Most Important Textual Questions of Matter in Our Surroundings

Introduction

Understanding matter and its properties is crucial for comprehending the physical world around us. This guide will help you grasp the basic concepts related to the physical nature of matter, its states, and the changes it undergoes.

1. Which of the Following Are Matter?

Chair, air, almonds, lemon water, smell of perfume

• Explanation: Matter is anything that occupies space and has mass. Chair, air, almonds, lemon water, and the smell of perfume all fit this definition. Love, smell, hate, thought, and cold are not matter.

2. Why Does the Smell of Hot Sizzling Food Reach You Several Meters Away, But You Need to Go Close to Smell Cold Food?

Reason: The smell of hot sizzling food spreads faster because heat increases the kinetic energy of the particles, causing them to move rapidly and mix with the air, spreading the smell over a greater distance.

3. A Diver is Able to Cut Through Water in a Swimming Pool. Which Property of Matter Does This Observation Show?

Property: This observation shows that particles of matter have spaces between them, allowing the diver to move through water.

4. What Are the Characteristics of the Particles of Matter?

Characteristics:

• Particles of matter have space between them.
• Particles of matter are in constant motion.
• Particles of matter attract each other.

5. What About a Rubber Band, Can It Change Its Shape on Stretching? Is It a Solid?

Answer: Yes, a rubber band can change its shape on stretching, but it is still considered a solid because it regains its shape when the force is removed.

6. What About Sugar and Salt? When Kept in Different Jars, Do They Take the Shape of the Jar? Are They Solid?

Answer: Yes, sugar and salt take the shape of the jar they are kept in, but they are still solids because their individual particles maintain a fixed shape.

7. What About a Sponge? It Is a Solid Yet We Are Able to Compress It. Why?

Answer: A sponge is solid but can be compressed because it has tiny pores filled with air. When compressed, the air is expelled, and the sponge can be squished.

8. Arrange the Following in Order of Increasing Density – Air, Exhaust from Chimneys, Honey, Water, Chalk, Cotton, and Iron.

Order: Air, Exhaust from Chimneys, Cotton, Water, Honey, Chalk, Iron.

9. (a) Tabulate the Differences in the Characteristics of States of Matter.

(b) Comment Upon the Following: Rigidity, Compressibility, Fluidity, Filling a Gas Container, Shape, Kinetic Energy, and Density.

• Rigidity: Solids are rigid.
• Compressibility: Gases are highly compressible, liquids are less compressible, and solids are incompressible.
• Fluidity: Gases and liquids flow, solids do not.
• Filling a Gas Container: Gases fill the entire volume of the container.
• Shape: Solids have a definite shape, liquids take the shape of the container, gases have no definite shape.
• Kinetic Energy: Gases have the highest kinetic energy, followed by liquids, and then solids.
• Density: Solids have high density, liquids have moderate density, and gases have low density.

10. Give Reasons

(a) A Gas Fills Completely the Vessel in Which It Is Kept:
Gases have particles that move freely and spread out to fill the entire space of the container.

(b) A Gas Exerts Pressure on the Walls of the Container:
Gas particles collide with the walls of the container, exerting pressure.

(c) A Wooden Table Should Be Called a Solid:
A wooden table has a definite shape and volume, with particles closely packed in a fixed arrangement.

(d) We Can Easily Move Our Hand in Air but Not Through a Solid Block of Wood:
Air particles are loosely packed and can move freely, while particles in wood are tightly packed, requiring more force to move through.

11. Liquids Generally Have Lower Density Compared to Solids, But Ice Floats on Water. Why?

Reason: Ice has a lower density than water because the arrangement of water molecules in ice creates more space between them compared to liquid water.

12. Convert the Following Temperature to Celsius Scale:

(a) 300 K: ( 300 – 273 = 27 Degree Celsius )
(b) 573 K: ( 573 – 273 = 300 Degree Celsius )

13. What Is the Physical State of Water At:

(a) 250°C: Gas (Steam)
(b) 100°C: Gas (Steam)

14. Why Does the Temperature Remain Constant During the Change of State?

Reason: The temperature remains constant during the change of state because the heat energy is used to break the intermolecular bonds rather than increasing the temperature.

15. Suggest a Method to Liquefy Atmospheric Gases.

Method: Increase the pressure and decrease the temperature of the gas to convert it into a liquid.

16. Why Does a Desert Cooler Cool Better on a Hot Dry Day?

Reason: A desert cooler works on the principle of evaporation. On a hot, dry day, the rate of evaporation is higher, which results in better cooling.

17. How Does the Water Kept in an Earthen Pot (Matka) Become Cool During Summer?

Reason: The earthen pot has tiny pores that allow water to seep out and evaporate. The evaporation process absorbs heat from the water inside, cooling it down.

18. Why Does Our Palm Feel Cold When We Put Some Acetone or Petrol or Perfume on It?

Reason: Acetone, petrol, or perfume evaporates quickly, absorbing heat from our skin, making our palm feel cold.

19. Why Are We Able to Sip Hot Tea or Milk Faster from a Saucer Rather Than a Cup?

Reason: A saucer has a larger surface area than a cup, increasing the rate of evaporation and cooling the tea or milk faster.

20. What Type of Clothes Should We Wear in Summer?

Answer: We should wear light-colored, loose, and cotton clothes in summer as they absorb sweat and facilitate evaporation, keeping us cool.

21. Convert the Following Temperatures to the Celsius Scale:

(a) 293 K: ( 293 – 273 = 20 Degree Celsius )
(b) 470 K: ( 470 – 273 = 197 Degree Celsius )

22. Convert the Following Temperatures to the Kelvin Scale:

(a) 25°C: ( 25 + 273 = 298 K )
(b) 373°C: ( 373 + 273 = 646 K)

23. Give Reasons for the Following Observations:

(a) Naphthalene Balls Disappear with Time Without Leaving Any Solid:
Naphthalene balls undergo sublimation, turning directly into gas without leaving any solid residue.

(b) We Can Get the Smell of Perfume Sitting Several Meters Away:
Perfume particles diffuse rapidly in the air, spreading the smell over a distance.

24. Arrange the Following Substances in Increasing Order of Forces of Attraction Between the Particles: Water, Sugar, Oxygen.

Order: Oxygen, Water, Sugar.

25. What Is the Physical State of Water At:

(a) 25°C: Liquid
(b) 0°C: Solid (Ice)
(c) 100°C: Gas (Steam)

26. Give Two Reasons to Justify:

(a) Water at Room Temperature Is a Liquid:

• It has a definite volume but no definite shape.
• It flows and takes the shape of its container.

(b) An Iron Almirah Is a Solid at Room Temperature:

• It has a definite shape and volume.
• The particles are tightly packed and do not flow.

27. Why Is Ice at 273 K More Effective in Cooling Than Water at the Same Temperature?

Reason: Ice at 273 K absorbs more heat from the surroundings as it melts, providing more effective cooling compared to water at the same temperature.

28. What Produces More Severe Burns, Boiling Water or Steam?

Answer: Steam produces more severe burns than boiling water because it contains more heat energy (latent heat of vaporization).

29. Name A, B, C, D, E, and F in the Following Diagram Showing Change in Its State

Diagram Labels:

• A: Melting
• B: Freezing
• C: Vaporization
• D: Condensation
• E: Sublimation
• F: Deposition

Conclusion

Understanding these fundamental concepts of matter and its properties provides a foundation for exploring the fascinating world of chemistry and the behavior of materials in different conditions. This guide covers the essentials needed to grasp the physical nature of matter, its states, and how it changes under various conditions.