1
Q
What is the simplest whole-number ratio of atoms of each element in a compound called?
A
Empirical formula
It shows the simplest ratio of atoms present.
2
Q
What formula shows the actual number of atoms of each element in a molecule?
A
Molecular formula
For example, glucose has molecular formula C6H12O6.
3
Q
Fill in the blank:
A formula showing the arrangement of atoms and bonds in a molecule is called the _______ formula.
A
structural
It indicates how atoms are connected.
4
Q
True or False:
A displayed formula shows every atom and bond in a molecule.
A
True
All covalent bonds are shown explicitly.
5
Q
What type of formula uses lines to represent carbon–carbon bonds and omits most hydrogen atoms?
A
Skeletal formula
Carbon atoms are implied at the ends and intersections of lines.
6
Q
True or False:
Skeletal formulas normally show all hydrogen atoms attached to carbon.
A
False
Hydrogens attached to carbon are usually omitted.
7
Q
Fill in the blank:
A family of organic compounds with the same functional group is called a _______ series.
A
homologous
Members differ by a repeating –CH2– unit.
8
Q
What feature is common to all members of a homologous series?
A
Same functional group
This leads to similar chemical reactions.
9
Q
True or False:
Members of a homologous series show a gradual change in physical properties.
A
True
For example, boiling point increases with chain length.
10
Q
What naming system is used internationally for naming organic compounds?
A
IUPAC nomenclature
The International Union of Pure and Applied Chemistry sets the rules.
11
Q
Fill in the blank:
In IUPAC naming, the longest continuous chain of carbon atoms determines the _______ name.
A
parent
The parent chain forms the base name of the compound.
12
Q
According to A-level requirements, organic compounds should be named using chains of up to how many carbon atoms?
A
Six
Students must apply IUPAC rules to chains and rings up to six carbons.
13
Q
What term describes the step-by-step pathway showing how reactants form products in an organic reaction?
A
Reaction mechanism
It shows the movement of electrons and formation/breaking of bonds.
14
Q
What type of species has an unpaired electron and is involved in certain organic reactions?
A
Radical
Radicals are highly reactive species with a single unpaired electron.
15
Q
Fill in the blank:
In radical mechanisms, the unpaired electron is represented by a _______.
A
dot
A dot next to the atom symbol shows the radical.
16
Q
True or False:
Curly arrows are normally used to show electron movement in free-radical mechanisms.
A
False
Radical mechanisms usually use single dots rather than curly arrows.
17
Q
What type of arrow is used to show the movement of an electron pair in many organic mechanisms?
A
Curly arrow
The arrow starts at the electron pair and points to where the electrons move.
18
Q
True or False:
A curly arrow can start from a lone pair of electrons to show bond formation.
A
True
This represents donation of an electron pair to form a covalent bond.
19
Q
Fill in the blank:
When a covalent bond breaks in a mechanism, the curly arrow starts from the _______.
A
bond
This indicates the electrons move away from that bond.
20
Q
What does a curly arrow represent in an organic reaction mechanism?
A
Movement of an electron pair
It shows how electrons rearrange during the reaction.
21
Q
True or False:
Reaction mechanisms must show the structures of all species involved in each step.
A
True
Each intermediate and transition step should be represented.
22
Q
What must be written for each step in a free-radical mechanism besides structures?
A
Balanced equation
Each stage (initiation, propagation, termination) must balance atoms.
23
Q
Fill in the blank:
The formation of a new covalent bond occurs when an electron _______ is shared between atoms.
A
pair
Curly arrows illustrate this movement of electron pairs.
24
Q
Why are mechanisms useful in organic chemistry?
A
Explains how reactions occur.
They show the detailed sequence of bond breaking and bond forming.
25
What term describes **compounds with the same molecular formula** but different **structural arrangements**?
Isomers
## Footnote
Isomers share a formula but differ in structure or spatial arrangement.
26
What type of **isomerism** occurs when **atoms are connected in different ways** within molecules?
Structural isomerism
## Footnote
These isomers differ in the arrangement of atoms in the molecule.
27
# Fill in the blank:
**Structural isomers** have the same molecular formula but different _\_\_\_\_\_\_ formulas.
structural
## Footnote
The atoms are connected differently.
28
# True or False:
**Chain isomerism** occurs when the **carbon skeleton differs** between molecules.
True
## Footnote
For example, straight-chain vs branched-chain hydrocarbons.
29
What type of **structural isomerism** occurs when the **functional group** is located in different positions?
