CHEM 219 MODULE 8 DETAILED
PRACTICE COLLECTION WITH ESSENTIAL
QUESTIONS AND CORRECT ANSWERS
◉ Initiation of Free Radicals
Answer: production of a radical species from a non-radical species
using heat or UV light
◉ Propagation of Free Radicals
Answer: reaction of a radical with a non-radical producing a new
radical species and continuing the chain reaction
◉ Termination of Free Radicals
Answer: reaction of 2 radicals with each other producing a non-
radical- no intermediate reactive = reaction stops
◉ chain transfer reaction
Answer: type of propagation step where a radical in one polymer
chain abstracts a hydrogen atom from a position in a different
polymer chain which causes branching in a growing polymer
chain
◉ Rates of the straight chain propagation steps versus the chain
transfer steps
, -Rates are controlled by stability of the intermediate radicals that
form as a product in each
Answer: what is chain transfer dependent on?
◉ Cation Chain-Growth Polymerization
Answer: best for substrates that can form stable carbocation
intermediates (typically unsubstituted substrates like bulky
alkenes or alkenes with electron-donating substituents)
◉ How is cation addition polymerization initiated?
Answer: By adding a strong acid to an alkene to form a
carbocation intermediate
◉ cation addition polymerization propagation
Answer: carbocation intermediate + new alkene monomer
molecule adds one unit to the polymer chain each time
◉ cation addition polymerization termination
Answer: terminates by the removal of a hydrogen atom from a
carbon atom adjacent to the positively charged carbon to form an
alkene (like in an elimination reaction)
◉ Anionic addition polymerization
Answer: a form of chain-growth polymerization or addition
polymerization that involves the polymerization of monomers
PRACTICE COLLECTION WITH ESSENTIAL
QUESTIONS AND CORRECT ANSWERS
◉ Initiation of Free Radicals
Answer: production of a radical species from a non-radical species
using heat or UV light
◉ Propagation of Free Radicals
Answer: reaction of a radical with a non-radical producing a new
radical species and continuing the chain reaction
◉ Termination of Free Radicals
Answer: reaction of 2 radicals with each other producing a non-
radical- no intermediate reactive = reaction stops
◉ chain transfer reaction
Answer: type of propagation step where a radical in one polymer
chain abstracts a hydrogen atom from a position in a different
polymer chain which causes branching in a growing polymer
chain
◉ Rates of the straight chain propagation steps versus the chain
transfer steps
, -Rates are controlled by stability of the intermediate radicals that
form as a product in each
Answer: what is chain transfer dependent on?
◉ Cation Chain-Growth Polymerization
Answer: best for substrates that can form stable carbocation
intermediates (typically unsubstituted substrates like bulky
alkenes or alkenes with electron-donating substituents)
◉ How is cation addition polymerization initiated?
Answer: By adding a strong acid to an alkene to form a
carbocation intermediate
◉ cation addition polymerization propagation
Answer: carbocation intermediate + new alkene monomer
molecule adds one unit to the polymer chain each time
◉ cation addition polymerization termination
Answer: terminates by the removal of a hydrogen atom from a
carbon atom adjacent to the positively charged carbon to form an
alkene (like in an elimination reaction)
◉ Anionic addition polymerization
Answer: a form of chain-growth polymerization or addition
polymerization that involves the polymerization of monomers
