topic 7 - organic chemistry Flashcards
(138 cards)
1
Q
What is crude oil?
A
Crude oil is a finite resource found in rocks consisting mainly of the remains of ancient biomass primarily plankton that was buried in mud. It is a mixture of a very large number of compounds.
2
Q
What defines a mixture?
A
A mixture is composed of 2 or more elements that are not chemically combined. The chemical properties of each substance in the mixture remain unchanged.
3
Q
How can substances in a mixture be separated?
A
Substances in a mixture can be separated by physical methods such as distillation.
4
Q
What are hydrocarbons?
A
Hydrocarbons are compounds made up of hydrogen and carbon only. They are often found in crude oil and can be saturated or unsaturated.
5
Q
What is the general formula for hydrocarbons?
A
The general formula for hydrocarbons is C n H 2n+2.
6
Q
What are alkanes?
A
Alkanes are saturated hydrocarbons that have single bonds between carbon atoms. They are characterized by the general formula C n H 2n+2.
7
Q
List the first four alkanes and their corresponding formulae.
A
The first four alkanes are: 1. Methane (CH4) 2. Ethane (C2H6) 3. Propane (C3H8) 4. Butane (C4H10) - Mnemonic: MEPB (Monkeys Eat Peanut Butter).
8
Q
What is fractional distillation?
A
Fractional distillation is a physical separation method used to separate mixtures based on differences in boiling points of the components.
9
Q
What is the significance of fractional distillation in relation to crude oil?
A
Fractional distillation is used to separate the different fractions of crude oil allowing the extraction of various hydrocarbons for fuels and feedstock.
10
Q
What is the composition of most compounds found in crude oil?
A
Most compounds found in crude oil are hydrocarbons which consist solely of hydrogen and carbon atoms.
11
Q
What are the properties of the compounds in crude oil?
A
The chemical properties of each compound in crude oil remain unchanged as they are part of a mixture.
12
Q
What are the characteristics of saturated hydrocarbons?
A
Saturated hydrocarbons like alkanes have only single bonds between carbon atoms and the maximum number of hydrogen atoms attached.
13
Q
What is the formula for the first alkane methane?
A
The formula for methane the first alkane is CH4.
14
Q
How are hydrocarbons important in chemistry?
A
Hydrocarbons are fundamental in organic chemistry and serve as fuels and raw materials for chemical synthesis.
15
Q
Explain the process of how crude oil is formed.
A
Crude oil is formed from the remains of ancient marine organisms primarily plankton that were buried under layers of mud and subjected to heat and pressure over millions of years.
16
Q
What is the process of separating hydrocarbons in crude oil called?
A
The process is called fractional distillation which occurs in a fractionating column where heated crude oil is separated into different fractions based on boiling points.
17
Q
How does the fractionating column operate continuously?
A
Heated crude oil is piped in at the bottom of the fractionating column. Vaporized oil rises up the column and different fractions condense at various levels corresponding to their boiling points.
18
Q
What are fractions in terms of crude oil?
A
Fractions are groups of hydrocarbons in crude oil that have similar numbers of carbon atoms and are separated during the refining process.
19
Q
What types of fuels can be produced from crude oil?
A
Common fuels produced from crude oil include petrol (gasoline) diesel oil kerosene heavy fuel oil and liquefied petroleum gases.
20
Q
What are some products of the petrochemical industry?
A
The petrochemical industry produces a variety of materials including solvents lubricants polymers and detergents.
21
Q
What is the significance of petrochemicals in modern life?
A
Petrochemicals are crucial as they provide essential fuels and raw materials for numerous products that support modern lifestyles such as energy sources and everyday materials.
22
Q
What role do boiling points play in the fractionating column process?
A
Boiling points determine the temperature at which different hydrocarbons condense; lighter fractions with lower boiling points rise higher in the column while heavier fractions condense lower down.
23
Q
Why is fractional distillation essential in the petrochemical industry?
A
Fractional distillation is essential because it allows for the separation of different hydrocarbons in crude oil enabling the production of specific fuels and raw materials required for various industrial applications.
