March 2, 2014

10th Class Chemistry New Syllabus - Chemical Reactions Activities

Activity-1: Take about 1 gm of quick lime (calcium oxide) in a beaker. Add 10 ml of water to this. Touch the beaker with your finger.

1) What do you notice?
Test the nature of solution with litmus paper.

2) What is the nature of the solution?
In the above activity you will notice that, the beaker is hot when you touch it with you finger. The reason is that the calcium oxide (quick lime) reacts with water and releases heat energy. White calcium oxide dissolves in water producing colourless solution. The solution obtained Is a basic solution. This you will find with litmus paper test.

Activity - 2:

Take about 100 ml of water in a beaker and dissolve a small quantity of Sodium sulphate (Na2SO4). Takeabout 100ml of water in another beaker and dissolve a small quantity of Barium chloride (BaCl2), observe the colours of the solutions obtained.
- What is the colour of these solutions?
- Can you name the solutions obtained?
Add the solution that obtained into beaker and observe changes.
- Did you observe any change on mixing these solutions?

Activity - 3:

Take a few zinc granules in a conical flask. Add about 5 ml of dilute hydrochloric acid to the conical flask. Observe the changes in the conical flask.
- What changes did you notice?
Now keep a burning match stick near the mouth of the conical flask.
- What happens to burning match stick?
- Touch the test tube with your fingers. What did you notice?
- Is there any change in temperature?

From the above activities you can conclude that:

1. A change that changes state and colour of substance.
2. A change that release heat energy.
3. A change which forms an insoluble substance as precipitate.
4. A change that liberate a gas.

In our daily life we observe variety of changes taking place around us. In this chapter we study various types of chemical reactions and their symbolic representation.

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