Complete Solutions and Summary of Matter in Our Surroundings – NCERT Class 9, Science, Chapter 1 – Summary, Questions, Answers, Extra Questions
Detailed summary and explanation of Chapter 1 “Matter in Our Surroundings” with all question answers, extra questions, and solutions from NCERT Class IX, Science.
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Matter In Our Surroundings
Chapter 1: Science
Complete Study Guide with Interactive Learning
Chapter Overview
What You'll Learn
Physical Nature of Matter
Understanding that matter is made up of particles and their characteristics.
States of Matter
Exploring solid, liquid, and gas states and their properties.
Change of State
Learning how matter changes states with temperature and pressure.
Evaporation
Factors affecting evaporation and its cooling effect.
Historical Context
This chapter introduces the concept of matter based on ancient classifications like Panch Tatva (air, earth, fire, sky, water) by Indian philosophers and similar ideas by Greek philosophers. Modern science classifies matter into solids, liquids, and gases based on physical properties.
Key Highlights
Matter occupies space and has mass. Particles are very small, continuously moving, with spaces between them, and attract each other. States change with temperature (melting, boiling) and pressure. Evaporation causes cooling and depends on surface area, temperature, humidity, and wind speed.
Comprehensive Chapter Summary
1. Introduction to Matter
Everything in the universe is matter, which occupies space and has mass. Ancient Indian and Greek philosophers classified matter into five elements: air, earth, fire, sky, water. Modern classification is based on physical and chemical properties.
2. Physical Nature of Matter
Matter is Made Up of Particles
Matter consists of particles, as shown by dissolving salt in water without changing water level. Particles spread throughout the water.
How Small Are These Particles?
Particles are tiny; a few crystals of potassium permanganate color a large volume of water through repeated dilution.
3. Characteristics of Particles of Matter
Particles Have Space Between Them
Sugar or salt particles fit into spaces between water particles when dissolved.
Particles Are Continuously Moving
Incense smell spreads, ink diffuses in water, showing particle motion increases with temperature.
Particles Attract Each Other
Force of attraction holds particles together, varying by matter type, as in breaking chains or substances.
4. States of Matter
Solid, Liquid, Gas
Solids have definite shape and volume; liquids have fixed volume but no shape; gases are compressible with no fixed shape or volume.
5. Change of State
Effect of Temperature and Pressure
Heating causes melting and boiling; pressure compresses gases to liquids.
Latent Heat
Latent heat of fusion and vaporization absorbed during state changes without temperature rise.
6. Evaporation
Evaporation is surface phenomenon below boiling point. Factors: surface area, temperature, humidity, wind speed. Causes cooling by absorbing energy.
Key Concepts and Definitions
Matter
Anything that occupies space and has mass.
Particles of Matter
Tiny units with space between, continuous motion, and attraction.
States of Matter
Solid: definite shape/volume; Liquid: fixed volume, no shape; Gas: no fixed shape/volume.
Melting Point
Temperature where solid becomes liquid at atmospheric pressure.
Boiling Point
Temperature where liquid becomes gas at atmospheric pressure.
Evaporation
Change of liquid to vapor below boiling point.
Important Facts and Figures
Questions and Answers from Chapter
Short Questions
Q1. Which of the following are matter? Chair, air, love, smell, hate, almonds, thought, cold, lemon water, smell of perfume.
Q2. Give reasons for the following observation: The smell of hot sizzling food reaches you several metres away, but to get the smell from cold food you have to go close.
Q3. A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?
Q4. What are the characteristics of the particles of matter?
Q5. Give reasons (a) A gas fills completely the vessel in which it is kept.
Q6. Give reasons (b) A gas exerts pressure on the walls of the container.
Q7. Give reasons (c) A wooden table should be called a solid.
Q8. Give reasons (d) We can easily move our hand in air but to do the same through a solid block of wood we need a karate expert.
Q9. Convert the following temperature to celsius scale: a. 300 K
Q10. Convert the following temperature to celsius scale: b. 573 K
Q11. What is the physical state of water at: a. 250°C
Q12. What is the physical state of water at: b. 100°C
Q13. For any substance, why does the temperature remain constant during the change of state?
Q14. Suggest a method to liquefy atmospheric gases.
Q15. Why does a desert cooler cool better on a hot dry day?
Medium Questions
Q1. The mass per unit volume of a substance is called density. (density = mass/volume). Arrange the following in order of increasing density – air, exhaust from chimneys, honey, water, chalk, cotton and iron.
Q2. (a) Tabulate the differences in the characteristics of states of matter.
Q3. (b) Comment upon the following: rigidity, compressibility, fluidity, filling a gas container, shape, kinetic energy and density.
Q4. Liquids generally have lower density as compared to solids. But you must have observed that ice floats on water. Find out why.
Q5. How does the water kept in an earthen pot (matka) become cool during summer?
Q6. Why does our palm feel cold when we put some acetone or petrol or perfume on it?
Q7. Why are we able to sip hot tea or milk faster from a saucer rather than a cup?
Q8. What type of clothes should we wear in summer?
Q9. Convert the following temperatures to the celsius scale. (a) 293 K (b) 470 K
Q10. Convert the following temperatures to the kelvin scale. (a) 25°C (b) 373°C
Q11. Give reason for the following observations. (a) Naphthalene balls disappear with time without leaving any solid.
Q12. Give reason for the following observations. (b) We can get the smell of perfume sitting several metres away.
Q13. Arrange the following substances in increasing order of forces of attraction between the particles— water, sugar, oxygen.
Q14. What is the physical state of water at— (a) 25°C (b) 0°C (c) 100°C ?
Q15. Give two reasons to justify— (a) water at room temperature is a liquid.
Long Questions
Q1. Give two reasons to justify— (b) an iron almirah is a solid at room temperature.
Q2. Why is ice at 273 K more effective in cooling than water at the same temperature?
Q3. What produces more severe burns, boiling water or steam?
Q4. Name A,B,C,D,E and F in the following diagram showing change in its state
Q5. Which of the following are matter? Chair, air, love, smell, hate, almonds, thought, cold, lemon water, smell of perfume.
Q6. Give reasons for the following observation: The smell of hot sizzling food reaches you several metres away, but to get the smell from cold food you have to go close.
Q7. A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?
Q8. What are the characteristics of the particles of matter?
Q9. Give reasons (a) A gas fills completely the vessel in which it is kept.
Q10. Give reasons (b) A gas exerts pressure on the walls of the container.
Q11. Give reasons (c) A wooden table should be called a solid.
Q12. Give reasons (d) We can easily move our hand in air but to do the same through a solid block of wood we need a karate expert.
Q13. Convert the following temperature to celsius scale: a. 300 K b. 573 K
Q14. What is the physical state of water at: a. 250°C b. 100°C ?
Q15. For any substance, why does the temperature remain constant during the change of state?
Interactive Knowledge Quiz
Test your understanding of Matter In Our Surroundings
Quick Revision Notes
Matter Particles
- Small size
- Spaces between
- Continuous motion
States
- Solid: Rigid
- Liquid: Fluid
- Gas: Compressible
Change of State
- Melting: 273K
- Boiling: 373K
- Sublimation
Evaporation
- Surface phenomenon
- Causes cooling
- Factors: Temp, wind
Exam Strategy Tips
- Focus on activities
- Understand latent heat
- Practice conversions
- Use diagrams
- Revise definitions
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