NCERT Solutions for Class 9 Science Chapter 1 Matter in Our Surroundings

NCERT Solutions for Class 9 Science Chapter 1 Matter in Our Surroundings help students understand the fundamental concept of matter, its nature, and its physical states. This chapter explains how matter exists in different forms such as solids, liquids, and gases, and how changes in temperature and pressure can affect its state.

Prepared according to the latest CBSE Class 9 Science syllabus, these solutions provide clear and structured answers to all textbook questions. Practicing these solutions helps students strengthen their concepts and perform better in exams.

NCERT Solutions for Class 9 Science Chapter 1 Matter in Our Surroundings

Matter in Our Surroundings
Easy
Q.
Convert the following temperatures to the Celsius scale.
(a) 293 K    (b) 470 K
Matter in Our Surroundings
Easy
Q.
Convert the following temperatures to the Kelvin scale.
(a) 25°C     (b) 373°C
Matter in Our Surroundings
Medium
Q.
Give reason for the following observations.
(a) Naphthalene balls disappear with time without leaving any solid.
(b) We can get the smell of perfume sitting several metres away.
Matter in Our Surroundings
Easy
Q.
Arrange the following substances in increasing order of forces of attraction between the particles— water, sugar, oxygen.
Matter in Our Surroundings
Medium
Q.
What is the physical state of water at—
(a) 25°C   (b) 0°C   (c) 100°C ?
Matter in Our Surroundings
Medium
Q.
Give two reasons to justify—
(a) Water at room temperature is a liquid.
(b) an iron almirah is a solid at room temperature.
Matter in Our Surroundings
Easy
Q.
Why is ice at 273 K more effective in cooling than water at the same temperature?
Matter in Our Surroundings
Medium
Q.
What produces more severe burns, boiling water or steam?
Matter in Our Surroundings
Medium
Q.
Name A, B, C, D, E and F in the following diagram showing change in its state
 

NCERT Solutions for Class 9 Science Chapter 1 Matter in Our Surroundings

Q1. Which of the following are matter?

Chair, air, love, smell, hate, almonds, thought, cold, cold drink, smell of perfume.
Ans: Matter includes chair, air, almonds, cold drink, smell of perfume because they have mass and occupy space. Love, hate, thought, and cold are not matter.

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.

Ans: At higher temperature, particles move faster, so diffusion is faster. Hence, smell of hot food spreads quickly.

Q3. A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?

Ans: It shows that particles of matter have weak intermolecular forces and can move easily.

Q4. What are the characteristics of particles of matter?

Ans:

  • Particles of matter have space between them
  • They are continuously moving
  • They attract each other

Q5. The mass per unit volume of a substance is called density. Arrange the following in increasing order of density: air, exhaust from chimneys, honey, water, chalk, cotton, and iron.

Ans:
Air < Exhaust < Cotton < Water < Honey < Chalk < Iron

Q6. Why does a desert cooler cool better on a hot dry day?

Ans: On a hot dry day, evaporation is faster due to low humidity, leading to better cooling.

Q7. How does evaporation cause cooling?

Ans: During evaporation, particles absorb heat from surroundings, causing cooling.

Q8. What factors affect evaporation?

Ans:

  • Surface area
  • Temperature
  • Humidity
  • Wind speed

FAQs – Class 9 Science Chapter 1 Matter in Our Surroundings

Q1. What is matter?
Matter is anything that has mass and occupies space.

Q2. What are the three states of matter?
The three states are solid, liquid, and gas.

Q3. What is diffusion?
Diffusion is the process of intermixing of particles on their own.

Q4. What is evaporation?
Evaporation is the process of change of liquid into vapour at any temperature.

Q5. Why is this chapter important for exams?
This chapter forms the foundation of chemistry concepts and includes important conceptual and reasoning-based questions.