5.1.4

Energy Change of a Reaction

Test yourself

Chemical Bonds

All chemical bonds have a 'bond energy' that measures the strength of chemical bonds. By subtracting the total bond energies of the products from the total bond energies of reactants, we can see if a reaction is endothermic or exothermic (energy change in kJ mol-1).

Illustrative background for Exothermic reactionsIllustrative background for Exothermic reactions ?? "content

Exothermic reactions

  • Energy released by forming bonds > energy required to break bonds.
  • I.e. overall energy change of reaction < 0.
Illustrative background for Endothermic reactionsIllustrative background for Endothermic reactions ?? "content

Endothermic reactions

  • Energy released by forming bonds < energy required to break bonds.
  • I.e. overall energy change of reaction > 0.

Jump to other topics

1States of Matter

2Atoms, Elements & Compounds

3Stoichometry

4Electrochemistry

5Chemical Energetics

6Chemical Reactions

7Acids, Bases & Salts

8The Periodic Table

9Metals

10Chemistry of the Environment

11Organic Chemistry

11.1Formulae, Functional Groups & Terminology

11.2Naming Organic Compounds

11.3Fuels

11.4Alkanes

11.5Alkenes

11.6Alcohols

11.7Carboxylic Acids

11.8Polymers

12Experimental Techniques & Chemical Analysis

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