Bond Energy Worksheets by Olivia Hunter - Issuu - Free Printable

1. H-H + Cl-Cl → H-Cl + H-Cl
- Bonds broken: 1 H-H (436 kJ/mol), 1 Cl-Cl (242 kJ/mol)
- Bonds formed: 2 H-Cl (2 × 431 kJ/mol)
- ΔH_rxn = (436 + 242) - (2 × 431) = 678 - 862 = -184 kJ/mol

2. H₂C=C₂H₂ + F-F → H₃C-CH₂F
- Bonds broken: 1 C=C (614 kJ/mol), 1 F-F (155 kJ/mol)
- Bonds formed: 2 C-F (2 × 485 kJ/mol), 1 C-C (348 kJ/mol), 4 C-H (4 × 413 kJ/mol)
- ΔH_rxn = (614 + 155) - (2 × 485 + 348 + 4 × 413) = 769 - (970 + 348 + 1652) = 769 - 2970 = -2201 kJ/mol

3. H-C-O-H + H-C-O-H → H-C-O-C-H + H-O-H
- Bonds broken: 1 O-H (463 kJ/mol), 1 C-O (358 kJ/mol)
- Bonds formed: 1 C-O (358 kJ/mol), 1 O-H (463 kJ/mol)
- ΔH_rxn = (463 + 358) - (358 + 463) = 821 - 821 = 0 kJ/mol

4. H-C-Cl + O → C-Cl + H-Cl
- Bonds broken: 1 C-H (413 kJ/mol), 1 C-Cl (328 kJ/mol), 1 O=O (495 kJ/mol)
- Bonds formed: 1 C=O (799 kJ/mol), 1 C-Cl (328 kJ/mol), 1 H-Cl (431 kJ/mol)
- ΔH_rxn = (413 + 328 + 495) - (799 + 328 + 431) = 1236 - 1558 = -322 kJ/mol

5. H-C-H + O=O → O=C=O + H-O-H
- Bonds broken: 4 C-H (4 × 413 kJ/mol), 1 O=O (495 kJ/mol)
- Bonds formed: 2 C=O (2 × 799 kJ/mol), 2 O-H (2 × 463 kJ/mol)
- ΔH_rxn = (4 × 413 + 495) - (2 × 799 + 2 × 463) = (1652 + 495) - (1598 + 926) = 2147 - 2524 = -377 kJ/mol

6. H₂(g) + CO₂(g) → H₂O(g) + CO(g)
- Bonds broken: 1 H-H (436 kJ/mol), 2 C=O (2 × 799 kJ/mol)
- Bonds formed: 2 O-H (2 × 463 kJ/mol), 1 C≡O (1072 kJ/mol)
- ΔH_rxn = (436 + 1598) - (926 + 1072) = 2034 - 1998 = 36 kJ/mol

7. 2H₂O₂(g) → 2H₂O(g) + O₂(g)
- Bonds broken: 2 O-O (2 × 146 kJ/mol), 2 O-H (2 × 463 kJ/mol)
- Bonds formed: 4 O-H (4 × 463 kJ/mol), 1 O=O (495 kJ/mol)
- ΔH_rxn = (2 × 146 + 2 × 463) - (4 × 463 + 495) = (292 + 926) - (1852 + 495) = 1218 - 2347 = -1129 kJ/mol

8. CO(g) + 2H₂(g) → CH₃OH(g)
- Bonds broken: 1 C≡O (1072 kJ/mol), 2 H-H (2 × 436 kJ/mol)
- Bonds formed: 3 C-H (3 × 413 kJ/mol), 1 C-O (358 kJ/mol), 1 O-H (463 kJ/mol)
- ΔH_rxn = (1072 + 872) - (1239 + 358 + 463) = 1944 - 2060 = -116 kJ/mol

9. N₂(g) + 3H₂(g) → 2NH₃(g)
- Bonds broken: 1 N≡N (941 kJ/mol), 3 H-H (3 × 436 kJ/mol)
- Bonds formed: 6 N-H (6 × 391 kJ/mol)
- ΔH_rxn = (941 + 1308) - (6 × 391) = 2249 - 2346 = -97 kJ/mol

10. H₂(g) + C₂H₄(g) → C₂H₆(g)
- Bonds broken: 1 H-H (436 kJ/mol), 1 C=C (614 kJ/mol)
- Bonds formed: 1 C-C (348 kJ/mol), 4 C-H (4 × 413 kJ/mol)
- ΔH_rxn = (436 + 614) - (348 + 1652) = 1050 - 2000 = -950 kJ/mol

11. 2C₂H₆(g) + 7O₂(g) → 4CO₂(g) + 6H₂O(g)
- Bonds broken: 2 C-C (2 × 348 kJ/mol), 12 C-H (12 × 413 kJ/mol), 7 O=O (7 × 495 kJ/mol)
- Bonds formed: 8 C=O (8 × 799 kJ/mol), 12 O-H (12 × 463 kJ/mol)
- ΔH_rxn = (2 × 348 + 12 × 413 + 7 × 495) - (8 × 799 + 12 × 463) = (696 + 4956 + 3465) - (6392 + 5556) = 9117 - 11948 = -2831 kJ/mol

12. CH₄(g) + 3Cl₂(g) → CHCl₃(g) + 3HCl(g)
- Bonds broken: 4 C-H (4 × 413 kJ/mol), 3 Cl-Cl (3 × 242 kJ/mol)
- Bonds formed: 1 C-Cl (328 kJ/mol), 3 C-H (3 × 413 kJ/mol), 3 H-Cl (3 × 431 kJ/mol)
- ΔH_rxn = (4 × 413 + 3 × 242) - (328 + 3 × 413 + 3 × 431) = (1652 + 726) - (328 + 1239 + 1293) = 2378 - 2860 = -482 kJ/mol

13. HCN(g) + 2H₂(g) → CH₃NH₂(g)
- Bonds broken: 1 C≡N (891 kJ/mol), 2 H-H (2 × 436 kJ/mol)
- Bonds formed: 3 C-H (3 × 413 kJ/mol), 1 C-N (293 kJ/mol), 2 N-H (2 × 391 kJ/mol)
- ΔH_rxn = (891 + 872) - (3 × 413 + 293 + 2 × 391) = 1763 - (1239 + 293 + 782) = 1763 - 2314 = -551 kJ/mol