NIOS Class 10 Science and Technology Activity 4.1 Chemical Reactions and Equations

In this activity, we will perform two experiments showing chemical changes during chemical reactions.

 

NIOS Class 10 Science and Technology Project File

This activity is based on the NIOS class 10 science and technology chapter 4, Chemical Reactions and Equations

This activity has two parts:

(1)      Combustion of magnesium

(2)      Reaction between zinc and acid

 

(1)   Combustion of Magnesium (Activity 4.1)

Aim of the activity

To observe the combustion of magnesium and understand the formation of a new substance.

Materials Required

   1. Magnesium ribbon

   2. Sandpaper

   3. A pair of tongs

   4. Spirit lamp or burner

   5. Watch glass

Procedure

We take a 2 cm long magnesium ribbon and clean its surface with a sand paper to remove the layer of magnesium oxide.

 Now we hold the ribbon with a pair of tongs, bring it near the flame of a spirit lamp or burner, and observe the changes.

Observation

We notice that the magnesium ribbon burns with a dazzling white flame, and a white powdery substance is obtained in the watch glass below.

Explanation

Magnesium is a reactive metal, and it burns in the presence of oxygen and undergoes a combustion reaction, forming magnesium oxide, which is a white powdery substance.

2M + O₂ →2MgO

Conclusion

The burning of magnesium ribbon is a combination reaction, and it is an irreversible change. So, it is a chemical change.

(2)   Reaction between Zinc and acid(Activity 4.1)

Aim of the activity

To observe the reaction between a metal and an acid and notice the gas evolution

Materials Required

   1. Zinc granules

   2. Conical flask or test tube

   3. Dilute sulphuric acid or hydrochloric acid

   4. Test tube holder

Procedure

We take a few zinc granules in a conical flask and add a small amount of dilute sulphuric acid or hydrochloric acid.

We observe the changes.

Observation

We observe the release of bubbles around the zinc granules, and the flask becomes hot.

Explanation

Zinc reacts with acid (H₂SO₄ or HCl) and produces salt and hydrogen gas. The gas can be identified as hydrogen because it produces a ‘pop’ sound when a burning candle is brought near soap bubbles filled with gas.

Zn + H₂SO₄ → ZnSO₄ + H₂ ↑

Zn + 2HCl → ZnCl₂ + H₂ ↑

 

The chemical reaction is exothermic because heat is produced.

Conclusion

This activity demonstrates that the reaction of zinc metal with an acid is exothermic and produces hydrogen gas.

So, both reactions demonstrate the formation of a new substance that confirms these are chemical changes.

Frequently Asked Questions

   1.  Why do we clean the magnesium ribbon with sandpaper before burning?

Answer – We clean the magnesium ribbon with sandpaper to remove the layer of MgO on it.

   2. What type of chemical reaction is in part A of the activity?

Answer – Combustion reaction

   3. What is the chemical name of the white powder obtained when the Mg ribbon is burnt?

Answer – Magnesium oxide