24
Q
What kind of hydrocarbons are found in crude oil?
A
Crude oil contains a complex mixture of hydrocarbons including alkanes cycloalkanes aromatics and various other organic compounds.
25
In what form are crude oil fractions collected during the distillation process?
Fractions are collected in liquid form as they condense at specific temperatures in the fractionating column.
26
What happens to the hydrocarbons during the heating in the fractionating column?
The hydrocarbons are heated until they evaporate and then rise through the column where they cool and condense at different levels based on their corresponding boiling points.
27
What is the general structure of hydrocarbons?
Hydrocarbons are organic compounds composed exclusively of hydrogen and carbon atoms which can form chains or rings.
28
How does the temperature affect the separation of hydrocarbons in the fractionating column?
Temperature directly affects the boiling points of hydrocarbons; each fraction condenses at its specific boiling point allowing for effective separation based on rising vapor temperatures.
29
Can you give an example of a synthetic polymer derived from petrochemicals?
An example of a synthetic polymer derived from petrochemicals is polyethylene which is widely used in plastic products.
30
What are solvents and why are they important in the petrochemical industry?
Solvents are substances that dissolve other materials without changing their chemical composition; they are important for processes like extraction purification and formulation of products in the petrochemical industry.
31
What differentiates natural and synthetic petrochemicals?
Natural petrochemicals are derived directly from fossil fuels or biological sources while synthetic petrochemicals are chemically manufactured from raw materials processed in the petrochemical industry.
32
Can you explain how detergents are related to petrochemicals?
Detergents are surfactants that lower the surface tension of liquids and many detergents are produced from petrochemical feedstocks using processes that modify the hydrocarbon chains.
33
What are the properties of hydrocarbons that depend on the size of their molecules?
1. Viscosity: Shorter hydrocarbon molecules are less viscous and more runny while longer molecules are more viscous.
34
2. Boiling Point: Shorter molecules have lower boiling points and lower temperatures at which they vaporize or condense.
35
3. Flammability: Shorter molecules are generally more flammable than longer ones.
36
What is the significance of hydrocarbons in fuel usage?
Hydrocarbons are burned to produce energy releasing carbon dioxide and water as products. The hydrogen and carbon atoms in hydrocarbons are oxidized during this reaction resulting in energy that can be harnessed as fuel.
37
What do hydrocarbons produce when burned?
When hydrocarbons are burned they produce carbon dioxide (CO2) and water (H2O). This combustion reaction involves the oxidation of hydrogen and carbon.
38
What are the two methods of cracking hydrocarbons mentioned in the document?
The two methods of cracking hydrocarbons are:
39
1. Catalytic Cracking: Involves passing hydrocarbons over a hot catalyst to vaporize them.
40
2. Steam Cracking: Involves mixing hydrocarbons with steam and heating it to a very high temperature.
41
What is the purpose of cracking hydrocarbons?
The purpose of cracking hydrocarbons is to produce smaller more useful molecules from larger hydrocarbon molecules.
42
How does the size of hydrocarbon molecules affect their use as fuels?
The size of hydrocarbon molecules affects several key properties:
43
1. Smaller molecules are more suitable for use in fuels due to lower viscosity lower boiling points and higher flammability making them easier to ignite and use as energy sources.
44
2. Longer molecules tend to be more viscous and have higher boiling points which can make them less efficient as fuels.
45
Explain the process of catalytic cracking.
Catalytic cracking involves heating hydrocarbons and passing them over a catalyst to facilitate the breakdown of larger hydrocarbon molecules into smaller more useful ones. The catalyst lowers the energy required for the reaction making it more efficient.
46
Explain steam cracking and its importance in hydrocarbon processing.
Steam cracking is a thermal process where hydrocarbons are mixed with steam and heated to high temperatures resulting in the breakdown of larger hydrocarbons into smaller molecules. This method is crucial for producing valuable smaller hydrocarbons such as ethylene and propylene which are used in the production of plastics and other chemicals.
