Organic Chemistry Flashcards
(113 cards)
1
Q
What are hydrocarbons?
A
Any compound formed from only carbon and hydrogen atoms
2
Q
What is the general formula for Alkanes?
A
C(n)C(2n+2)
3
Q
What is a homologous series?
A
A group of organic compounds that react in a similar way
4
Q
What is a saturated compound?
A
A compound containing a carbon single bond, allowing each carbon to bond with the maximum number of hydrogen atoms
5
Q
What are the first four alkanes?
A
Methane, ethane, propane and butane
6
Q
What changes as the length of hydrocarbons change?
A
The properties, e.g. viscosity
7
Q
The shorter the hydrocarbon, the more…
A
… runny it is (less viscous)
… volatile it is (lower boiling points)
… more flammable it is (easier to ignite)
8
Q
What are the waste products of the combustion of hydrocarbons
A
Carbon dioxide and water vapour
9
Q
What is oxidised during combustion of hydrocarbons?
A
Both the carbon and hydrogen, as they both gain oxygen
10
Q
What is the word equation for the complete combustion of a hydrocarbon
A
Hydrocarbon + oxygen —> carbon dioxide + water + energy
11
Q
How do alkenes tend to burn in air?
A
They react with oxygen in the same way as other hydrocarbons but tend to burn in air with smoky flames because of incomplete combustion
12
Q
Why are hydrocarbons used as fuels?
A
The large amount of energy they release when they combust completely
13
Q
What type of fuel is crude oil?
A
A fossil fuel
14
Q
What is crude oil?
A
Remains of ancient biomass consisting of mainly plankton buried in mud, a mixture of a very large number of compounds
15
Q
How is crude oil formed?
A
It is formed from the remains of plants and animals (mostly plankton) that died millions of years ago.
They were buried in mud, under the high temperature and pressure, the remains turn to crude oil.
16
Q
How is crude oil extracted
A
It is drilled up from the rocks where it is found
17
Q
How are the compounds in crude oil separated?
A
By fractional distillation
18
Q
How does the fractional distillation of crude oil work?
A
- The oil is heated until it turns into a gas and enters a fractionating column
- The column has a temperature gradient (hot at the bottom, cool at the top)
- The longer hydrocarbons have higher boiling points, so condense back into liquids and drain out at the bottom of the column
- The shorter hydrocarbons have lower boiling points, condense and drain out near the top
- The crude oil is now separated into different fractions, each containing a mixture of hydrocarbons that contain a similar number carbons, therefore have similar boiling points
19
Q
How are fractions distinguished?
A
Each fraction contains molecules with a similar number of carbon atoms by fractional distillation
20
Q
Why is crude oil important in transport?
A
Oil provides the fuel for most modern transport, e.g. petrol for cars and kerosene for planes
21
Q
Why is crude oil important in the petrochemical industry?
A
They use hydrocarbons from crude oil as fuels and feedstock to make new compounds for use in e.g. polymers, solvents, lubricants and detergent
22
Q
Why can you get a large variety of products from organic compounds?
A
Carbon atoms are able bond together to form different groups called homologous series that contain similar compounds with similar properties
23
Q
What is an organic compound?
A
Compounds containing carbon atoms
24
Q
What is cracking?
A
Where longer alkane molecules produced from fractional distillation are turned into smaller, more useful ones
25
Where are short-chain hydrocarbons more useful than long chain?
They are more flammable so make good fuels and are in high demand. Also, long-chain hydrocarbons form thick gloopy liquids that aren’t very useful.
26
What type of reaction is cracking?
A thermal decomposition reaction, which is breaking down molecules by heating them (endothermic)
27
How does catalytic cracking work?
1. Heat long-chain hydrocarbons to vaporise them (turn them into gas)
2. The vapour can be passed over a hot powdered aluminium oxide catalyst
3. The long-chain molecules split apart on the surface of the specks of catalyst
This is known as catalyctic cracking
28
How does steam cracking work?
1. Vaporise the long-chain hydrocarbons
2. Mix the gaseous hydrocarbons with steam
3. Heat this up to 850 degrees, and under pressure the long chain will split into shorter chain hydrocarbons
29
What are alkenes?
Unsaturated hydrocarbons with a double bond between two of the carbon atoms in their chain
30
How can alkenes be a part of addition reactions?
The addition of atoms across means the carbon double bond can open up to make a single bond, allowing the two carbon atoms to bond with other atoms
31
How do alkenes react with hydrogen, water and the halogens?
Addition reaction
32
What are the first four alkenes?
Ethene, propene, butene and pentene
33
What is the general formula for alkenes?
C(n)H(2n)
34
What is the functional group of alkenes?
