Chemical reactions and their types

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Textbook

Karnataka state textbook Science for class 8: Chapter 11-Chemical reactions and their types

Additional information

Useful websites

Redox reaction
Oxidation and Redox reaction

Physical and Chemical changes- A review worksheet on physical and chemical changes

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Concept #

Learning objectives

Notes for teachers

These are short notes that the teacher wants to share about the concept, any locally relevant information, specific instructions on what kind of methodology used and common misconceptions/mistakes.

Activity No 1

  • Estimated Time
    • 10 minutes
  • Materials/ Resources needed
    • Sodium chloride-NaCl
      Distilled water-
      Test tube
      Test tube holder
      Spirit laamp
  • Prerequisites/Instructions, if any
    • do not forget to use heat resistant gloves before starting the demonstration
  • Multimedia resources
  • Website interactives/ links/ simulations
  • Process (How to do the activity)
    • Take clean dry test tube and add 5g of NaCl then add about 5ml of water to it to prepare sodium cloride solution.Heat the solution using spirit lamp to evaporate the water to get the sodium chloride in solid state.
      You may collect the vapours of water in a test tube and condense it to get water in liquid state.
  • Developmental Questions (What discussion questions)
  1. what is the state of Sodium chloride taken in the test tube?
  2. What is the state of water added to the test tube?
  3. What is the state of Sodium chloride just after the addition of water?
  4. what happens to the Sodium chloride in the test tube when the test tube is thoroughly Shaken?
  5. what changes do you observe when the Sodium chloride solution in the test tube is boiled ?
  • Evaluation (Questions for assessment of the child)
    • What is the speciality of a Physical change?
  • Question Corner

Activity No 2

  • Estimated Time:15-20 minutes
  • Materials/ Resources needed:Copper sulphate solution, Iron nails,Spatula, Glass rod, Cotton thread etc.
  • Prerequisites/Instructions, if any:
  1. Please Wear apron in laboratory.
  2. Please use Forceps in handling Iron nails.
  3. Please use glass rod to stir the solution.
  • Multimedia resources
  • Website interactives/ links/ simulations
  • Process (How to do the activity):

1. Take one beaker (usually 100-150ml is sufficient), rinse it properly.
2. Take 100ml of Copper sulphate solution in the beaker.

Preparation of Copper sulphate Solution: Mix the Copper sulphate powder in water  in the ratio of 1:10 to prepare the Copper sulphate solution.

3. Take an fresh Iron Nail and tie it with a thread(u can use forcep instead of thread for easy handling). Leave it into the Copper sulphate solution.
4. Keep this for about 15-20 minutes.
5. After 20 minutes we see the deposition of Copper over iron nail.

The process of losing electrons is called "Oxidation" and the process of gaining electrons is called "Reduction". These two processes taking place simultaneously hence we call it as “Redox reaction”. Here, Iron loses electrons whereas Copper gains electrons. So, Iron is more reactive than Copper hence, it displaces Copper from Copper sulphate solution.

                     CuSO4 + Fe → FeSO4 + Cu 
  • Developmental Questions (What discussion questions)

1. What is the colour of Copper sulphate crystal?
2. Is Copper sulphate crystals dissolve in water ?

  • Evaluation (Questions for assessment of the child)

What is the use of Redox reaction in daily life?

Concept #

Learning objectives

Notes for teachers

These are short notes that the teacher wants to share about the concept, any locally relevant information, specific instructions on what kind of methodology used and common misconceptions/mistakes.

Activity No 3 salts and solubility

Activity No 4 PhET Activity Concentration of salts

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