CHEMICAL REACTIONS AND EQUATIONS

1. ACTIVITY 1.1

1.1. Clean a magnesium ribbon about 3-4 cm long by rubbing it with sandpaper.

1.2. Hold it with a pair of tongs. Burn it using a spirit lamp or burner and collect Ash so formed in watch glass

1.2.1. The magnesium ribbon burns with a dazzling white flame and changes into powder. This powder is magnesium oxide.

1.3. Observation- The physical state has changed.

1.4. Equation- 2Mg + O2 = 2MgO

2. Characteristics of Chemical Reaction

2.1. Change in state

2.2. Change in colour

2.3. Evolution of gas

2.4. Change in temperature

3. Unbalanced Equation (Skeletal Equation)

4. It is a process in which substances called reactants get converted into one or more different substances called products.

4.1. The new substance formed during the reaction is known as product.

4.2. The substance that undergoes chemical change in the reaction are known as reactants.

4.3. Whenever a chemical change occurs, a chemical reaction has taken place.

5. ACTIVITY 1.2

5.1. Take lead nitrate solution in a test tube.

5.2. Add potassium iodide solution to this.

5.3. Observation- colour change. A yellow precipitate is formed.

5.4. Equation- PbNO3 + KI = KNO3 + PbI

6. ACTIVITY 1.3

6.1. Take few zinc granules in a conical flask or a test tube. Add dilute HCl or NaCl to this .

6.2. Observation- Evolution of gas and the temperature changes. The test tube becomes hot.

6.3. Equation- Zn + 2HCl = ZnCl + H2