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प्रश्न
Give four difference between physical and chemical changes.
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उत्तर
The differences are Physical and Chemical Changes:
Physical change
- In a physical change no new substance is formed and the chemical composition of substance remains same. There are changes only in physical properties and state.
- Temporaiy change which can be reversed by simple physical methods.
- Weight of original substance doesn’t change
- Energy like heat, light etc. may or may not be absorbed or released
Chemical change
- In a chemical change new substance with entirely different chemical composition and properties is formed.
- Permanent change and irreversible
- Weight of original substances may increase or decrease
- Energy like heat, light etc. are given out or absorbed.
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संबंधित प्रश्न
When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both the chemical and physical changes take place.
Tick the most appropriate answer.
3. Physical changes are
- permanent.
- periodic,
- temporary
- irreversible.
What are reversible and irreversible changes ? Give one example for each.
State whether the following is physical or chemical change.
Digestion of food —
True or false
Dissolving of a solid in liquid is a physical change.
Classify the following as a physical or a chemical change.
Boiling of water
Distinguish between the following.
Physical change and chemical change
Name the following:
The type of change physical or chemical involved – ‘when a substance undergoes a change in state, colour or size’.
State which of the following pertain to – chemical changes.
- Substance retains its identity.
- The change is permanent.
- No new substance is formed.
- Is easily reversible.
- Produces one or more new substances by a change in its composition.
- The change is temporary.
- The composition and properties of the original substance are not altered.
Keeping a stone in sunlight for few hours is ______.
