a molecule
14
Q
Describe how molecular formulae are set out
A
Symbol for the element with subscripts to show how many of each atom in the molecule
15
Q
In which order do we write the elements in a molecular formula?
A
C, H, O
then alphabetical
16
Q
What do molecular formulae NOT show us?
A
HOW atoms are bonded
17
Q
What is a graphic structural formula?
A
Displayed structural formula
18
Q
What does a graphic structural formula show?
A
How elements are bonded and the types of bonds
19
Q
What does a single line represent in graphic structural formulae?
A
A single covalent bond
20
Q
What does a double line represent in graphic structural formulae?
A
Double covalent bond
21
Q
How many bonds must carbon form? Describe these
A
4
Can be single, double or triple
With itself or other elements
22
Q
What’s another type of bond that carbon forms and in what type of compounds are these formed?
A
Delocalised bonds
Aromantic
23
Q
What type of bonds do aromantic compounds have?
A
Delocalised bonds
24
Q
What type of compounds contain delocalised bonds?
A
Aromantic
25
What do shortened structural formulae show?
The graphic structural formula as a shortened structural formula
(Slightly different to molecular formulae)
26
What are skeletal structural formulae?
Shorthand representation of a compound’s molecular structure
27
Why are skeletal structural formulae useful?
Show complicated structures clearly
Quick and simple to draw
28
What’s implicit on a skeletal structural formula?
The location of the carbon atoms with hydrogens bonded
29
Where are carbon atoms implied to exist on skeletal structural formulae?
At each vertex (the second the pen touches the paper is one)
30
How do we figure out the number of hydrogen atoms from a skeletal structural formula? Why?
4 - (number of bonds drawn to that carbon)
Carbon has 4 covalent bonds
31
How do we represent hydrogen atoms bonded to non-carbon atoms in a skeletal structural formula? Give an example
Draw them explicitly
H bonded to O, for example
32
How do we signify all atoms that aren’t carbon or hydrogen on a skeletal structural formula?
With chemical symbols
33
Homologous series
Groups of related compounds
34
What’s the purpose of homologous series?
To make the study of the millions of carbon compounds easier
35
Draw the skeletal structural formula of propan-1-ol
(See notes)
36
Draw the skeletal structural formula of ethene
(See notes)
37
What’s ethene used for?
Used to make polymers
38
What’s ethanoic acid found in?
Vinegar
39
What type of acid is in vinegar?
Ethanoic
40
Name a compound used to make polymers
Ethene
41
Draw the skeletal structural formula of propene
(See notes)
42
Draw the skeletal structural formula of ethanoic acid
(See notes)
43
In which case does a tip of a skeletal structural formula not count as a carbon atom?
If it has a completely different element like OH attached to it
44
What do you call the members of the family in a homologous series?
Homologues
45
Homologues
All in the same homologous series
46
What do members of the same homologous series all have?
The same functional group
The same general formula
Similar chemical properties
Gradually changing physical properties
47
Functional group
An element or group of elements responsible for the chemical properties/behaviour of the compound in a homologous series
Provides a reactive site
48
What provides a reactive site in a homogenous series?
Functional group
49
What’s organic chemistry largely the chemistry of?
Homologous series rather than individual compounds
50
Alkane…
Functional group
Systematic name
Example
(N/A)
-ane
Ethane
51
Alkene…
Functional group
Systematic name
Example
C=C
-ene
Ethene
52
Halogenoalkane…
Functional group
Systematic name
Example
-Fl, -Cl, -Br, -I
Fluoro, chloro, bromo, iodo
Chloroethane
53
Primary alcohol…
Functional group
Systematic name
Example
-CH2OH
-1-ol
Propan-1-ol
54
Secondary alcohol…
Functional group
Systematic name
Example
CH(OH)
-2-ol
Propan-2-ol
55
Carboxylic acid…
Functional group
Systematic name
Example
-COOH
-oic acid
Ethanoic acid
56
Aldehyde…
Functional group
Systematic name
Example
CHO
-al
Propanal
57
Ketone…
Functional group
Systematic name
Example
-co-
-one
Propanone
58
Ester…
Functional group
Systematic name
Example
-COO-
-oate
Ethyl propanote
59
Do you count the C in COOH in carboxylic acids?
