WorksheetsAlkanes and alkenes
Total questions: 27
Worksheet time: 21mins
Which of the following shows the structure of ethene?
Methane reacts with chlorine in substitution reaction. Which of these is an essential condition?
An acid catalyst
A low temperature
UV light
A low pressure
Alkanes react with excess oxygen to form
carbon dioxide and water
salt and water
carbon monoxide and soot
metal hydroxide and hydrogen
Possible products of INCOMPLETE combustion
Carbon (C)
Carbon Monoxide (CO)
Carbon Dioxide (CO2)
Water (H2O)
If an alkene has 20 carbon atoms, how many hydrogen atoms will it have?
20
22
40
42
What is cracking?
A process that turns long chain hydrocarbons into short chain hydrocarbons
A process that turns short chain hydrocarbons into long chain hydrocarbons
Why do we use cracking to get petrol?
The supply of petrol from cracking is larger than the demand
The supply of petrol from fractional distillation is larger than the demand
The supply of petrol from fractional distillation is smaller than the demand
The supply of petrol from cracking is smaller than the demand
What type of reaction is cracking?
Addition
Displacement
Thermal decomposition
Neutralisation
What is the test for alkenes?
Adding bromine water, if alkene is present it will turn orange
Adding bromine water, if alkene is present it will turn colourless
Adding bromine water, if alkane is present it will turn orange
Adding bromine water, if alkane is present it will turn colourless
In the electrophilic addition mechanism, what must the curly arrows show?
The movement of a single electron
The movement of a pair of electrons
The movement of protons
The movement of neutrons
What is the bond angle in a planar arrangement of an alkene molecule?
90°
109.5°
120°
180°
What rule is used to determine the priority of groups in E/Z isomers?
Markovnikov's rule
Hund's rule
Cahn-Ingold-Prelog (CIP) priority rules
Pauli exclusion principle
Why are alkenes more reactive than alkanes?
Due to the presence of a C-H bond
Due to the presence of a C-C single bond
Due to the presence of a C=C bond
Due to the presence of a C-O bond
Why is the alkene double bond, C=C, susceptible to attack by electrophiles?
Because it is an area of high electron density
Because it is an area of low electron density
Because it is an area of high proton density
Because it is an area of low proton density
Why is a hydrogen halide molecule polar?
Because the hydrogen and halogen atoms have different electronegativities
Because the hydrogen and halogen atoms have the same electronegativity
Because the hydrogen atom is larger than the halogen atom
Because the halogen atom is larger than the hydrogen atom
In the electrophilic addition of hydrogen bromide (HBr) to an alkene, what role does the H atom play?
It acts as an electrophile by accepting a pair of electrons from the C=C bond in the alkene
It acts as a nucleophile by donating a pair of electrons to the C=C bond in the alkene
It acts as a catalyst
It acts as a solvent
What is formed when the H-Br bond breaks heterolytically during electrophilic addition?
A Br⁻ ion
A H⁺ ion
A Br⁺ ion
A H⁻ ion
According to Markownikoff's rule, where does the halogen end up in an electrophilic addition reaction of a hydrogen halide (HX) to an alkene?
On the least substituted carbon atom
On the most substituted carbon atom
On the carbon atom with the least hydrogen atoms
On the carbon atom with the most hydrogen atoms
What is a free radical?
An atom or molecule with an unpaired electron
An atom or molecule with a paired electron
A molecule with a double bond
A stable molecule with no electrons
Which of the following is necessary to initiate the formation of halogenoalkanes?
Ultraviolet light
Microwave radiation
Infrared light
Visible light
What is the first step in the free radical substitution mechanism?
Propagation
Termination
Initiation
Condensation
What is the process called when a bond breaks equally and each atom takes one electron?
Electrolysis
Homolytic fission
Hydrolysis
Heterolytic fission
Which of the following is a possible termination step in free radical substitution?
A free radical splitting into two atoms
Formation of a new free radical
A free radical reacting with a stable molecule
Two free radicals reacting to form a stable molecule
