Question

Some bond energies are listed below
C-H bond 410kJ/mol
C-Cl bond. 340
Cl-Cl bond. 244
Br-Br bond. 193
These bond energies relate to the following
P. Br2 ->. 2Br
Q. 2Cl ->. Cl2
R. Ch3 + Cl ->. CH3Cl
S. CH4 ->. CH3 + H
What is the order of enthalpy changes of these reactions from negative to most positive?

Answer 1

To calculate the enthalpy change of the reaction you have to use the data given in the following manner.
Take the easy one, Br2--> 2Br. One Br-Br bond is being broken so the enthalpy change = Bond diss energy. In Ch3+Cl, it is the opposite of bond dissociation, i.e. - Bond Diss.
Can you work through the rest now?

Answer 2

No, I really didn't get it -.-

Answer 3

Help me out please!