47
What are the environmental implications of burning hydrocarbons?
Burning hydrocarbons produces carbon dioxide a greenhouse gas that contributes to climate change. Moreover the combustion process can also lead to the release of pollutants including carbon monoxide and nitrogen oxides which can have negative effects on air quality and human health.
48
What temperature is required for thermal decomposition reactions such as steam cracking?
Thermal decomposition reactions including steam cracking of hydrocarbons typically require high temperatures often around 700°C to 900°C to facilitate the breaking of chemical bonds.
49
What are the products of the cracking process?
The products of cracking include alkanes and unsaturated hydrocarbons known as alkenes.
50
What is the general formula for alkenes?
The general formula for alkenes is C_nH_(2n) where n is the number of carbon atoms in the molecule.
51
What are the first two alkenes in the alkene series?
The first two alkenes are ethene (C2H4) and propene (C3H6).
52
How can unsaturated hydrocarbons like alkenes be represented?
Unsaturated hydrocarbons like alkenes can be represented with structural formulas showing their double bonds or as molecular formulas (e.g. ethene: C2H4 propene: C3H6).
53
How do alkenes react with bromine water?
Alkenes react with bromine water causing the solution to change from orange to colourless due to the addition of bromine across the double bond demonstrating their reactivity.
54
Why do alkenes react with bromine water while alkanes do not?
Alkenes contain a double bond which makes them more reactive than alkanes; alkanes only have single bonds which do not react with bromine water.
55
What are some uses of alkenes?
Alkenes are used for producing other chemicals including polymers which are important in various industrial applications.
56
Why are some products made from cracking preferred as fuels?
Some products made from cracking are preferred as fuels because they have shorter hydrocarbon chains than the original alkanes making them more flammable and effective as fuels.
57
What is a key requirement when writing chemical equations for cracking?
When writing chemical equations for cracking it is crucial to ensure that there are the same number of carbon and hydrogen atoms on both sides of the equation.
58
Explain the term 'thermal decomposition'.
Thermal decomposition is a chemical process where a compound is broken down into simpler substances by the action of heat.
59
What is steam cracking?
Steam cracking is a specific type of thermal decomposition that uses steam and high temperatures to break down larger hydrocarbons into smaller alkenes and alkanes.
60
How does the flammability of smaller hydrocarbons compare to larger ones?
Smaller hydrocarbons tend to be more flammable than larger hydrocarbons which makes them more advantageous as fuels.
61
Define the term 'saturated hydrocarbon'.
A saturated hydrocarbon is a hydrocarbon that contains only single bonds between carbon atoms and is fully saturated with hydrogen atoms.
62
What is the relationship between the number of carbon atoms and the number of hydrogen atoms in alkenes?
In alkenes the number of hydrogen atoms is always double the number of carbon atoms plus an additional two (C_nH_(2n) structure).
63
What distinguishing feature do alkenes have that makes them different from alkanes?
Alkenes have at least one double carbon-carbon bond which distinguishes them from alkanes which only have single bonds.
64
What is the general formula for alkenes?
The general formula for alkenes is C_nH_(2n) where 'n' is the number of carbon atoms.
65
What defines an alkene?
Alkenes are defined as hydrocarbons that have at least one carbon-carbon double bond making them unsaturated compounds.
66
Why are alkenes considered unsaturated?
Alkenes are considered unsaturated because they contain two fewer hydrogen atoms than the corresponding alkane with the same number of carbon atoms.
67
List the first four alkenes in order.
The first four alkenes are ethene (C2H4) propene (C3H6) butene (C4H8) and pentene (C5H10).
68
What is the significance of functional groups in organic chemistry?
Functional groups are significant in organic chemistry as they are the portions of molecules responsible for the characteristic chemical reactions of those molecules.
69
What is the chemical reaction of alkenes with oxygen called?
The chemical reaction of alkenes with oxygen is called a combustion reaction.
70
If you combine C6H14 with C2H4 how do you calculate the remaining carbon and hydrogen atoms?
