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Question 800005
JEE Chemistry · Medium

Chemical Thermodynamics and Thermochemistry: Bond enthalpy MCQ

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Bond enthalpyMediumQuestion 800005

Question

ΔH_reaction using bond enthalpies = :
  1. A
    ΣBE(reactants) − ΣBE(products)
    Correct
  2. B
    ΣBE(products) − ΣBE(reactants)
  3. C
    ΣBE(reactants) + ΣBE(products)
  4. D
    Always negative

Correct answer

ΣBE(reactants) − ΣBE(products)

Explanation

ΔH_rxn = Σ(bond energies broken in reactants) − Σ(bond energies formed in products). Breaking bonds is endothermic (+), forming bonds is exothermic (−).

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