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प्रश्न
Explain why burning of wood and cutting it into small piece are considered as two different types of changes.
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उत्तर
- Wood cannot be joined again to form the original piece, but its properties do not change.
- This is a physical change. Wood cannot be restored to its original form after burning.
- Its properties also change, and heat is produced. This is a chemical change. Here, there are two different states of burning the wood and cutting it into small pieces.
- In this situation, two different types of changes are considered.
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संबंधित प्रश्न
Classify the following as chemical or physical change:
Burning of paper and wood
Explain the following giving an example.
Pure substance
Classify the following changes as physical or chemical: curdling of milk
State the differences between a physical change and a chemical change.
Solve this crossword by using the clues that follow.
Across
1. Energy in the form of sunlight is absorbed by the green plants in this process.
4. The reddish-brown substance formed over iron in the presence of oxygen and moisture.
5. This change is permanent and irreversible.
6. The process in which a solid directly changes into gaseous state.
Down
1. It is the change that takes place in case of swinging pendulum of a clock.
2. Occurrence of this is a non-periodic change as well as a natural change.
3. It is a physical change
What are reversible and irreversible changes ? Give one example for each.
Fill in the blank
Chemical change occurs as a result of __________ between two substances.
True or false
Change of seasons is a non-periodic change.
Name the following:
The final product of the physical change involved during the ‘melting of a piece of wax’.
Digestion of food is a physical change.