To calculate the remaining carbon and hydrogen atoms after the reaction subtract the number of carbon and hydrogen atoms in the added molecule (C2H4) from the total carbon and hydrogen in the first molecule (C6H14). This gives: C: 6 - 2 = 4 and H: 14 - 4 = 10 resulting in the remaining molecule C4H10.
71
What is the structure of alkenes?
Alkenes can be represented in various structural forms including linear branched and cyclic structures but they will always include at least one double bond between carbon atoms.
72
What type of reactions do alkenes typically undergo?
Alkenes typically undergo addition reactions due to the presence of the carbon-carbon double bond allowing other atoms or groups to add across the double bond.
73
What are unsaturated hydrocarbons?
Unsaturated hydrocarbons are hydrocarbons that contain one or more double or triple bonds reducing the maximum number of hydrogen atoms that can be attached to the carbon chain.
74
What is the general behavior of alkenes when burned in air?
Alkenes tend to burn in air with smoky flames due to incomplete combustion resulting in the formation of carbon or carbon monoxide (CO).
75
What type of reactions do alkenes undergo with hydrogen water and halogens?
Alkenes react with hydrogen water and halogens via addition reactions where atoms are added across the carbon-carbon double bond converting the double bond into a single carbon-carbon bond.
76
What is the reaction of ethene (C2H4) when it reacts with bromine (Br2)?
When ethene (C2H4) reacts with bromine (Br2) the double bond is broken and bromine atoms are added across the former double bond.
77
What is the reaction of propene (C3H6) when it reacts with water?
When propene (C3H6) reacts with water the double bond is broken and water is added typically forming propanol.
78
Explain the addition of hydrogen (H2) to butene (C4H8).
In the reaction of butene (C4H8) with hydrogen (H2) the double bond is broken to form a single bond and the hydrogen atoms are added across the double bond.
79
How does the addition of hydrogen (H2) occur in the reaction with alkenes?
In the addition of hydrogen (H2) to alkenes H2 splits into two hydrogen atoms which are added to the two different carbons in the broken carbon-carbon double bond.
80
What is the splitting result of water (H2O) and its reaction with alkenes during addition reactions?
Water (H2O) splits into one hydrogen atom (H) and one hydroxyl group (OH) which are added to the respective carbons of the broken double bond.
81
What is the splitting result of bromine (Br2) in reactions with alkenes?
Bromine (Br2) splits into two bromine atoms which are then added to the two different carbons in the broken carbon-carbon double bond of alkenes.
82
Define alcohols in terms of their functional group.
Alcohols are organic compounds that contain the functional group hydroxyl (OH).
83
List the first four members of the alcohol series.
The first four members of the alcohol series are methanol (C1H3OH) ethanol (C2H5OH) propanol (C3H7OH) and butanol (C4H9OH).
84
What is the chemical formula for methanol?
The chemical formula for methanol is CH₃OH.
85
What is the chemical formula for ethanol?
The chemical formula for ethanol is C₂H₅OH.
86
What is the chemical formula for propanol?
The chemical formula for propanol is C₃H₇OH.
87
What is the chemical formula for butanol?
The chemical formula for butanol is C₄H₉OH.
88
What do we call a class of compounds that includes methanol ethanol propanol and butanol?
These compounds are classified as alcohols.
89
What products are formed when alcohols like methanol ethanol propanol and butanol burn in air?
They burn in air to produce carbon dioxide (CO₂) and water (H₂O).
90
What is the pH level of a solution where alcohols dissolve in water?
They dissolve in water to form a neutral solution with a pH of 7.
91
What happens when alcohols react with sodium?
When alcohols react with sodium they produce hydrogen gas (H₂) and a salt such as sodium ethoxide (C₂H₅ONa).
92
What do alcohols produce when they react with oxidizing agents?
Alcohols react with oxidizing agents to form carboxylic acids.
93
What are some common uses for methanol?
Methanol is used as a chemical feedstock in anti-freeze and to make biodiesel.
