Q: 3. What is the difference between a balanced and an unbalanced chemical equation?

The difference is: a) A balanced equation has equal numbers of atoms for each element on both sides. b) An unbalanced equation does not follow the Law of Conservation of Mass.

Q: 6. What is an example of a redox reaction?

CuO + H₂ → Cu + H₂O Here, CuO is reduced and H₂ is oxidized.

Q: 9. What is the difference between exothermic and endothermic reactions?

Exothermic : Releases heat (e.g., burning of coal) Endothermic : Absorbs heat (e.g., photosynthesis)

Question 1

1. What is a chemical reaction?

Accepted Answer

A chemical reaction is a process where one or more substances (reactants) change to form new substances (products) with different properties.

Question 2

2. What are the main characteristics of a chemical reaction?

Accepted Answer

Change in color
Change in state
Evolution of gas
Change in temperature
Formation of precipitate

Question 3

3. What is the difference between a balanced and an unbalanced chemical equation?

Accepted Answer

The difference is:
a) A balanced equation has equal numbers of atoms for each element on both sides.
b) An unbalanced equation does not follow the Law of Conservation of Mass.

Question 4

4. Why should chemical equations be balanced?

Accepted Answer

Because the Law of Conservation of Mass states that matter can neither be created nor destroyed in a chemical reaction. So, atoms must be balanced on both sides.

Question 5

5. What are the types of chemical reactions?

Accepted Answer

Combination Reaction
Decomposition Reaction
Displacement Reaction
Double Displacement Reaction
Redox Reaction

Question 6

6. What is an example of a redox reaction?

Accepted Answer

CuO + H₂ → Cu + H₂O
Here, CuO is reduced and H₂ is oxidized.

Question 7

7. What is corrosion?

Accepted Answer

Corrosion is the slow destruction of metals when exposed to air and moisture (e.g., rusting of iron).

Question 8

8. What is rancidity, and how can it be prevented?

Accepted Answer

Rancidity is the oxidation of oils/fats in food, leading to a bad taste and smell. It can be prevented by refrigeration, vacuum packing, and using antioxidants.

Question 9

9. What is the difference between exothermic and endothermic reactions?

Accepted Answer

Exothermic: Releases heat (e.g., burning of coal)
Endothermic: Absorbs heat (e.g., photosynthesis)

Question 10

10. What are decomposition reactions and their types?

Accepted Answer

Decomposition reactions involve breaking a compound into simpler substances. Types include: - Thermal
Photolytic
Electrolytic

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