Question

6. Bursting of firecrackers
4. Burning of wood
5. Dissolving salt in water
7. Burning of coal Co 8. Glowing of an electric lamp Pc 9. Rusting of iron
F. Answer the following in detail.
1. Differentiate between the following changes with suitable examples.
a. Desirable and undesirable changes
2. Define a physical change and a chemical change. Give two examples of each.
3. Give two differences between a physical change and a chemical change.
b. Reversible and irreversible changes
4. Explain why the burning of a candle is an example of both physical as well as chemical changes
Think and answer
1. The processes of boiling and evaporation are physical changes. Why?
2. Sublimation of ammonium chloride is a physical change. Why?
3. When finely powdered iron and sulphur are heated together, a chemical change occurs. Why
Projects & Activities
Activity: Write an invisible message
Cut a lemon and squeeze it to get some lemon juice. Use this juice as your 'ink'.
Write a short message for your friend on a piece of paper with the help of a​

Answer 1

Answer:

i can't understand your language please try to write in hindi or English