Question

Prepare a list of the chemical changes that occur in your house and surroundings and discuss these in the class.

Answer 1

Chemical Changes in the House

1. Cooking Food:  When food is cooked, the ingredients undergo chemical changes to form new substances with different tastes and smells. Example: Baking bread, frying eggs, or making rice.

2. Souring of Milk: When milk is left outside, bacteria cause it to turn sour, producing lactic acid.

3. Burning of Wood or Paper: Burning produces ash, smoke, and gases like carbon dioxide, which cannot be reversed.

4. Rusting of Iron: When iron objects like tools or gates are exposed to air and water, they form rust.

5. Digesting Food: The food we eat gets broken down into simpler substances in our stomach due to chemical reactions.

Chemical Changes in the Surroundings

1. Photosynthesis: Plants make their own food by converting carbon dioxide and water into glucose and oxygen with sunlight.

2. Burning of Fuels: Burning petrol, diesel, or wood produces heat, light, and gases like carbon dioxide.

3. Formation of Acid Rain: Harmful gases like sulfur dioxide mix with rainwater to form acids, damaging plants and buildings.

4. Rotting of Fruits: Over time, fruits spoil due to microbial action, releasing a bad smell and turning mushy.

5. Respiration: Animals and humans breathe in oxygen to convert food into energy, producing carbon dioxide and water.