2.2.2

Common Reactions

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Common Types of Reaction

There are some types of reaction which have similar patterns in terms of their atom rearrangement and products. Here, we look at thermal decomposition, oxidation, combustion and displacement reactions.

Illustrative background for Thermal decomposition reactionsIllustrative background for Thermal decomposition reactions ?? "content

Thermal decomposition reactions

  • Thermal decomposition is when one reactant breaks down into a few different products.
  • There is always one reactant and more than one product.
    • You have to heat the reactants to get them to decompose.
  • E.g. Calcium carbonate → calcium oxide + carbon dioxide
    • CaCO3 → CaO + CO2
  • E.g. Copper carbonate → copper oxide + carbon dioxide
    • CuCO3 → CuO + CO2
Illustrative background for Oxidation reactionsIllustrative background for Oxidation reactions ?? "content

Oxidation reactions

  • Oxidation is when something reacts with oxygen to make a product that contains oxygen.
  • One of the reactants is always oxygen and the name of the product usually ends in ‘oxide’.
  • Metals can be oxidised.
  • E.g. Magnesium + oxygen → magnesium oxide.
    • 2Mg + O2 → 2MgO
  • Iron + oxygen → iron oxide
    • 4Fe + 3O2 → 2Fe2O3
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Combustion

  • Combustion is the scientific word for ‘burning’.
  • A fuel reacts with oxygen to make carbon dioxide and water as products.
  • There are many different fuels, but the products are always carbon dioxide and water.
    • Light and heat energy are also produced.
  • E.g. Word equation: methane + oxygen → water + carbon dioxide
    • Symbol equation: CH4 + 2O2 → 2H2O + CO2
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Incomplete combustion

  • The previous reactions are all called ‘complete combustion’, which happens when there is enough oxygen around.
  • If there isn’t enough oxygen around, then ‘incomplete combustion’ happens instead.
    • This makes carbon monoxide rather than carbon dioxide.
  • E.g.
    • Word equation: methane + oxygen → water + carbon monoxide
    • Symbol equation: 2CH4 +3 O2 → 4H2O + 2CO
Illustrative background for Displacement reactionsIllustrative background for Displacement reactions ?? "content

Displacement reactions

  • A displacement reaction is when the different parts of compounds swap due to changes in reactivity.
  • The most reactive element can ‘push out’ another and form a new compound.
  • You can find the reactivity of metals in the reactivity series which lists the most reactive element at the top to the least reactive element at the bottom.
  • E.g:
    • Al + CuCl3 → AlCl3 + Cu

Jump to other topics

1Biology

1.1Cells, Tissues & Organs

1.2Reproduction & Variation

1.3Ecological Relationships & Classification

1.4Digestion & Nutrition

1.5Plants & Photosynthesis

1.6Biological Systems & Processes

2Chemistry

2.1Particles

2.2Chemical Reactions

2.3Atoms, Elements, Compounds

2.4The Periodic Table

2.5Materials & the Earth

2.6Reactivity

2.7Energetics

2.8Properties of Materials

3Physics

3.1Energy

3.2Forces & Motion

3.3Waves

3.4Electricity & Magnetism

3.5Matter

3.6Space Physics

4Thinking Scientifically

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