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प्रश्न
Given reason:
Burning of paper is a chemical change.
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उत्तर
When a piece of paper is burnt a new substance ash is produced. Even when the burning is stopped, the ash cannot be changed back into paper. This shows that the formation of the ash from paper is a permanent and irreversible change.
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संबंधित प्रश्न
Classify the following as chemical or physical change:
Passing of electric current through water, and water breaking down into hydrogen and oxygen gases.
State the differences between a physical change and a chemical change.
State four differences between physical and chemical changes.
Which of the following are chemical changes ?
- decaying of wood
- burning of wood
- sawing of wood
- hammering of nail into wood
Give reasons why – separation of mixtures e.g. iron from a mixture of iron and sulphur is a physical change, but heating a mixture of iron and sulphur is considered a chemical change.
State whether the following statement is true or false. If false write the correct statement.
Melting of butter and wax are examples of chemical changes.
Name the following:
The type of change physical or chemical involved – ‘when a substance undergoes a change in state, colour or size’.
Gas exists in three states as solid, liquid, and gas.
Water is the universal solvent. Why?
What kind of change is shown by tearing of paper?
