Question

8.10 Explain the value of bond dissociation energies and use bond dissociation energies in calculations

1. Explain how bond dissociation energies are used to determine the enthalpy change in a reaction.

2. Understand the limitations of using average bond dissociation energy values.

3. Calculate reaction enthalpies from bond dissociation energies

Answer 1

Band Dissociation Energy → Ha (9) Enthalpy change during the Breaking of Imole cat Bond of gaseous molecule into gaseous entom is known as Bond dissociation Energy, Example → 2H (2) дн° = Кн-н = Bond Emergy of H-H → It is used to Break the all Bonds to convert molecule into gaseous atom. Enthalpy of the Reaction from Bond dissociation Energy For A Reaction. AH E reactent E product Hg (8) QH (g) ДИ° (feng 'Bond Energy of (son, Bond Energy of Product + - Reactent DHO ΣΗ-Η Because in product theer is no-Bonds Present ® Limitation = Bond dissociation Energy Concept only Applicable for gascous moleates to Convert gagouy atom. →IN 23 (3) ΑΗ- Σο=ο AHO = ENEŃ 2009) N2187 CS Scanned with CamScanner

С (2) + ЧИt3) (2) Calculation of Enthalpy of Reaction in terms of Bond dissociation Energy. с Ич (2) t\ Ди“ 42c-И Hz (9) + O2 (3) - ное) N ди" = (х-и +} soze]- Глор., 43, 4 сі%) +2 Zо-н CS Scanned with CamScanner