C=C
35
What is a functional group?
A group of atoms in a molecule that determines how the molecule typically reacts.
36
How do addition reactions with alkenes work?
The C=C bond will open up to leave a single bond, and a new atom is added to each carbon
37
What is the addition of hydrogen called?
Hydrogenation
## Footnote
Hydrogenation is a chemical reaction that involves the addition of hydrogen to an unsaturated compound.
38
What happens to double-bonded carbons during hydrogenation?
They open up the double bond and form a saturated alkane
## Footnote
This transformation converts alkenes into alkanes.
39
What is required for an alkene to react with hydrogen?
A catalyst
## Footnote
Catalysts lower the activation energy needed for the reaction to proceed.
40
What type of reactions do alkenes undergo with halogens?
Alkenes undergo addition reactions with halogens such as bromine, chlorine, and iodine.
## Footnote
In these reactions, the carbon-carbon double bond (C=C) is broken, and each carbon becomes bonded to a halogen atom.
41
What is formed when ethene reacts with bromine?
Dibromoethane.
## Footnote
The reaction involves two bromine atoms being added to the ethene.
42
Fill in the blank: When alkenes react with halogens, the resulting molecules are _______.
saturated.
## Footnote
Saturated molecules contain single bonds only, as opposed to the double bonds present in alkenes.
43
True or False: The reaction of alkenes with halogens produces the same product regardless of which halogen is used.
False.
## Footnote
The product varies depending on the halogen added; for example, bromine, chlorine, or iodine will yield different dibromo, dichloro, or diiodo compounds, respectively.
44
What is the general form of the reaction of ethene with bromine?
Ethene + Bromine → Dibromoethane
45
What is the effect of adding bromine water to a saturated compound like an alkane?
No reaction occurs and the solution stays bright orange
46
What happens when bromine water is added to an alkene?
The bromine adds across the double bond, making a colourless dibromo-compound
47
Which is more reactive: alkenes or alkanes?
Alkenes
48
What is observed when bromine water is decolourised?
It indicates the presence of an alkene
49
Fill in the blank: The addition of bromine to a double bond can be used to test for _______.
alkenes
50
What is the original color of bromine water before testing with alkenes?
Orange
51
What type of compound is formed when bromine reacts with an alkene?
Colourless dibromo-compound
52
What action is performed when testing for alkenes with bromine water?
Shake the bromine water with the alkene
53
How is an alcohol formed from alkenes?
Alkenes are reacted with steam, and water is added across the double bond and an alcohol is formed.
54
How can ethanol be made
Mixing ethene with steam and passing it over a catalyst
55
What is one way of making ethanol industrially?
The conversion of ethene to ethanol with steam
56
How is ethanol made using ethene and steam?
1. Steam is reacted with ethene
2. After this, the reaction mixture (gas) is passed from the reactor into a condenser where it is cooled down
3. Ethanol and water have a higher boiling point than ethene, so both condense while any unreacted ethene gas is recycled back into the reactor
4. The alcohol can then be purified from the mixture by fractional distillation, where ethanol boils first as it has a lower boiling point
57
What are polymers made up of?
Lots of the same molecule joined together in one long chain.
58
What is the process called when monomers join together to form polymers?
Polymerisation.
59
What conditions are usually needed for polymerisation?
High pressure and a catalyst.
60
What type of molecules are plastics made from?
Long-chain molecules called polymers.
61
What are the typical characteristics of the monomers that make up addition polymers?
They have a double covalent bond.
62
What happens to unsaturated monomer molecules during addition polymerisation?
They open up their double bonds and join together to form polymer chains.
63
What is an example of a monomer that can form an addition polymer?
Ethene.
64
What is the name of the polymer formed from ethene monomers?
Poly(ethene) or polythene.
65
In addition polymerisation, what is the only product formed?
The polymer.
66
How can the repeating unit in a polymer be represented?
By using 'n' to indicate there can be any number of monomers.
67
Fill in the blank: Addition polymers contain exactly the same type and number of atoms as the _______.
Monomers that formed it.
68
True or False: Addition polymers can contain different types of atoms than the monomers that formed them.
False.
69
What is the general formula of an alcohol?
CₙH₂ₙ₊₁OH
## Footnote
This formula indicates that for any alcohol with 'n' carbons, the number of hydrogens will be '2n+1' along with the hydroxyl group.
70
What functional group do all alcohols contain?
-OH
## Footnote
The -OH group is known as the hydroxyl group, which characterizes alcohols.
71
List the first four alcohols in the homologous series.
* Methanol
* Ethanol
* Propanol
* Butanol
## Footnote
Each alcohol in this series has a unique carbon chain length and corresponding formula.
72
What is the formula for Methanol?