Position isomerism
## Footnote
The carbon skeleton remains the same but the group moves position.
30
# True or False:
**Functional group isomers** have the same functional group but in different positions.
False
## Footnote
Functional group isomers contain different functional groups.
31
# Fill in the blank:
Isomers that differ only in the **spatial arrangement of atoms** are called _\_\_\_\_\_\_ isomers.
stereoisomers
## Footnote
The bonding arrangement remains the same.
32
What type of **stereoisomerism** occurs due to **restricted rotation around a C=C double bond**?
E–Z isomerism
## Footnote
The double bond prevents free rotation of substituents.
33
# True or False:
**E–Z isomerism** can occur around **single carbon–carbon bonds**.
False
## Footnote
Single bonds rotate freely so stereoisomerism does not occur.
34
# Fill in the blank:
The system used to assign **priorities** when determining E or Z configuration is the _\_\_\_\_\_\_ rules.
CIP
## Footnote
Cahn–Ingold–Prelog priority rules determine substituent ranking.
35
In **E–Z notation**, what does the letter **E** indicate about the highest priority groups?
Opposite sides
## Footnote
E comes from the German “entgegen,” meaning opposite.
36
In **E–Z notation**, what does the letter **Z** indicate about the highest priority groups?
Same side
## Footnote
Z comes from the German “zusammen,” meaning together.
37
What is the functional group isomer of an **aldehyde**?
A ketone
38
What is the functional group isomer of a **ketone**?
An aldehyde
39
What is the functional group isomer of an **alcohol**?
An ether
40
What is the functional group isomer of an **ether**?
An alcohol
41
What is the functional group isomer of a **carboxylic acid**?
An ester
42
What is the functional group isomer of an **ester**?
A carboxylic acid
43
What type of **hydrocarbons** are **alkanes** classified as?
Saturated hydrocarbons
## Footnote
They contain only single carbon–carbon bonds.
44
What **natural resource** is the main source of **alkanes used as fuels**?
Crude oil
## Footnote
Also called petroleum, it is a complex mixture of hydrocarbons.
45
# Fill in the blank:
Crude oil is separated into fractions by _\_\_\_\_\_\_ distillation.
fractional
## Footnote
This process separates hydrocarbons based on boiling points.
46
# True or False:
**Alkanes** contain **carbon–carbon double bonds**.
False
## Footnote
Alkanes only contain single C–C bonds.
47
What **property** allows hydrocarbons in crude oil to be separated during **fractional distillation**?
Different boiling points
## Footnote
Larger molecules have stronger intermolecular forces and higher boiling points.
48
# True or False:
**Short-chain alkanes** have **lower boiling points** than long-chain alkanes.
True
## Footnote
Smaller molecules have weaker London dispersion forces.
49
# Fill in the blank:
The **boiling point of alkanes** increases as the length of the carbon _\_\_\_\_\_\_ increases.
chain
## Footnote
Longer chains have stronger intermolecular forces.
50
What is a **fraction** in **crude oil processing**?
Group of hydrocarbons with similar boiling points.
## Footnote
Each fraction condenses at a different level in the column.
51
# True or False:
**Larger hydrocarbons** condense **higher up** in the fractionating column.
False
## Footnote
Larger molecules condense lower in the column where temperatures are higher.
52
Why are **hydrocarbons heated** before entering the fractionating column?
To vaporise them.
## Footnote
The vapours then rise and condense at different temperatures.
53
# Fill in the blank:
In **fractional distillation**, cooler temperatures are found toward the _\_\_\_\_\_\_ of the column.
top
## Footnote
Temperature decreases as vapours rise up the column.
54
Why is **crude oil** described as a **mixture rather than a pure substance**?
Contains many hydrocarbons.
## Footnote
It consists mainly of different alkane molecules of varying chain lengths.
55
What **process** breaks **long-chain alkanes** into smaller molecules?
Cracking
## Footnote
Cracking breaks C–C bonds to produce smaller hydrocarbons.
56
What type of **bond** is broken during the **cracking of alkanes**?
Carbon–carbon single bond
## Footnote
Breaking these bonds produces smaller alkanes and alkenes.
57
# Fill in the blank:
**Cracking** converts long-chain hydrocarbons into _\_\_\_\_\_\_ hydrocarbons.
shorter
## Footnote
Smaller molecules are often more useful as fuels or chemical feedstocks.
58
# True or False:
**Thermal Cracking** often produces **alkenes as well as alkanes**.
True
## Footnote
The process commonly forms unsaturated hydrocarbons.