Yes
60
How many double bonds between carbon atoms to alkenes have?
At least 1
61
General formula of alkanes
CnH2n+2
62
General formula of alkenes
CnH2n
63
Which homologous series is ethane a part of?
Alkanes
64
Which homologous series is ethene a part of?
Alkenes
65
Which homologous series is Chloroethane a part of?
Halogenoalkanes
66
Which homologous series is propan-1-ol a part of?
Primary alcohol
67
Which homologous series is ethanol a part of?
Primary alcohols
68
Which compounds are part of the primary alcohol homologous series but don’t have the usual systematic name?
Methanol and ethanol
69
Which homologous series is propan-2-ol a part of?
Secondary alcohols
70
Which homologous series is ethanoic acid a part of?
Carboxylic acids
71
Which homologous series is propanal a part of?
Aldehydes
72
Which homologous series is propanone a part of?
Ketones
73
Which homologous series is ethyl propanoate a part of?
Esters
74
Describe the activity of alkanes
Largely inactive
75
Name 2 reactions in which alkanes actually do undergo?
Combustion
Cracking
76
Do alkanes have any double bonds? What does this mean for them?
No
They’re saturated
77
Give an example of a ketone
Acetone (nail varnish remover)
78
Name for carbon chain compounds
Aliphatic compounds
79
Aliphatic compounds
Carbon chain compounds
80
What are carbon chain compounds named after?
The parent alkane
81
What are the steps to naming an organic compound?
1. Largest carbon chain is found - work out the parent alkane
2. The functional group is found (going to be from the table)
3. Any side groups (radicals) are found
4. Assign a number to each carbon atom in the longest chain to find the position of the functional groups or side groups. Always use the lowest numbers possible.
82
What do we always use as the number for the positioning of the side groups in an organic compound?
The smallest number from the end
83
Parent alkane if the longest carbon chain is 1 carbon atom long
Methane
84
Parent alkane if the longest carbon chain is 2 carbon atoms long
Ethane
85
Parent alkane if the longest carbon chain is 3 carbon atoms long
Propane
86
Parent alkane if the longest carbon chain is 4 carbon atoms long
Butane
87
Parent alkane if the longest carbon chain is 5 carbon atoms long
Pentane
88
Parent alkane if the longest carbon chain is 6 carbon atoms long
Hexane
89
Name given to the side groups of organic compounds
Branching
90
What is the root name and radical of the side group of formula CH3?
Methane
Methyl
91
What is the root name and radical of the side group of formula CH3CH2?
Ethane
Ethyl
92
What is the root name and radical of the side group of formula CH3CH2CH2?
Propane
Propyl
93
Formula of radical methyl
CH3
94
Formula of radical ethyl
CH3CH2
95
Formula of radical propyl
CH3CH2CH2
96
Draw the skeletal structural diagram for 2-methylpropane
(See notes) - in the naming section
97
Draw the skeletal structural formula of 2-bromobutane
(See notes) - in naming section
98
Draw the skeletal structural formula of 2methylpropan-1ol
(See notes) - in naming section
99
Where do we place the number in the name of a compound when specifying the position of a double bond?
Between the word
100
When do we place the number between the word in an organic compounds name?
When specifying the position of a double bond
101
Do we count the carbon atoms in side groups?
No
102
When don’t we count the carbon atoms of a compound?
If it’s part of a side group
103
Draw the side group of a compound in skeletal structural formula, for example for 2-methylpropane
(See notes) - in naming section
104
Draw the graphic structural formula of trichloroethene
(See notes)
105
Um jw en Owen 96 gw en
F
106
What do molecular formulae of an organic compound not give information about in terms of atoms in a molecule?
Their arrangement
107
Isomers
Molecules with the same formula with different structures
108
Structural isomers
Have the same molecular formula but different structural formulae
109
What can structural isomers be found in?
Substances with the same functional group
Substances with different functional groups
110
Show the isomers of butane - what’s significant about them?
(See notes)
Both have the same functional group
111
Name substances that have isomers yet have different functional groups
Carboxylic acids and esters
112
What’s similar and what’s different between carboxylic acids and esters? Give an example
Same molecular formulae
Very different elements e.g -
Ethanoic acid - sour, bitter smell
Methyl methanoate (ester) - sweet smell
113
What do E-Z isomers appear in?
