Question

Define the following chemical reaction? Write 2 chemical equation from each .
a)Combination reaction .
b)Decomposition reaction .
c)Displacement reaction .
d)Double displacement reaction .
e)Oxydation and reduction (Redox) reaction.

Answer 1

Dear Student,

Chemical reactions are processes in which substances change into other substances.
1. Combination Reactions

• Elements are joined together.
  
• element + element → compound
  
• 2H₂ + O₂ → 2H₂O
  
• Compounds are joined together
  
• compound + compound → compound
  
• 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

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2. Decomposition Reactions

• A compound breaks into parts.
  
• compound → element + element
  
• 2H₂O → 2H₂ + O₂

Some decomposition complications with heat:

• Some acids, when heated, decompose into an acidic oxide and H₂O. H₂SO₃ → SO₂ + H₂O
• Metallic hydroxides, when heated, decompose into a metallic oxide and H₂O. Ca(OH)₂ → CaO + H₂O
• Metallic carbonates, when heated, decompose into a metallic oxide and CO₂. Li₂CO₃ → Li₂O + CO₂
• Metallic chlorates, when heated, decompose into metallic chlorides and O₂. 2KClO₃ → 2KCl + 3O₂

3. Single Displacement Reactions

• A single element replaces an element in a compound.
  
• element + compound → element + compound
  
• Zn + 2HCl → H₂ + ZnCl₂

4. Double Displacement Reactions

• An element from each of two compounds switch places.
  
• compound + compound → compound + compound
  
• H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O

5. Oxidation-Reduction Reactions

• Any reaction in which elements experience a change in oxidation number.
  
• one atom gains e^&minus and another atom looses e^&minus
  S + O₂ → SO₂
• In the reaction above, sulfur and oxygen both have an oxidation number of zero before the reaction. After the reaction, sulfur is +4 and oxygen is −2.

Regards