59
What type of **cracking** occurs at **high temperature and high pressure**?
Thermal cracking
## Footnote
This method produces a high proportion of alkenes.
60
# True or False:
**Catalytic cracking** requires a **catalyst such as a zeolite**.
True
## Footnote
Zeolite catalysts provide active sites for the reaction.
61
# Fill in the blank:
**Catalytic cracking** is carried out at high temperature and _\_\_\_\_\_\_ pressure.
slight
## Footnote
It operates at lower pressure than thermal cracking.
62
What useful **product** is mainly produced by **catalytic cracking** for transportation?
Motor fuels
## Footnote
This helps produce petrol and other useful fuels.
63
# True or False:
**Catalytic cracking** is commonly used to produce **aromatic hydrocarbons**.
True
## Footnote
These are important feedstocks in the petrochemical industry.
64
Why is **cracking economically important** in the petrochemical industry?
Matches supply and demand.
## Footnote
It converts surplus long-chain hydrocarbons into more valuable shorter ones.
65
# Fill in the blank:
**Cracking** increases the supply of smaller hydrocarbons such as _\_\_\_\_\_\_ used in polymer production.
alkenes
## Footnote
Alkenes are important raw materials for making plastics.
66
Why are **shorter-chain hydrocarbons** more valuable than longer ones?
They are more useful fuels.
## Footnote
Shorter-chain hydrocarbons are more volatile and burn efficiently in engines.
67
What is the **main use** of **alkanes** in modern society?
Fuels
## Footnote
Alkanes release energy when combusted and are widely used for heating and transport.
68
What type of **reaction** occurs when **alkanes react with oxygen** to release energy?
Combustion
## Footnote
Combustion reactions are exothermic oxidation reactions.
69
# Fill in the blank:
Complete **combustion of alkanes** produces carbon _\_\_\_\_\_\_ and water.
dioxide
## Footnote
When sufficient oxygen is present the products are CO2 and H2O.
70
# True or False:
**Incomplete combustion** occurs when there is a **limited supply of oxygen**.
True
## Footnote
This leads to formation of CO or carbon instead of CO2.
71
What **toxic gas** is formed during **incomplete combustion of hydrocarbons**?
Carbon monoxide
## Footnote
CO binds strongly to haemoglobin and prevents oxygen transport.
72
# True or False:
**Incomplete combustion** can produce **solid carbon (soot)**.
True
## Footnote
Soot forms when hydrocarbons burn with insufficient oxygen.
73
# Fill in the blank:
**Nitrogen oxides** produced in internal combustion engines are commonly called _\_\_\_\_\_\_.
NOx
## Footnote
These gases contribute to air pollution and acid rain.
74
What **device** is used in **car exhaust systems** to reduce harmful emissions?
Catalytic converter
## Footnote
It converts CO, NOx and hydrocarbons into less harmful gases.
75
# True or False:
**Catalytic converters** reduce **carbon monoxide to carbon dioxide**.
True
## Footnote
They also reduce nitrogen oxides to nitrogen.
76
What **pollutant** is formed when **sulfur impurities in fuels** are burned?
Sulfur dioxide
## Footnote
SO2 contributes to acid rain and air pollution.
77
# Fill in the blank:
**Sulfur dioxide** can be removed from flue gases using **calcium oxide** or calcium _\_\_\_\_\_\_.
carbonate
## Footnote
These substances react with SO2 to form calcium sulfite or sulfate.
78
Why are **calcium oxide and calcium carbonate** used to remove **sulfur dioxide from flue gases**?
Neutralisation reaction
## Footnote
They react with acidic SO2 to form solid calcium salts.
79
What type of **reaction** occurs when **methane reacts with chlorine** in ultraviolet light?
Free-radical substitution
## Footnote
A hydrogen atom in methane is replaced by a chlorine atom.
80
What highly reactive **species with an unpaired electron** is formed during the **chlorination of methane**?
Radical
## Footnote
Radicals are produced during the initiation step.
81
# Fill in the blank:
In **free-radical mechanisms**, an unpaired electron is represented by a _\_\_\_\_\_\_.
dot
## Footnote
The dot indicates the presence of a single unpaired electron.
82
# True or False:
**Chlorination of methane** requires **ultraviolet light** to start the reaction.
True
## Footnote
UV light provides energy to break the Cl–Cl bond homolytically.
83
What is the **first stage** of the **free-radical substitution mechanism** called?
Initiation
## Footnote
In this step radicals are first formed.
