Question

Choose the correct option and fill in the blanks

In a______________[physical change /chemical change], a new substance is formed.

Answer 1

Chemical Changes: A change that alters the specific properties of a material by bringing about a change in its molecular composition, followed by a change in state, is called a chemical change.

• A chemical change results in the formation of one or more new products.
• The weight of the substance undergoing chemical change usually changes.
• The chemical change is permanent and irreversible.
• During a chemical change, energy is either absorbed or given out.
• For example, wood burns to form ash. Ash is a new product.

Other examples:

1. Burning of charcoal
2. Burning of candle
3. Digestion of food
4. Curdling of milk
5. Formation of biogas (Gobar gas)
6. Burning of petrol or diesel
7. Drying of paint
8. Rusting of iron
9. Ripening of fruit
10. Clotting of blood
11. Fading of the color of a dyed cloth
12. Baking of cake
13. Photosynthesis
14. Butter turning rancid
15. Electrolysis of water into hydrogen and oxygen
16. Formation of water from hydrogen and oxygen

Hence, In a chemical change, a new substance is formed.