DSERT - 8 - Science :: Chemical Reactions and their types

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Go To: DSERT-Science-Grade 8

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[AUTHOR: GAYATHRI ARUN]


Dear Volunteer,


Please find below the detailed lesson plan and PPT for this chapter in the language mentioned against the respective link. While the lesson plan will give an overall flow of the lesson, the PPT will include lesson flow as well as the presentations for the class.


https://drive.google.com/open?id=1rC4ZVssuwQ8HrpEhsXToPHRNl4ziiYzf (Lesson Plan - English)


https://drive.google.com/open?id=1ah8Y59U6tUsGAkMNLe97fk5vsiuBBkYw(PPT - English)


You may use the content as it is or download and modify them to suit the students requirements.


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The worksheets of the lesson can be accessed from the worksheet tab.


Kindly rate the lesson plan and share your suggestions and comments on the lesson plan in the comments box below. Your valuble suggestions and comments will help us to improve the content.


[AUTHOR: GAYATHRI ARUN]


ACTIVITY 1

Take some ice cubes in a beaker and expose it to sunlight for some time. Do the reverse and notice the changes.


ACTIVITY 2

Place some bright iron nails ina test tube half filled with water and examine after two or three days. The nails are covered with a reddish brown mass known as rust which has properties different from iron.

ACTIVITY 3

Classify the following into chemical and physical changes

1. Rusting of Iron

2. Ripening of fruit


ACTIVITY 1

Immerse an iron nail in copper sulphate solution for some time. You will observe the deposit of copper on iron nail. CuSO4 + Fe → FeSO4 + Cu

ACTIVITY 2

Take clear bleaching powder solution (which is a source of chlorine gas) in a test tube. Add potassium iodide solution. The solution turns pink due to the formation of iodine. 

Cl2 

+   2KI     →   2KCl  +   I2 ( ) Chlorine + ( ) Potassium  iodide  → ( ) Potassium chloride + ( ) Iodine In the above two examples a more reactive metal or non metal displaces a less reactive metal or non metal respectively from their compounds. These are examples for displacement reactions’. Can you arrange copper, iron and silver in the increasing order of the reactivity?

ACTIVITY 3

Observe the following reaction: Zn + H2SO4 → ZnSO4 + H2 (dilute) Identify the displaced element and displacing agent in the above reaction. In chemical displacement more reactive element displaces the less reactive element from their compounds.

ACTIVITY 4

Add sodium carbonate solution to magnesium sulphate solution in a test tube. We see a white precipitate of magnesium carbonate. MgSO4 + Na2CO3 → MgCO3 + Na2SO4

ACTIVITY 5


Add sodium carbonate solution to calcium chloride solution taken in a test tube.

We see a white precipitate of calcium corbonate 

CaCl2 + Na2CO3 → CaCO3    + 2NaCl In the above two examples there is a mutual exchange of metallic and the non metallic parts. Such reactions are called double displacement or double decomposition reactions.

ACTIVITY 6

In the following example can you write the parts or radicals which are exchanged? MgCl2 + Na2CO3 → MgCO3 + 2 NaCl

ACTIVITY 7

Add Hydrochloric acid solution to Sodium Hydroxide solution (base) taken in a test tube. We come across the following double decomposition reaction. NaOH + HCl → NaCl + H2O

Acids and bases are identified by their action on litmus. Acid turn moist blue litmus to red while bases turn moist red litmus blue. Since the products formed as a result of the reaction between acids and bases are neutral to litmus, the reaction is called neutralization.


ACTIVITY 1

Immerse an iron nail in copper sulphate solution for some time. You will observe the deposit of copper on iron nail. CuSO4 + Fe → FeSO4 + Cu

ACTIVITY 2

Take clear bleaching powder solution (which is a source of chlorine gas) in a test tube. Add potassium iodide solution. The solution turns pink due to the formation of iodine. 

Cl2 

+   2KI     →   2KCl  +   I2 ( ) Chlorine + ( ) Potassium  iodide  → ( ) Potassium chloride + ( ) Iodine In the above two examples a more reactive metal or non metal displaces a less reactive metal or non metal respectively from their compounds. These are examples for displacement reactions’. Can you arrange copper, iron and silver in the increasing order of the reactivity?

ACTIVITY 3

Observe the following reaction: Zn + H2SO4 → ZnSO4 + H2 (dilute) Identify the displaced element and displacing agent in the above reaction. In chemical displacement more reactive element displaces the less reactive element from their compounds.

ACTIVITY 4

Add sodium carbonate solution to magnesium sulphate solution in a test tube. We see a white precipitate of magnesium carbonate. MgSO4 + Na2CO3 → MgCO3 + Na2SO4

ACTIVITY 5


Add sodium carbonate solution to calcium chloride solution taken in a test tube.

We see a white precipitate of calcium corbonate 

CaCl2 + Na2CO3 → CaCO3    + 2NaCl In the above two examples there is a mutual exchange of metallic and the non metallic parts. Such reactions are called double displacement or double decomposition reactions.

ACTIVITY 6

In the following example can you write the parts or radicals which are exchanged? MgCl2 + Na2CO3 → MgCO3 + 2 NaCl

ACTIVITY 7

Add Hydrochloric acid solution to Sodium Hydroxide solution (base) taken in a test tube. We come across the following double decomposition reaction. NaOH + HCl → NaCl + H2O

Acids and bases are identified by their action on litmus. Acid turn moist blue litmus to red while bases turn moist red litmus blue. Since the products formed as a result of the reaction between acids and bases are neutral to litmus, the reaction is called neutralization.




























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