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Guilherme Mazui

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What is the Difference Between Endothermic and Exothermic Reactions?

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The main difference between endothermic and exothermic reactions lies in the heat energy that is absorbed or released during the reactions. Here are the key differences:

  • Endothermic Reactions:
  1. Absorb heat energy from the surroundings.
  2. The temperature of the system decreases, as heat is taken up from the surroundings.
  3. The enthalpy of the system increases, indicating that more energy is absorbed when the bonds in the reactants are broken than is released when new bonds are formed.
  4. Examples include photosynthesis and the reaction between ammonium nitrate and water.
  • Exothermic Reactions:
  1. Release heat energy into the surroundings.
  2. The temperature of the system increases, as heat is released to the surroundings.
  3. The enthalpy of the system decreases, indicating that more energy is released when the products are formed than the energy used to break up the reactants.
  4. Examples include the reaction between sodium and chlorine and the formation of water from hydrogen and oxygen.

In summary, endothermic reactions absorb heat energy from the surroundings, resulting in a decrease in temperature, while exothermic reactions release heat energy into the surroundings, leading to an increase in temperature.

On this page
  • What is the Difference Between Endothermic and Exothermic Reactions?
  • Comparative Table: Endothermic vs Exothermic Reactions

    • Comparative Table: Endothermic vs Exothermic Reactions

    Here is a table comparing the differences between endothermic and exothermic reactions:

    Feature Endothermic Reactions Exothermic Reactions
    Energy Absorption or Release Absorbs energy from the surroundings Releases energy into the surroundings
    Temperature Effect Causes a cooling effect by lowering the temperature of the surrounding environment Causes a heating effect by raising the temperature of the surrounding environment
    Enthalpy Change (ΔH) Positive, i.e., ΔH > 0 Negative, i.e., ΔH < 0
    Bond Formation/Breaking Breaking bonds requires energy, and new bonds are formed as a result of heat absorption New bonds are formed, releasing energy in the process
    Examples Photosynthesis, evaporating liquids, melting ice, dry ice, alkane cracking, thermal decomposition, ammonium chloride in water Combustion reactions, respiration, and the formation of many chemical compounds from their elements

    Endothermic reactions absorb energy from the surrounding environment, usually in the form of heat, causing a decrease in the temperature of the system. On the other hand, exothermic reactions release energy into the surroundings, resulting in an increase in temperature.

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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.