84
# True or False:
The **propagation step** forms new radicals that continue the **chain reaction**.
True
## Footnote
Each step generates another radical allowing the reaction to continue.
85
# Fill in the blank:
In the **initiation step**, chlorine molecules split to form two chlorine _\_\_\_\_\_\_.
radicals
## Footnote
Cl2 → 2Cl· under UV light.
86
What is the name of the **stage** where radicals react together and remove radicals from the reaction?
Termination
## Footnote
Two radicals combine to form a stable molecule.
87
# True or False:
**Propagation steps** maintain the **chain reaction** by regenerating radicals.
True
## Footnote
Radicals produced in propagation keep the reaction going.
88
# Fill in the blank:
In the **first propagation step**, a chlorine radical reacts with methane to form _\_\_\_\_\_\_ radical.
methyl
## Footnote
CH4 + Cl· → CH3· + HCl.
89
What is the **main organic product** formed when methane reacts with chlorine once?
Chloromethane
## Footnote
CH3Cl forms when a hydrogen atom is replaced by chlorine.
90
Why can **further substitution** occur during **methane chlorination**?
Radicals continue reacting
## Footnote
Additional hydrogens can be replaced forming dichloromethane and other products.
91
Give the **equation** for the **second propagation step** in **methane chlorination**.
CH₃· + Cl₂ → CH₃Cl + Cl·
92
What type of **bond** is present between **carbon and halogen atoms** in halogenoalkanes?
Polar covalent bond
## Footnote
The electronegative halogen pulls electron density away from carbon.
93
What type of **reaction** occurs when a **halogenoalkane reacts with a nucleophile**?
Nucleophilic substitution
## Footnote
The nucleophile replaces the halogen atom.
94
# Fill in the blank:
A species that **donates a lone pair of electrons** to form a bond is called a _\_\_\_\_\_\_.
nucleophile
## Footnote
Nucleophiles are electron-pair donors.
95
# True or False:
**Aqueous Hydroxide ions** can act as **nucleophiles** in substitution reactions.
True
## Footnote
OH- attacks the electron-deficient carbon atom.
96
What **product** forms when a **halogenoalkane reacts with hydroxide ions**?
Alcohol
## Footnote
The OH- replaces the halogen atom.
97
# True or False:
**Cyanide ions** reacting with **halogenoalkanes** increase the carbon chain length.
True
## Footnote
CN- introduces an additional carbon atom to the molecule.
98
# Fill in the blank:
Reaction of a **halogenoalkane with ammonia** forms a _\_\_\_\_\_\_.
amine
## Footnote
NH3 replaces the halogen to form an amine group.
99
Why is the **carbon atom** in a halogenoalkane susceptible to **nucleophilic attack**?
Partial positive charge
## Footnote
The polar C–X bond leaves carbon slightly electron deficient.
100
# True or False:
The **strength of the carbon–halogen bond** affects the **rate of nucleophilic substitution**.
True
## Footnote
Weaker bonds break more easily and react faster.
101
# Fill in the blank:
As the **carbon–halogen bond enthalpy** decreases, the **rate of reaction** generally _\_\_\_\_\_\_.
increases
## Footnote
Iodoalkanes react faster than chloroalkanes. Bromoalkanes are in the middle.
102
Which **halogenoalkane** typically reacts fastest in **nucleophilic substitution reactions**?
Iodoalkane
## Footnote
The C–I bond is weakest among common halogenoalkanes. This is because the bond length is greater thus the nuclear attraction to the outer electrons is weaker.
103
Why do **iodoalkanes** react faster than **chloroalkanes** in substitution reactions?
Weaker carbon–halogen bond
## Footnote
Lower bond enthalpy makes bond breaking easier.
104
What type of **reaction** forms an **alkene from a halogenoalkane** by removing a hydrogen halide?
Elimination
## Footnote
A hydrogen atom and a halogen atom are removed from adjacent carbons.
105
What type of **organic product** is formed during **elimination of a halogenoalkane**?
Alkene
## Footnote
The reaction creates a carbon–carbon double bond.
106
# Fill in the blank:
During **elimination**, a halogenoalkane loses hydrogen and a _\_\_\_\_\_\_ atom.
halogen
## Footnote
The removed atoms combine to form HX.
107
# True or False:
**Elimination and substitution reactions** can occur simultaneously in halogenoalkane reactions.
True
## Footnote
The reaction conditions determine which pathway dominates.
108
What **reagent** is commonly used to cause **elimination in halogenoalkanes**?