94
What are some common uses for ethanol?
Ethanol is the main alcohol in alcoholic drinks and it is also used as a solvent and fuel.
95
Can methanol ethanol propanol and butanol be used as fuels?
Yes all four can be used as fuels.
96
How is ethanol produced from sugar?
Ethanol can be produced by the fermentation of sugar with yeast using renewable sources.
97
What are the optimal conditions for the fermentation of sugar to produce ethanol?
The optimal conditions are about 35°C anaerobic (without oxygen) and the presence of yeast enzyme catalyst.
98
What are the products of the fermentation of sugar?
The products of the fermentation of sugar are ethanol and carbon dioxide.
99
What is ethanoic acid?
Ethanoic acid is a member of the carboxylic acids.
100
What is the functional group of carboxylic acids?
The functional group of carboxylic acids is COOH.
101
List the first four members of the carboxylic acid series and their structural formulas.
1. Methanoic acid: HCOOH
102
2. Ethanoic acid: CH3COOH
103
3. Propanoic acid: C2H5COOH
104
4. Butanoic acid: C3H7COOH.
105
What is the general characteristic of carboxylic acids when dissolved in water?
Carboxylic acids dissolve in water to produce acidic solutions with a pH less than 7.
106
What happens when carboxylic acids react with metal carbonates?
When carboxylic acids react with metal carbonates they produce carbon dioxide (which turns limewater cloudy) a salt and water.
107
What are the products of the reaction between carboxylic acids and alcohols in the presence of an acid catalyst?
The reaction between carboxylic acids and alcohols in the presence of an acid catalyst produces esters.
108
Do carboxylic acids ionize completely in solution? Why or why not?
Carboxylic acids do not ionize completely in solutions; they only partially disassociate to release hydrogen ions (H+) making them weak acids.
109
How does the acidity of carboxylic acids compare to strong acids of the same concentration?
Carboxylic acids are less acidic than strong acids of the same concentration due to their partial ionization.
110
What is the pH range of solutions of carboxylic acids?
The pH of solutions of carboxylic acids is typically less than 7.
111
What is the role of the acid catalyst in the reaction between carboxylic acids and alcohols?
The acid catalyst facilitates the esterification reaction between carboxylic acids and alcohols promoting the formation of esters.
112
Give an example of a carboxylic acid and its common use. What is methanoic acid also known as?
Methanoic acid is also known as formic acid. It is commonly used in the leather industry and as a preservative.
113
What is ethanoic acid commonly referred to and what is its primary use?
Ethanoic acid is commonly referred to as acetic acid. Its primary use is as a food preservative and in vinegar.
114
Describe the nature and properties of butanoic acid. Include its structural formula and physical state at room temperature.
Butanoic acid (C3H7COOH) is a carboxylic acid known for its unpleasant odor resembling that of rancid butter. It is a colorless liquid at room temperature.
115
What is the significance of the 'Higher Tier' content mentioned in the notes?
The content in bold is for Higher Tier only indicating that this information is specifically intended for students studying at a higher level of understanding in chemistry.
116
What type of reaction occurs during esterification and why is it important in organic chemistry?
Esterification is a condensation reaction between a carboxylic acid and an alcohol resulting in the formation of an ester and water. It is important in organic chemistry because esters are widely used in food flavorings fragrances and as solvents.
117
What is polymerisation?
Polymerisation is the process in which many small molecules known as monomers join together to form a large molecule called a polymer.
118
What type of polymerisation do alkenes undergo to produce polyethene and polypropene?
Alkenes undergo addition polymerisation to produce polymers such as polyethene and polypropene.
119
What is the distinguishing feature of addition polymerisation?
In addition polymerisation the repeat unit of the polymer has the same atoms as the original monomer and no other molecule is formed during the reaction.
120
How is the structure of a polymer represented?
When drawing a polymer it is important to show the bonds coming off the carbon atoms (Cs) outside of the brackets. The 'n' in the formula indicates that there are large numbers of these monomers joined together.