Alkenes
114
What type of bonds are significant in alkenes?
C=C bond
115
What are alkenes due to the C=C bond that they possess?
Unsaturated
116
What can single bonds do in a saturated molecule and what does this mean for them?
No double bonds - can freely rotate
Atoms in the bond are interchangeable
117
What cannot occur in unsaturated molecules with double bonds and why?
There is no free rotation due to the double C=C bond
The pi bond in an alkene prevents the rotation - we can’t interchange the atoms
118
What prevents the rotation of atoms in alkenes?
The pi bond prevents the rotation
119
Are alkenes saturated or unsaturated and why?
Unsaturated due to the presence of the double C=C bond
120
What type of isomers occur in alkenes?
E-Z isomers
121
E-Z molecules
Same old ulnar and structural formula,but different spatial arrangement of atoms
122
What’s an E molecule?
Both prioritised atoms on the different side of the double bond
123
What’s a Z-molecule?
Both prioritised atoms on the same side of the double bond
124
How do we remember that the prioritise atoms on a Z-molecule are on the same side?
“Zame zide”
125
What do we prioritise atoms in terms of when describing E-Z isomers?
Atomic mass
126
How did E-Z molecules get their name?
From the German…
E - entagen (opposite)
Z - zusammen (together)
127
What must each carbon atom on the double bond have in order to form E-Z isomers?
2 different groups or atoms
(e.g - Br and H)
128
What would imply that two isomers are NOT E-Z isomers?
2 atoms that are the same on the same side of the double bond
129
What are the 2 types of bond in the double bond in ethene?
Covalent bond
Pi bond
130
How does the covalent bond in ethene form?
By direct overlap of two orbitals
131
How does the pi bond in ethene form?
By the sideways overlap of two px orbitals
132
What do both the covalent bond and the pi bond result in?
A bond which can be imagined to be a charge cloud above and below the plane of the molecule
133
Draw a diagram to represent the nature of the pi bond in ethene
(See notes)
134
Draw the skeletal structural formula of 2-methylpropan
(See notes) - in naming section
135
Draw 2-2-dimethylbutane
(see notes)
136
What are the 3 types of reagents in organic chemistry?
Radicals
Nucleophiles
Electrophiles
137
When do radicals form?
When a covalent bond breaks
138
What is a radical reagent?
When a covalent bonds breaks, each atom/species retains one electron from the bond
The species which form are free radicals
139
Properties of radicals
Have an unpaired electron
Are very reactive, and react with other free radicals or atoms
Reactions involving free radicals are extremely rapid
140
Name 3 typical reactions that involve free radicals
Photochlorination of methane
Alkene polymerisation
Cracking and ozone depletion
141
Give 3 typical free radicals
Cl•
Cl3•
CH3CH2•
142
What is the symbol for a free radical?
•
(At the top)
143
What do you get when you crack a large alkane?
Free radicals
144
Hat can break up chlorine molecules into free radicals?
Ultraviolet light
145
What do some reagents that react with organic compounds seek out?
Centres of charge
146
Why do organic molecules often contain centres of charge?
Due to the presence of polar covalent bonds or pi bonds
147
Nucleophiles
Ions or molecules which can donate a lone pair of electrons, forming a covalent bond
148
What are Nucleophiles attracted to?
Positive changes or positive centres of charge
149
Give an example of a positive centre of charge
Nucleus
150
What’s polar in a Halogenoalkane and what happens to it therefore?
The carbon-halogen bond is poalr
The Nucleophiles will attack the positive carbon centre
151
Give some examples of typical Nucleophiles
OH-
Br-
CN-
H2O
NH3
152
Which part of a Nucleophiles attracts other molecules?
The lone pairs of electrons
153
How are Nucleophiles charged?
Either negatively or neutrally charged
154
Elctrophiles
Ions or molecules which can accept a lone pair of electrons, forming a covalent bond
155
What are electrophiles attracted to?
Negative charges or negative centres of charge
156
What is the centre of negative charge in an alkene?
The pi bond
157
What is the pi bond to an alkene?
A centre of negative charge
158
What will an electrophile attack in an alkene?
