Bot GPT 4-o mini To determine which reaction is endothermic, we can analyze the energy involved in breaking and forming bonds for each reaction. The general rule is that if the energy of the bonds broken is greater than the energy of the bonds formed, the reaction is endothermic (absorbs heat), and if the energy of the bonds formed is greater than the energy of the bonds broken, the reaction is exothermic (releases heat).
Let's calculate the net energy change for each reaction based on the provided bond energies.
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C + O₂ → CO₂
- Bonds broken: 1 O=O (499 kJ/mol)
- Bonds formed: 2 C=O (1478 kJ/mol)
- Total energy broken = 499 kJ/mol
- Total energy formed = 1478 kJ/mol
- Net change = 499 - 1478 = -979 kJ/mol (exothermic)
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N₂ + O₂ → 2NO
- Bonds broken: 1 N≡N (946 kJ/mol), 1 O=O (499 kJ/mol)
- Bonds formed: 2 N=O (1214 kJ/mol)
- Total energy broken = 946 + 499 = 1445 kJ/mol
- Total energy formed = 1214 kJ/mol
- Net change = 1445 - 1214 = 231 kJ/mol (endothermic)
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S + O₂ → SO₂
- Bonds broken: 1 O=O (499 kJ/mol)
- Bonds formed: 2 S=O (1044 kJ/mol)
- Total energy broken = 499 kJ/mol
- Total energy formed = 1044 kJ/mol
- Net change = 499 - 1044 = -545 kJ/mol (exothermic)
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2CO + O₂ → 2CO₂
- Bonds broken: 2 C≡O (2148 kJ/mol) and 1 O=O (499 kJ/mol)
- Bonds formed: 4 C=O (2956 kJ/mol)
- Total energy broken = 2148 + 499 = 2647 kJ/mol
- Total energy formed = 2956 kJ/mol
- Net change = 2647 - 2956 = -309 kJ/mol (exothermic)
Based on these calculations, the only endothermic reaction is:
N₂ + O₂ → 2NO
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