AQA GCSE FOUNDATION Chemistry: Metal Reactions with Oxygen

Metal Reactions with Oxygen: Formation and Reduction of Metal Oxides

This tutorial covers the reactions of metals with oxygen, focusing on the formation of metal oxides and their subsequent reduction.

1. Metal + Oxygen ? Metal Oxide

• What happens: When metals react with oxygen, they form metal oxides. This is a chemical reaction where the metal atoms lose electrons and combine with oxygen atoms to form a new compound.

• Examples:

  • Magnesium + Oxygen ? Magnesium Oxide
    2Mg (s) + O2 (g) ? 2MgO (s)

  • Iron + Oxygen ? Iron(III) Oxide 4Fe (s) + 3O2 (g) ? 2Fe2O3 (s)

2. Reactivity Series

• Understanding Reactivity: Metals differ in their reactivity with oxygen. Some react readily, while others require specific conditions.
• The Reactivity Series: A list of metals arranged in order of decreasing reactivity. Metals higher in the series are more reactive.

3. Observations

• Visual Changes: Observe the changes in the metal during the reaction:
  • Magnesium: Burns with a bright white flame, leaving behind a white powdery residue (magnesium oxide).
  • Iron: Rusts slowly in air, forming a reddish-brown oxide.
• Heat: Many metal-oxygen reactions release heat, indicating an exothermic reaction.

4. Reduction of Metal Oxides

• Reversing the Reaction: Metal oxides can be reduced back to their original metal form by removing oxygen.
• Reducing Agent: A substance that removes oxygen from a compound.

• Example:

  • Carbon + Iron(III) Oxide ? Iron + Carbon Dioxide Fe2O3 (s) + 3C (s) ? 2Fe (s) + 3CO2 (g)

5. Key Concepts

• Oxidation: Loss of electrons.
• Reduction: Gain of electrons.
• Redox Reaction: A reaction involving both oxidation and reduction.

6. Applications

• Extraction of Metals: Metals are extracted from their ores using reduction reactions, often with carbon as the reducing agent.
• Corrosion: The process of metal oxides forming on the surface of metals, leading to deterioration.

7. Further Exploration

• Metal oxides and their properties: Explore the different types of metal oxides and their uses.
• Corrosion prevention: Investigate methods to prevent corrosion, such as galvanizing and painting.

This tutorial provides a basic understanding of metal reactions with oxygen and the formation and reduction of metal oxides. Further exploration can delve deeper into the specific properties and applications of these reactions.