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Problem: Consider the reaction: H2(g) + I2(s) → 2 HI(g)Without doing a calculation, predict whether your estimate ΔH using bond enthalpies is more negative or less negative than the true reaction enthalpy.Average Bond Enthalpies (kJ/mol)C-H 413N-H 391O-H 463F-F 155C-C 348N-N 163O-O 146C=C 614N-O 201O=O 495Cl-F 253C-N 293N-F 272O-F 190Cl-Cl 242C-O 358N-Cl 200O-Cl 203Br-F 237C=O 799N-Br 243O-I 234Br-Cl 218C-F 485H-H 436Br-Br 193C-Cl 328H-F 567C-Br 276H-Cl 431I-Cl 208C-I 240H-Br 366I-Br 175H-I 299I-I 151

FREE Expert Solution

To calculate the ΔH°rxn using bond energies, we’re going to use the following equation:

H°rxn=Hbond reactants-Hbond products


Bond energy or bond enthalpy → enthalpy change (ΔH) for breaking a particular bond in one mole of a gaseous substance

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Problem Details

Consider the reaction: H2(g) + I2(s) → 2 HI(g)

Without doing a calculation, predict whether your estimate ΔH using bond enthalpies is more negative or less negative than the true reaction enthalpy.

Average Bond Enthalpies (kJ/mol)

C-H 413N-H 391O-H 463F-F 155
C-C 348N-N 163O-O 146
C=C 614N-O 201O=O 495Cl-F 253
C-N 293N-F 272O-F 190Cl-Cl 242
C-O 358N-Cl 200O-Cl 203Br-F 237
C=O 799N-Br 243O-I 234Br-Cl 218
C-F 485H-H 436
Br-Br 193
C-Cl 328H-F 567

C-Br 276H-Cl 431
I-Cl 208
C-I 240H-Br 366
I-Br 175

H-I 299
I-I 151



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