A) Estimate the heat released when ethene (CH2=CH2 ) reacts with HBr to give CH3CH2Br.

Bond enthalpies are

C--H : 412 kJ/mol; C--C : 348 kJ/mol

C=C : 612 kJ/mol; C--Br : 276 kJ/mol;

Br--Br : 193 kJ/mol; H--Br : 366 kJ/mol.

1. 470 kJ/mol

2. 200 kJ/mol

3. 58 kJ/mol

4. 1036 kJ/mol

5. 424 kJ/mol

B) Given the standard heats of reaction Reaction ?H0 M(s) + 2 X2(g) → MX4(g) -133.7 kJ/mol X2(g) → 2 X(g) +347.3 kJ/mol M(g) → M(s) -27.1 kJ/mol calculate the average bond energy for a single M X bond.

Answer in units of kJ/mol.

(Note: This question was submitted 2 days ago but haven't gotten the answer yet)