Free Radical Sub

Question 1

what is homolytic fisson?

Answer 1

when a covalent bond breaks and the electrons go to each atoms.
product: free radical

Question 2

what is heterolytic fission?

Answer 2

when a covalent bond breaks and all the electrons go to one atom.
product: two ions (+/-)

Question 3

What is a free radical?

Answer 3

Any species that contains an unpaired electron

Question 4

What are the conditions required to form a free radical?

Answer 4

UV light

High temperature
T>450 degrees

Question 5

Which atoms are more likely to become free radicals?

Answer 5

The ones with lower bond enthalpy

Question 6

Example of mechanism of free radical substitution:

Answer 6

CH4+Cl2 —->CH3Cl+ HCl
Initiation: Cl2—>2Cl*
Propogation:
CH4+Cl—-> CH3+HCl *CH3+Cl2—>CH3Cl+Cl
Termination:
Cl+Cl—->Cl2
Cl +*CH3—>CH3Cl
CH3 +CH3—> CH3CH3

Question 7

what is a CFCs?

Answer 7

Chlorofluorocarbons

Question 8

Why were CFCs banned?

Answer 8

they form chlorine radicals.

Question 9

Mechanism for ozone:

Answer 9

2O3—>3O2
Initiation:
C2F4Cl2—>C2F4Cl +Cl
Propogation:
Cl+O3—>ClO+ O2
ClO* +O3—>2O2 +Cl*
Termination: free radical reacts with a free radical

Question 10

what are alternatives to CFCs?

Answer 10

hydrofluorocarbons
hydrocarbons

Question 11

why are the alternatives better than CFCs?

Answer 11

contain stronger bonds so don’t break under UV light.

cant produce Cl radicals.