Ethanolic Potassium hydroxide
## Footnote
Usually used in ethanolic solution to favour elimination. Ethanolic means dissolved in alcohol.
109
# True or False:
**Hydroxide ions** can act as both **nucleophiles and bases**.
True
## Footnote
They can attack carbon (substitution) or remove a proton (elimination).
110
# Fill in the blank:
In **elimination reactions**, the ethanolic hydroxide ion acts as a _\_\_\_\_\_\_ by removing a proton.
base
## Footnote
It removes H+ from a neighbouring carbon atom.
111
What **role** does aqueous hydroxide play in **nucleophilic substitution reactions**?
Nucleophile
## Footnote
It donates a lone pair to form a new bond with carbon.
112
# True or False:
In **elimination reactions**, the hydroxide ion removes a **hydrogen atom as H+**.
True
## Footnote
This leads to formation of a double bond between carbons.
113
# Fill in the blank:
The **elimination of HBr from 2-bromopropane** forms the alkene _\_\_\_\_\_\_.
propene
## Footnote
A double bond forms between two carbon atoms.
114
Why can **potassium hydroxide** cause both **substitution and elimination reactions**?
Dual role
## Footnote
OH- can act either as a nucleophile or a base depending on conditions.
115
What **structural change** occurs in the organic molecule during **elimination**?
Double bond formation
## Footnote
Removal of HX allows formation of a C=C bond.
116
What **molecule** in the **upper atmosphere** absorbs harmful ultraviolet radiation?
Ozone
## Footnote
O3 absorbs UV radiation and protects living organisms from damage.
117
In which **layer of the atmosphere** is the **ozone layer** found?
Stratosphere
## Footnote
The ozone layer is located above the troposphere.
118
# Fill in the blank:
**Ozone molecules** contain _\_\_\_\_\_\_ oxygen atoms.
three
## Footnote
The chemical formula of ozone is O3.
119
# True or False:
**Ozone** protects life on Earth by absorbing **ultraviolet radiation**.
True
## Footnote
This prevents harmful UV rays from reaching the Earth’s surface.
120
What **compounds** were once widely used as **refrigerants and solvents** but damage the ozone layer?
Chlorofluorocarbons
## Footnote
These compounds are commonly called CFCs.
121
# True or False:
**Ultraviolet radiation** can break the **carbon–chlorine bonds in CFCs**.
True
## Footnote
This process forms chlorine radicals in the atmosphere.
122
# Fill in the blank:
When **CFC molecules break down**, they release chlorine _\_\_\_\_\_\_.
radicals
## Footnote
These radicals are highly reactive species with unpaired electrons.
123
What **role** do **chlorine radicals** play in ozone depletion?
Catalysts
## Footnote
They speed up ozone decomposition without being consumed.
124
# True or False:
**Chlorine radicals** are regenerated during **ozone destruction reactions**.
True
## Footnote
This allows one radical to destroy many ozone molecules.
125
# Fill in the blank:
In the reaction Cl· + O3 → ClO· + O2, ozone is converted into _\_\_\_\_\_\_.
oxygen
## Footnote
Ozone decomposes into molecular oxygen.
126
Why can a single **chlorine radical** destroy many **ozone molecules**?
Catalyst regeneration
## Footnote
The chlorine radical is reformed at the end of the reaction cycle. ClO· + O3 → 2O2 + Cl·
127
Why were **CFCs** eventually **banned in many countries**?
Scientific evidence
## Footnote
Research showed they were responsible for depletion of the ozone layer.
A-Level Chemistry (Edexcel)
flashcards
Decks in class (19)
# Cards
-
Topic 1: Atomic Structure and the Periodic Table72
-
Topic 2: Structure and Bonding90
-
Topic 3: Redox I17
-
Topic 4: Inorganic Chemistry and the Periodic Table90
-
Topic 5: Formulae, Equations and Amount of Substance47
-
Topic 6: Organic Chemistry I127
-
Topic 7: Modern Analytical Techniques I36
-
Topic 8: Energetics I62
-
Topic 9: Kinetics I55
-
Topic 10: Equilibrium I24
-
Topic 11: Equilibrium II12
-
Topic 12: Acid–Base Equilibria69
-
Topic 13: Energetics II27
-
Topic 14: Redox II46
-
Topic 15: Transition Metals134
-
Topic 16: Kinetics II24
-
Topic 17: Organic Chemistry II136
-
Topic 18: Organic Chemistry III155
-
Topic 19: Modern Analytical Techniques II26
