Science MCQ Class 9, Chapter-1, Matter In Our Surroundings

NCERT based MCQ of Class 9th, Chapter-1, Matter In Our Surroundings with brief explanation for competitive exams like HTET, SSC and all other state competition exams. 

Along with MCQ, Chapter Key-Points for quick learning NCERT related facts are also discussed below. 

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Summary of the Chapter-1-Matter In Our Surroundings  with Key-Points:

• Matter is composed of tiny particles.
• Matter exists in three forms: solid, liquid, and gas.
• The strength of attraction between particles is strongest in solids, moderate in liquids, and weakest in gases.
• The space between particles and their kinetic energy are least in solids, moderate in liquids, and greatest in gases.
• In solids, particle arrangement is highly ordered, while in liquids, particles can slide past each other, and in gases, particles move randomly without any order.
• States of matter can be transformed by altering temperature or pressure.
• Sublimation refers to the direct transition from solid to gas without passing through the liquid state.
• Deposition is the direct change from gas to solid without going through the liquid state.
• Boiling is a bulk process where particles throughout the liquid turn into vapor.
• Evaporation is a surface process where particles on the surface gain enough energy to transition into vapor.
• The rate of evaporation is influenced by surface area, temperature, humidity, and wind speed.
• Evaporation results in cooling.
• Latent heat of vaporization is the energy needed to convert 1 kg of liquid to gas at its boiling point under atmospheric pressure.
• Latent heat of fusion is the energy required to change 1 kg of solid to liquid at its melting point.

NCERT Based MCQ with Explanation:

1) Which of the following is considered matter?

A) Love

B) Air

C) Smell

D) Thought

Explanation: Matter is anything that occupies space and has mass. Among the options, only air qualifies as matter because it is composed of particles that occupy space and have mass. Love, smell, and thought are not considered matter as they are not physical substances.

2) What is the smallest unit of matter?

A) Molecule

B) Atom

C) Cell

D) Electron

Explanation: Atoms are the basic units of matter, consisting of protons, neutrons, and electrons. Molecules are formed when atoms bond together, but atoms themselves are the fundamental building blocks.

3) According to ancient Indian philosophy, what are the five basic elements of matter?

A) Air, Water, Fire, Earth, Sky

B) Water, Fire, Metal, Wood, Air

C) Earth, Wind, Water, Metal, Ether

D) Air, Water, Metal, Wood, Fire

Explanation: Ancient Indian philosophers classified matter into five basic elements known as "Panch Tatva" — Air, Earth, Fire, Sky, and Water, which they believed constituted everything in the universe.

4) What happens to salt when it is dissolved in water?

A) It reacts with water to form a new substance.

B) It sinks to the bottom.

C) It disappears due to the heat.

D) Its particles mix with the water particles.

Explanation: When salt dissolves in water, its particles spread out and occupy the spaces between water particles, demonstrating that matter is made up of particles.

5) Which characteristic of matter allows a diver to move through water?

A) Matter has mass.

B) Particles of matter have space between them.

C) Particles of matter attract each other.

D) Particles of matter are continuously moving.

Explanation: The ability of a diver to move through water is due to the spaces between water particles, which allow for movement and fluidity.

6) What is the boiling point of water in Kelvin?

A) 100 K

B) 273 K

C) 373 K

D) 473 K

Explanation: The boiling point of water is 100°C, which is equivalent to 373 K on the Kelvin scale (0°C = 273 K, so 100°C = 273 + 100 = 373 K).

7) Which of the following best explains why solids have a definite shape?

A) Particles are free to move.

B) Particles are packed closely in fixed positions.

C) Particles are loosely packed.

D) Particles can slide over each other.

Explanation: Solids have a definite shape because their particles are tightly packed in a fixed, orderly arrangement, restricting their movement and making the solid rigid.

8) Which process describes the direct change of a solid to a gas?

A) Condensation

B) Vaporization

C) Sublimation

D) Fusion

Explanation: Sublimation is the process where a solid changes directly to a gas without passing through the liquid state. Examples include camphor and dry ice (solid CO₂).

9) Why do gases exert pressure on the walls of their container?

A) Gases are weightless.

B) Gas particles are stationary.

C) Gas particles collide with each other and the container walls.

D) Gas particles move in circular paths.

Explanation: Gases exert pressure because their particles are in constant random motion, colliding with each other and the walls of the container, exerting force.

10) Which state of matter has the highest kinetic energy?

A) Solid

B) Liquid

C) Gas

D) Plasma

Explanation: In the gaseous state, particles have the highest kinetic energy due to their rapid, random movement and the large spaces between them compared to solids and liquids.

11) Which of the following statements about the particles of matter is true?

A) Particles of matter are always at rest.

B) Particles of matter are always moving.

C) Particles of matter are only moving when heated.

D) Particles of matter move only in solids.

Explanation: Particles of matter are in constant motion due to their kinetic energy, regardless of the state they are in (solid, liquid, or gas). This movement is more pronounced in gases and less in solids.

12) What happens to the rate of diffusion when the temperature increases?

A) It decreases.

B) It remains the same.

C) It increases.

D) It stops completely.

Explanation: An increase in temperature provides particles with more kinetic energy, causing them to move faster and mix more quickly, thus increasing the rate of diffusion.

13) Which physical state of matter has a fixed shape and volume?

A) Solid

B) Liquid

C) Gas

D) Plasma

Explanation: Solids have a definite shape and volume due to tightly packed particles in fixed positions, allowing minimal movement and deformation under normal conditions.

14) Which of the following best describes why gases can be compressed easily?

A) Gases have large spaces between particles.

B) Gases have very strong intermolecular forces.

C) Gases have high densities.

D) Gases have fixed volumes.

Explanation: The particles in gases are far apart and move freely, which allows them to be easily compressed compared to solids and liquids.

15) What happens to the kinetic energy of particles when a substance changes from solid to liquid?

A) It decreases.

B) It remains the same.

C) It increases.

D) It fluctuates randomly.

Explanation: During the transition from solid to liquid, particles absorb heat, increasing their kinetic energy, which causes them to move more freely and overcome some of the forces holding them in fixed positions.

16) Which property of matter allows a solid to retain its shape?

A) Fluidity

B) Rigidity

C) Compressibility

D) Diffusion

Explanation: Rigidity is the property that allows solids to maintain their shape and resist deformation due to the strong attraction between their particles.

17) What is the process of a liquid changing into a gas called?

A) Condensation

B) Freezing

C) Vaporization

D) Sublimation

Explanation: Vaporization is the process in which a liquid changes into a gas, typically when heat is applied, causing particles to gain enough energy to break free from the liquid state.

18) Which of the following substances is an example of sublimation?

A) Water

B) Iron

C) Camphor

D) Salt

Explanation: Sublimation is the process by which a substance changes directly from a solid to a gas without passing through the liquid state. Camphor is a common example.

19) What type of change occurs when water freezes?

A) Physical change

B) Chemical change

C) Biological change

D) Nuclear change

Explanation: Freezing is a physical change because it only involves a change in the state of matter (liquid to solid) without altering the chemical composition of the water.

20) What is the main reason why gases have no definite shape or volume?

A) Particles are tightly packed.

B) Particles are stationary.

C) Particles move randomly at high speeds.

D) Particles are arranged in a fixed pattern.

Explanation: Gases have no definite shape or volume because their particles are in constant, rapid, random motion, allowing them to spread out and fill any available space.