Class 8 Science Chapter 7 Particulate Nature of Matter Solutions | Curiosity NCERT Answers

  


 

๐ŸŒŸ Class 8 Science – Curiosity Chapter 7

๐Ÿ”ฌ Particulate Nature of Matter (เคชเคฆाเคฐ्เคฅ เค•ा เค•เคฃीเคฏ เคธ्เคตเคฐूเคช)


๐ŸŸข 1. Choose the correct option.

The primary difference between solids and liquids is that the constituent particles are:

(i) closely packed in solids, while they are stationary in liquids.
(ii) far apart in solids and have fixed position in liquids.
(iii) always moving in solids and have fixed position in liquids.
(iv) closely packed in solids and move past each other in liquids.


Answer:

๐Ÿ‘‰ Correct option is (iv) closely packed in solids and move past each other in liquids.

๐Ÿง  Explanation:

  • ๐Ÿงฑ Solids (เค ोเคธ) particles tightly packed + fixed position
  • ๐Ÿ’ง Liquids (เคฆ्เคฐเคต) particles close but can slide (เคซिเคธเคฒเคจा) past each other

๐ŸŽ“ Example:

  • ๐Ÿ‘จ‍๐ŸŽ“ Solid = students sitting on fixed benches
  • ๐Ÿƒ Liquid = students moving freely during break

๐ŸŸข 2. Which of the following statements are true? Correct the false statements.

(i) Melting ice into water is an example of the transformation of a solid into a liquid.
(ii) Melting process involves a decrease in interparticle attractions during the transformation.
(iii) Solids have a fixed shape and a fixed volume.
(iv) The interparticle interactions in solids are very strong, and the interparticle spaces are very small.
(v) When we heat camphor in one corner of a room, the fragrance reaches all corners of the room.
(vi) On heating, we are adding energy to the camphor and the energy is released as a smell.


Answers:

✔️ (i) True
๐Ÿ‘‰ Melting = solid liquid (เค ोเคธ เคธे เคฆ्เคฐเคต เคฎें เคชเคฐिเคตเคฐ्เคคเคจ)

✔️ (ii) True
๐Ÿ‘‰ Heat energy weakens interparticle forces (เค•เคฃों เค•े เคฌीเคš เค†เค•เคฐ्เคทเคฃ เคฌเคฒ)

✔️ (iii) True
๐Ÿ‘‰ Solids have:

  • ๐Ÿ“ Fixed shape
  • ๐Ÿ“ฆ Fixed volume

✔️ (iv) True
๐Ÿ‘‰ Strong forces + small spaces = rigid structure ๐Ÿ’ช

✔️ (v) True
๐Ÿ‘‰ Camphor turns into gas spreads everywhere ๐ŸŒฌ️

(vi) False

✏️ Correct Statement:
๐Ÿ‘‰ Heating camphor gives energy it changes into gas
๐Ÿ‘‰ Gas particles spread in air reach our nose ๐Ÿ‘ƒ we smell it

⚠️ Energy is not released as smell, it helps in change of state.


๐ŸŸข 3. Choose the correct answer with justification.

If we could remove all the constituent particles from a chair, what would happen?

(i) Nothing will change.
(ii) The chair will weigh less due to lost particles.
(iii) Nothing of the chair will remain.


Answer:

๐Ÿ‘‰ Correct option is (iii) Nothing of the chair will remain.

๐Ÿง  Explanation:

  • Chair = made of particles ๐Ÿงฑ
  • If particles are removed chair itself disappears

๐Ÿ’ก Matter is not a container of particles, it is particles itself.


๐ŸŸข 4. Why do gases mix easily, while solids do not?


Answer:

๐ŸŒฌ️ Gases (เค—ैเคธें):

  • Particles far apart
  • Very weak forces
  • High speed movement ๐Ÿš€
    ๐Ÿ‘‰ Easily mix with each other

๐Ÿงฑ Solids (เค ोเคธ):

  • Particles tightly packed
  • Strong forces ๐Ÿ’ช
  • Fixed positions
    ๐Ÿ‘‰ Cannot move cannot mix

๐Ÿ“Œ Conclusion:
๐Ÿ‘‰ Freedom of movement = mixing ability


๐ŸŸข 5. When spilled on the table, milk in a glass tumbler flows and spreads out, but the glass tumbler stays in the same shape. Justify this statement.


Answer:

๐Ÿฅ› Milk (Liquid):

  • Particles close but can move (เค—เคคिเคถीเคฒ)
  • Weak forces
    ๐Ÿ‘‰ Flows and spreads easily

๐Ÿฅค Glass Tumbler (Solid):

  • Particles tightly packed
  • Strong forces ๐Ÿ’ช
    ๐Ÿ‘‰ Fixed shape does not flow

๐Ÿ“Œ Conclusion:
๐Ÿ‘‰ Liquids flow, solids maintain shape


 

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