121
What characterizes condensation polymerisation?
Condensation polymerisation involves monomers that have two functional groups and during the reaction small molecules such as water are typically lost classifying the reactions as condensation reactions.
122
What are the simplest polymers produced through condensation polymerisation?
The simplest polymers produced from condensation polymerisation are created from two different monomers each having two of the same functional groups.
123
What type of functional groups can be involved in condensation polymerisation?
Condensation polymerisation can involve various functional groups but common examples include carboxylic acid functional groups and alcohol functional groups.
124
What is an example of a polyester formed by condensation polymerisation?
An example of a polyester is formed from one monomer containing two carboxylic acid functional groups and another monomer containing two alcohol functional groups.
125
What are amino acids and what is their significance in polymerisation?
Amino acids are organic compounds that contain both an amine group and a carboxylic acid group and they can be used to form proteins through polymerisation.
126
What is the difference between addition and condensation polymerisation?
The key difference is that addition polymerisation does not involve the loss of any small molecules and the repeat units are identical to the monomers while condensation polymerisation involves the loss of small molecules such as water and often forms different repeat units based on the monomers involved.
127
What are functional groups in a molecule?
Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. They influence the physical and chemical properties of the compounds.
128
What is an amine group?
An amine group is a functional group that contains nitrogen atom bonded to hydrogen atoms or alkyl or aryl groups. The general structure is -NH2 (primary amine) -NHR (secondary amine) or -NR2 (tertiary amine). Amines can act as bases and nucleophiles.
129
What is a carboxylic acid group?
A carboxylic acid group is a functional group characterized by a carbon atom double-bonded to an oxygen atom (carbonyl) and also bonded to a hydroxyl group (-OH). The general structure is -COOH. Carboxylic acids are known for their acidic properties.
130
What is condensation polymerization?
Condensation polymerization is a chemical process where monomers join together to form a polymer releasing small molecules as byproducts (usually water). This type of reaction is essential in forming polymers such as polypeptides and polyesters.
131
How do polypeptides form from amine and carboxylic acid groups?
Polypeptides form when amino acids which contain an amine group and a carboxylic acid group undergo condensation polymerization. The amine group of one amino acid reacts with the carboxylic acid group of another resulting in a peptide bond and the release of a water molecule.
132
What are amino acids?
Amino acids are organic compounds that serve as the building blocks of proteins. They contain both amine (-NH2) and carboxylic acid (-COOH) functional groups along with a distinctive side chain (R group) that determines the identity of the amino acid.
133
What is the significance of proteins in biological systems?
Proteins play critical roles in biological systems including serving as enzymes structural components signaling molecules transportation carriers and antibodies. They are essential for the function structure and regulation of the body's cells tissues and organs.
134
What is DNA and its function?
DNA (deoxyribonucleic acid) is a large complex molecule essential for all forms of life. It encodes the genetic instructions necessary for the development functioning growth and reproduction of living organisms and many viruses.
135
What are nucleotides?
Nucleotides are the monomers that make up nucleic acids like DNA and RNA. Each nucleotide consists of three components: a nitrogenous base (adenine thymine cytosine or guanine) a five-carbon sugar (deoxyribose in DNA) and a phosphate group.
136
What is the structure of DNA?
DNA has a double helix structure composed of two long strands of nucleotides wound around each other. The backbone of each strand is made up of alternating sugar and phosphate groups. The nitrogenous bases pair specifically (A with T C with G) through hydrogen bonding.
137
What are some other naturally occurring polymers important for life?
Other naturally occurring polymers include: 1) Proteins - composed of amino acids. 2) Starch - a carbohydrate composed of glucose units serving as an energy storage polysaccharide in plants. 3) Cellulose - a structural polysaccharide composed of glucose units providing rigidity in plant cell walls.
138
How do different amino acids contribute to protein diversity?
Different amino acids can be combined in various sequences to produce proteins with unique structures and functions. The specific sequence of amino acids in a polypeptide chain determines the protein's three-dimensional shape and its specific biological activity.
