Welcome to the Quiz!
This quiz contains 12 questions from a mix of 1 subtopics.
Which of the following conditions are necessary for halogens to react with alkanes?
high temperature
presence of a catalyst
high pressure
presence of ultraviolet light
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What type of reaction occurs when a halogen reacts with an alkane?
elimination
substitution
rearrangement
addition
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In the photochemical halogenation of alkanes, what is the role of ultraviolet light?
to break the carbon-hydrogen bond in the alkane
to stabilise the halogenoalkane product
to provide the activation energy to start the reaction
to prevent side reactions
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What happens during the initiation step of the free radical mechanism?
UV light produces reactive radicals
radicals join to form stable molecules
the alkane molecule is attacked by a halogen radical
radicals react in a chain reaction
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In the reaction between methane and chlorine, what is the primary product formed when there is an excess of methane?
trichloromethane
dichloromethane
tetrachloromethane
chloromethane
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What do the letters CFC stand for?
chlorofluorocycles
chlorofluorocompounds
chlorofluorocarbons
chlorofluorochains
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Which of the following is an example of a CFC?
CHCl3
CH2Cl2
CH3Cl
CCl3F
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What is the primary role of ozone in the upper atmosphere?
to trap heat and maintain Earth's temperature
to protect Earth from meteors and space debris
to absorb harmful ultraviolet radiation from the sun
to reflect visible light back to Earth
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How do CFCs damage the ozone layer?
they react directly with ozone molecules
they produce reactive chlorine radicals that catalyse ozone destruction
they trap heat in the upper atmosphere, causing ozone to decompose
they absorb ultraviolet light, preventing ozone formation
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What is one of the problems associated with using free radical halogenation to make specific halogenoalkane products?
low yield of the desired product
slow reaction rate
formation of multiple isomers
high energy consumption
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To maximise the yield of a desired halogenoalkane in a free radical halogenation reaction, which of the following should be used?
a catalyst
equal amounts of alkane and halogen
excess alkane relative to the halogen
excess halogen relative to the alkane
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In the propagation step of ozone depletion by CFCs, what is the overall reaction?
O2 + O ➔ 2O2
O3 ➔ O2
O3 + O ➔ 2O2
O3 + O2 ➔ 2O2
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