The centre of negative charge, which is the pi bond
159
Which homologous series gave centres of negative charge that electrophiles attack and what is this centre?
Alkenes
Pi bond
160
Give some examples of typical electrophiles
H+
NO2+
Cl+
161
How are electrophiles charged?
Positively
162
What are the 5 types of reaction?
Addition
Substitution
Elimination
Oxidation/reduction (redox)
Hydrolysis
163
What happens during an addition reaction?
2 molecules are brought together to produce 1 molecule
164
Give an equation to represent addition reactions
A + B —> C
165
What usually has to be available for an addition reaction to occur?
A double bond
166
What type of reaction usually requires a double bond in order to occur?
Addition reaction
167
What do alkenes always undergo? (Type of reaction)
Why?
Electrophilic addition
The C=C double bond is attacked
168
Substitution reaction
An atom or group of atoms replace another atom or group of atoms in a molecule
169
What normally has to be true after a substitution reaction?
The nature of the group which is introduces must be similar to that of the group which is replaced
170
Give an equation to represent a substitution reaction
AB + C —> AC + B
171
Give an example of a Nucleophiles substitution reaction
A hydroxide ion acting as a Nucleophile when it attacks the polar C-Br bond
172
Which reaction is an example of free radical substitution?
The photochlorination of methane
173
Why is the photochlorination of methane an example of free radical substitution?
Methane reacts with chlorine radicals
174
Elimination reaction
A simple molecule such as water is eliminated from the molecule
175
What often forms as a result of an elimination reaction?
A double bond
176
In which type of reaction is a double bond usually formed?
Elimination
177
What is an elimination reaction also known as if water is eliminated?
A dehydration reaction
178
Dehydration reaction
Type of elimination reaction where water is eliminated
179
Give an equation to represent an elimination reaction - what’s significant about this?
AB —> A + B
Opposite of addition reaction
180
What are the 2 things that usually form during an elimination reaction?
Organic molecule with double bond
Small molecule
181
Typical redox reaction example
Combustion
182
What does a redox reaction consist of?
Both oxidation and reduction - we can’t have one without the other
183
What rule can also be followed for determining which elements have been oxidised or reduced in a redox reaction as opposed to using OILRIG?
Oxidation
Gain of oxygen
Loss of hydrogen
Reduction
Loss of oxygen
Gain of hydrogen
184
What is oxidation in terms of oxygen and hydrogen?
Gain of oxygen
Loss of hydrogen
185
What is reduction in terms of oxygen and hydrogen?
Loss of oxygen
Gain of hydrogen
186
What occurs to primary alcohols in redox reactions?
Total oxidation
187
What happens to oxidising agents?
They’re reduced
188
Hydrolysis
Chemical reaction between the organic compound and water
189
Describe a hydrolysis reaction
Very slow and so usually require a catalyst
190
Common catalysts used in hydrolysis reactions
Sodium hydroxide
Hydrochloric acid
191
What type of hydrolysis reaction is one catalysed by sodium hydroxide?
Base catalysed
192
What type of hydrolysis reaction is one catalysed by hydrochloric acid?
Acid catalysed
193
What do empirical and molecular formulae show?
The ratio of atoms in the molecule
Actual number of atom in a molecule
194
What are the steps to writing an empirical formula?
Write symbols
Write masses/percentages from question
Divide each mass/percentage by the mass number of that element (Ar)
Divide each answer by the smallest number to find the ratio
(Do NOT round up/down ratios at the end - multiply everything up into whole numbers if they’re in decimals)
195
What do we NOT do at the end when working out empirical formulae and what do we do instead?
Round up/down
Multiply everything up into whole numbers
196
What are the steps to working out a molecular formula from an empirical formula?
Relative molecular mass (in question)
—————————————————. = a multiple
Mr of empirical formula
Multiply every atom of the empirical formula by this
197
What do we need to be given in the question in order to calculate the molecular formula from an empirical formula?
The relative molecular mass
198
How do we order the side groups in the name of a compound if there’s more than one of them?
Put them in alphabetical order
199
How are the particles held together in a solid?
Rigidly
200
How can the particles of a solid vibrate?
They’re rigid - can only vibrate around a fixed position
201
What must happen for a solid to melt?
Forces that hold it rigidly must be overcome
202
How are the particles in a liquid difference to those in a solid?