CH₃OH
## Footnote
Methanol is the simplest alcohol, consisting of one carbon atom.
73
What is the formula for Ethanol?
C₂H₅OH
## Footnote
Ethanol is commonly known as the alcohol found in alcoholic beverages.
74
What is the formula for Propanol?
C₃H₇OH
## Footnote
Propanol can exist in two isomeric forms: 1-propanol and 2-propanol.
75
What is the formula for Butanol?
C₄H₉OH
## Footnote
Butanol has several isomers, including n-butanol and isobutanol.
76
How do you name alcohols using the basic naming system?
Replace the final '-e' with '-ol'
## Footnote
This naming convention is consistent with the naming of other organic compounds like alkanes.
77
True or False: The formula CH₃O is a correct representation of an alcohol.
False
## Footnote
CH₃O does not explicitly show the -OH functional group, which is essential for identifying alcohols.
78
Fill in the blank: The basic structure of alcohols consists of a carbon chain with a _______ functional group.
-OH
79
What are the products of the complete combustion of alcohols?
Carbon dioxide and water
80
How are alcohols reacted to form a carboxylic acid?
They are oxidised by reacting with oxygen to produce a carboxylic acid
81
Why are alcohols used as solvents in industry?
This is because they can dissolve substances that water can, but also ones that water can’t, such as hydrocarbons, oils and fats
82
What are the first four alcohols used for?
They are used as fuels, e.g. ethanol as fuel for spirit burners.
83
What are advantages of using ethanol as fuel for spirit burners?
It burns cleanly, and is not smelly
84
How is ethanol made?
Fermentation
85
Describe how fermentation works
Fermentation uses an enzyme in yeast to convert sugars into ethanol and carbon dioxide.
The ethanol produces is aqueous as the reaction occurs in a solution.
86
What are the conditions required for fermentation and why?
Fermentation happens at a temperature of around 37 degrees, in a slightly acidic solution and under anaerobic conditions
This is because the enzymes in the yeast work best in these conditions. If the temperature or pH were different, the enzyme could be denatured
87
What are the two types of polymerisation?
Addition and condensation
88
Which type of monomers does condensation polymerisation involve?
Monomers containing two different functional groups
89
What is a polyester formed from?
A diol and a dicarboxylic acid
90
What type of polymerisation occurs with polyesters?
Condensation polymerisation
91
What are by-products of condensation reactions with monomers?
They usually lose small molecules like water (that's why its called a condensation reaction)
92
What is the functional group of carboxylic acids?
-COOH
93
What is the molecular and displayed formula for methanoic acid?
HCOOH
94
What is the molecular and displayed formula for ethanoic acid?
CH3COOH
95
What is the molecular and displayed formula for propanoic acid?
C2H5COOH
96
What is the molecular and displayed formula for butanoic acid?
C3H7COOH
97
98
Describe an alcohol's reaction with sodium
Fizzing as hydrogen is produced
Sodium alkoxide and hydrogen products
99
Describe an alcohol's reaction with water
First three dissolve in water to form a neutral solution (fourth partially dissolves)
100
Describe an alcohol's reaction with an oxidising agent
Colour change is observed, fizzing
A carboxylic acid and water is produced
101
Describe an alcohol's combustion in air
Alcohol burns with a clean blue flame, produces carbon dioxide and water
102
Describe what happens when any of the first four carboxylic acids react with carbonates
Fizzing is observed as carbon dioxide gas is produced. Products are salt, water and carbon dioxide
103
Describe what happens when any of the first four carboxylic acids dissolve in water
They dissolve well in water to form weakly acidic solutions, only partially ionise in water. Form a clear solution with no obvious visual change.
104
Describe what happens when any of the first four carboxylic acids react with alcohols
Forms an ester and water in a condensation reaction requiring a strong acid catalyst and heat. Often a sweet smell found due to ester formation
105
Why are carboxylic acids weak?
Only partially ionises in water, leading to a lower concentration of H+ ions and therefore a higher pH than strong acids.
106
What is the only ester you must know?
Ethyl ethanoate
107
How many different functional groups do amino acids have in a molecule?
2
108
What do amino acids react by condensation polymerisation to produce?
They produce polypeptides
109
How are proteins made?
Different amino acids are combined in the same chain
110
What is DNA and what does it do?
A large molecule essential for life. It encodes genetic instructions for the development and functioning of living organisms and viruses
111
What are most DNA molecules made from?
It is two polymer chains made from four different monomers called nucleotides, in the form of a double helix.
112
What are some naturally occurring polymers that are important for life?
Proteins, starch, cellulose and DNA
113
Which type of monomer are starch and cellulose made from?
Glucose monomers
