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प्रश्न
Is a change of state of matter – a physical or a chemical change. Give reasons.
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उत्तर
- There are three different states of matter: solid, liquid, and gas. The transition between various states, such as solid to liquid (melting), liquid to gas (boiling), and vice versa (freezing and condensation), is referred to as a change of state.
- Take water (H2O) as an example. There are three states of water: As a solid (ice), a liquid (water), or a gas (steam).
- Water becomes ice (solid) when it freezes. Ice melts and returns to liquid form as water. Water transforms into steam (gas) when it boils. Steam condenses back into liquid water when it cools.
- The chemistry of water (H2O) remains unchanged during these modifications. The actual chemical identity of water remains unchanged; the molecules are merely rearranged.
- We categorize the change of state of matter as a physical change as the substance's chemical makeup does not alter throughout the transition. Even though a substance undergoes a physical change, its chemical identity is unaffected.
- The change of state of matter is a physical change because the chemical composition does not alter; it remains H2O in all states.
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संबंधित प्रश्न
Classify the changes involved in the following process as physical or chemical changes:
Photosynthesis
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.
Change is the law of nature and occurs in our everyday life, at all times and in all places.
Differentiate between the following change with a suitable example.
Periodic and non-periodic change
Potassium chloride is added to water and stirred. A salt solution is obtained, which is then boiled, leaving behind a residue.
- Is the above change physical or chemical?
- Name the residue which remains behind after the salt solution is boiled.
- Is the change reversible or not reversible?
- Are the composition and properties of the original substance altered?
- Give a reason why the above experimentation would not be possible if calcium carbonate was taken in place of potassium chloride.
Select the chemical changes from the following list of changes
Drying of a fruit
Select the chemical changes from the following list of changes
Change of seasons
Select the correct answer from the choice given below to complete the sentence
The matter is added or removed during a ____________ change.
Filling up a balloon with hot air is a _______ change.
Mention a few physical properties of a substance.