Less order, held together less rigidly and particles are further apart
203
What’s important about the particles of a liquid, even though there’s less order and they’re further apart than in a solid?
There;s still significant attractive forces to overcome when changing into a gas
204
What is needed to overcome the forces between particles in a solid or liquid when it melts or boiled?
Forces
205
How are the forces in a solid or liquid usually overcome to cause a substance to melt or boil?
Using energy, that’s usually heat/latent heat
206
How can we product which substance has the higher melting or boiling point?
Look at the strength of the forces between particles
207
What type of molecules are hydrocarbons?
Simple covalent molecules
208
What are the only things that hydrocarbons consist of?
Hydrogen and carbon atoms
209
Are hydrocarbons polar or non-polar? Why?
Non-polar
Electronegativities of carbon and hydrogen are similar
210
What’s the only type of force present in hydrocarbons and why?
Temporary dipole-temporary dipole (Van der Waal forces)
Hydrocarbons are non-polar
211
What’s significant about the Van der Waal forces in a hydrocarbon?
Weak intermolecular forces that require little energy to overcome
212
Where do Van der Waal forces act on hydrocarbons?
Between the surfaces of the molecules
213
When will the Van der Waal forces of molecules act more?
The more surface that’s in contact, the more the forces will act
214
What does more hydrocarbon surface in contact mean for their boiling point?
More surface in contact = more the forces will act
=more energy needed to overcome the forces
=higher melting and boiling points
215
What is the relationship between the amount of surface in contact between molecules and their boiling points?
More surface in contact = higher melting and boiling points
(Forces act more = more energy required to overcome the forces)
216
What’s the relationship between the amount of carbon atoms a hydrocarbon has and it’s boiling point? Why?
More carbon atoms = increased boiling point
(Van der Waal attractions increases)
217
What’s the relationship between the relate molecular mass of a hydrocarbon and its boiling point? Why?
Higher relative molecular mass = higher boiling point
(More carbon atoms = Van der Waal attractions increase)
218
What else can have an impact on the boiling temperature of a hydrocarbon apart from the chain length?
Branching
219
What effect do different structural isomers have on hydrocarbons?
Give them different boiling points
220
Why do different structural isomers of hydrocarbons give them different boiling points?
Difference surface areas are in contact for different isomers
221
What do more branches do to the shape of a molecule?
More branches = more spherical molecule
222
What happens to the amount of surface area for contact in molecules if spheres are packed together?
The surface area available for surface area contact is very small
223
What’s good about sausage shaped molecules?
Much more surface area available for surface area contact compared to spherical molecules
224
What effect does the branching of an isomer have on an isomer and why?
More branches = more like a sphere = surface area available for surface area contact is very small = weaker Van der Waal forces = lower boiling temperature
225
What type of hydrocarbons are often used in the oil industry and why?
Branched
More spherical = less surface area available for surface area contact = lower boiling temperature
226
Which group do alcohols contain?
OH group
227
What does the OH group in alcohols cause and what does this lead to?
Hydrogen bonds
Increased boiling point
228
Why does having an OH group in an alcohol lead to an increase in their boiling points?
Hydrogen bonds are formed, which are stronger than Van der Waal forces
229
What does having hydrogen bonds in a hydrocarbon lead to?
Increased boiling point
More soluble in water
230
Parent Alkane if the longest carbon chain has 7 atoms
Heptane
231
What’s the difference in naming the AMOUNT vs the POSITIONING of side groups on hydrocarbons?
di, tri… = the amount of side groups
2,3… (numbers) = the positioning of side groups
232
How would we show that the %’s of elements in an alkane are consistent with its formula?
Mr of formula
Ar (from formula) of each element divided by Mr - the %’s should match up
233
Which phrase should you always add at the end after describing which compounds have the lowest boiling point?
“so less energy is needed to separate the molecules”1
234
Free radial definition
A species with an unpaired electron
235
Why do chlorine radicals for but fluorine radicals don’t?
C-F bond is stronger than C-Cl bond
236
What must be true for E-Z isomerism to occur?
*Both* carbon atoms on the double bond must have 2 *different* groups or atoms
237
What do we need to show when drawing nucleophies?
Lone pairs of electrons
