Ch.9 - Bonding & Molecular StructureWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Bond Energy

See all sections
Sections
Chemical Bonds
Lattice Energy
Lattice Energy Application
Born Haber Cycle
Dipole Moment
Lewis Dot Structure
Octet Rule
Formal Charge
Resonance Structures
Additional Practice
Bond Energy

Solution: In chemical reactions, heat is converted into chemical energy (the potential energy stored in chemical bonds) or vice versa. Thus, enthalpy change for a reaction can be approximated from: /ΔH/circ =

Problem

In chemical reactions, heat is converted into chemical energy (the potential energy stored in chemical bonds) or vice versa. Thus, enthalpy change for a reaction can be approximated from:

/ΔH/circ = D/rm(reactants) - D/rm(products)

where "D" represents bond dissociation energies of the reactants and products, respectively. The table below contains the bond dissociation energies for common bonds. The information can be used to calculate the energy needed to break all the bonds in a given molecule.

C-C 350

C=C 611

C-H 410

C-O 350

C-O 732

O-O 180

O=O 498

H-O 4

a) Calculate the bond dissociation energy for the breaking of all the bonds in a mole of methane, CH4.

b) What is the bond dissociation energy for breaking all the bonds in a mole of O 2 molecules?

c) Calculate the bond dissociation energy needed to break all the bonds in a mole of carbon dioxide,CO2.