5.1.1

Energy Conservation

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Energy Transfer/Conservation

In chemical reactions, energy is not created or destroyed. Energy is conserved (saved) and transferred between objects. Chemical reactions are exothermic or endothermic, depending on the energy transfers that happen:

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

Exothermic reactions

  • Energy from the reacting chemicals is transferred to the surroundings, which often increase in temperature as a result. Examples include:
    • Combustion.
    • Neutralisation.
    • Oxidation.
Illustrative background for Endothermic reactionsIllustrative background for Endothermic reactions ?? "content

Endothermic reactions

  • Energy from the surroundings is transferred to the reacting chemicals, causing the temperature of the surroundings to decrease. Examples include:
    • Thermal decomposition.
    • The reaction that happens when citric acid is combined with sodium hydrogen carbonate (sodium bicarbonate).

Jump to other topics

1Atomic Structure

2Chemical Bonding

3Quantitative Chemistry

4Chemical Changes

5Energy Changes

6The Rate & Extent of Chemical Change

7Organic Chemistry

8Chemical Analysis

9Chemistry of the Atmosphere

10Using Resources

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