er will burn three matchsticks. 2. Observe the matchsticks before and after burning. 3. Read each question carefully and answer it using your prior knowledge and observations. Write your answers in your notebook. Guide Questions 1. What changes happened when the matchsticks were burned? Are these changes physical or chemical? 2. What is a chemical change? 3. Why is burning matchsticks considered a chemical change? 4. Is the change in the burnt matchsticks reversible or irreversible? 5. Why is it important to understand the chemical changes in materials when exposed to high temperatures? 6. Can you think of other examples of chemical changes caused b changes in temperature? Describe the m. Let's Learn​

1. The matchstick turned black, produced smoke, became brittle, and lost its original shape. It cannot be reused or returned to its original state.2. These are chemical changes because the composition of the matchstick changed permanently.3. A chemical change is a process where a substance transforms into a new one with different properties. It usually involves heat, gas, light, or a new substance being formed.4. Burning causes the matchstick’s wood and chemicals to react with oxygen, producing carbon, ash, and gases—new substances. The change is permanent.5. Irreversible, because once the matchstick is burnt, it cannot be returned to how it was.6. Other examples of chemical change caused by heat:Cooking an egg (egg whites solidify permanently)Baking bread (ingredients turn into a new food form)Rusting metal (especially under heat and humidity)

Answered by Sefton | 2025-07-23