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18.

The bond dissociation energy is the amount of energy required to break a bond

a)

so as to produce the more stable pair of ions

b) heterolytically
c)

homolytically

d) via hydrogenation
e)

none of the above

Definition: homolytically

19.

Given the bond dissociation energies below (in kcal/mol), calculate the overall 

D

H

°

 for the

following reaction:

(CH

3

)

3

CH    +     Br

2

(CH

3

)

3

CBr    +    HBr

(CH

3

)

3

C-H

91

(CH

3

)

3

C-Br

65

Br-Br

46

H-Br

88

CH3-Br

70

D

H

°

 =  -16 kcal/mol

Write chain propagation steps for the above bromination reaction.

(CH

3

)

3

CH    +     Br

(CH

3

)

3

CBr    +    Br

(CH

3

)

3

C    +     HBr

(CH

3

)

3

C    +     Br

2

End of Part 1