Exothermic Reactions by Sarah Arnold

Sarah Arnold
Mind Map by Sarah Arnold, updated more than 1 year ago
Sarah Arnold
Created by Sarah Arnold about 6 years ago
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A mindmap on exothermic reactions!

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Exothermic Reactions by Sarah Arnold
  1. An exothermic reaction is a chemical reaction that releases energy by light or heat. It is the opposite of an endothermic reaction.. Expressed in a chemical equation: reactants → products + energy
    1. An exothermic reaction occurs when the energy used to break the bonds in the reactants (the starting stuff) is less than the energy released when new bonds are made in the products (the stuff you end up with). This extra energy is given off as heat and there is a temperature rise around the surroundings of the reaction.
      1. Combustion is an example of an exothermic reaction- you can feel the heat given off if you get too close!
    2. In reversible reactions, the reaction in one direction will be exothermic and the reaction in the other direction will be endothermic.
      1. Some examples of exothermic reactions are burning neutralisation, reactions between acids and alkalis and the reaction between water and calcium oxide.
        1. Everything that lets out heat, even from striking a match, and burning fuels are exothermic reactions, no matter how simple it may be.
      2. Obviously, lots of chemical reactions give out energy as heat. Getting heat by burning a fuel is a simple example, but you will probably have come across lots of others in the lab.
        1. Other reactions need a continuous supply of heat to make them work. Splitting calcium carbonate into calcium oxide and carbon dioxide is a simple example of this.
          1. Any chemical reaction will involve breaking some bonds and making new ones. Energy is needed to break bonds, and is given out when the new bonds are formed. It is very unlikely that these two processes will involve exactly the same amount of energy - and so some energy will either be absorbed or released during a reaction.
        2. Because exothermic reactions give out heat, it may result in a change of temperature in the surrounding areas,.
          1. As exothermic reactions release heat energy, the product of the reaction is the heat, with whatever the heat is caused by being the reactant.
          2. It's important to know how much energy fuels release on combustion i.e. their calorific value. Its important to know the energy released on burning petrol. diesel, coal or any other fossil fuel and alternative fuels like hydrogen or biofuels (biomass fuels).
            1. The same sort of data is important in knowing how much energy is released on metabolising foods such as fats and carbohydrates.
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