Tuesday, 30 March 2021

CBSE Class 9 - Chemistry - Matter in Our Surroundings - 1 Mark Questions and Answers (#class9Chemistry)(#class9Science)(#eduvictors)

CBSE Class 9 - Chemistry - Matter in Our Surroundings - 1 Mark Questions and Answers 

CBSE Class 9 - Chemistry - Matter in Our Surroundings - 1 Mark Questions and Answers (#class9Chemistry)(#class9Science)(#eduvictors)


Q1: What are the conditions for 'something' to be called 'matter'?

Answer: The main conditions for something to be matter are, it should:

(a) occupy space and

(b) have mass


Q2:  Name the state of matter in which particles just move around randomly because of the very weak force of attraction.

Answer: Gaseous state


Q3: Name two processes that provide the best evidence for the motion of particles in matter.

Answer: Diffusion and Brownian motion provide the best evidence about the random motion of particles in matter.


Q4: Give two examples of practical applications which are based on the high compressibility of gases.

Answer: CNG, LPG.


Q5: Name the property of gases that helps aquatic plants and animals to survive in water.

Answer: Gases diffuse or are soluble in water.


Q6: When sugar is dissolved in water, there is no increase in volume. Which characteristic of matter is illustrated by this observation?

Answer: The absence of an increase in the volume of water on the dissolution of sugar into it, describes the following characteristics of the matter:

(a) Matter is made up of very, very small particles.

(b) Particles of matter have spaces between them.


Q7: A substance has a finite volume but not a definite shape. Write the physical state of a substance.

Answer: Liquid state


Q8: When an incense stick (agarbatti) is lighted in one corner of a room its fragrance spreads in the whole room quickly. Which characteristic of the particles of matter is illustrated by this observation?

Answer: The spreading of the fragrance of incense stick from a corner to the whole room indicates that particles of matter keep moving from higher to lower concentration (called diffusion).


Q9: Why do liquids have mostly lower density than solids?

Answer: Liquids have less force of attraction between molecules ie, less mass and more volume as compared to solids.


Q10: Name the process by which a drop of ink spreads in a beaker of water.

Answer: Diffusion is the process by which a drop of ink spreads in a beaker containing water.


Q11: Out of solids, liquids and gases, which one has:

(a) maximum movement of particles?

(b) maximum interparticle attractions?

(c) minimum spaces between particles?


Answer: Among solids, liquids and gases;

(a) A gas has a maximum movement of particles.

(b) A solid has maximum inter-particle attraction.

(c) A solid has minimum space between the particles.


Q12: Identify the name of the material which has no fixed shape but a fixed volume :

Wood, a piece of iron, oxygen and water.


Answer: Water.


Q13: A substance has no mass; can we consider it as matter?

Answer: No


Q14: Mention two factors that need to be varied to liquify atmospheric gases.

Answer: Temperature and pressure


Q15: A substance has neither a fixed shape nor a fixed volume. State whether it is a solid, a liquid or a gas.

Answer: Gases have neither a fixed shape nor a fixed volume; they acquire the shape and volume of the vessel in which they are kept.


Q16: Write the full forms of the following

(a) LPG

(b) CNG


Answer: LPG: Liquefied Petroleum Gas

CNG: Compressed Natural Gas


Q17: A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?

Answer: Particles of water are held together by weak forces of attraction. It is through these forces of attraction that the diver cuts through water in the swimming pool.


Q18: How can we liquefy gases?

Answer: We can liquify gases by applying pressure and reducing temperature.


Q19: A wooden chair is solid at room temperature. Give two reasons.

Answer: A wooden chair is solid at room temperature because:

(i) it has a definite shape and volume,

(ii) it cannot be compressed.


Q20: When a gas jar containing air is inverted over a gas jar containing bromine vapour, the red-brown bromine vapour diffuses into the air. Explain how bromine vapour diffuses into the air.


Answer: Both air and bromine vapour are made up of tiny moving particles, which collide with each other and bounce about in all directions due to which both the gas particles mix uniformly. This is an example of diffusion.


Q21: Why does a gas exert pressure?

Answer: When gas is stored in a container, the fast-moving particles of the gas collide with each other and with the walls of the container; thus, exerting pressure on the walls of the container.


Q22: Convert the temperature of 573 K to the Celsius scale.

Answer: Temp. on Celsius scale = Temp. on Kelvin scale – 273

573 – 273 = 300° C


Q23: What is meant by the latent heat of fusion?

Answer: The amount of heat energy that is required to change 1 kg of a solid into liquid at atmospheric pressure at its melting point is known as the latent heat of fusion.


Q24: Name the phenomenon of changing a liquid into vapours at a temperature even below its boiling point.

Answer: Evaporation


Q25: What is the name of the process in which a solid turns directly into a gas?

Answer: Sublimation


👉See Also:

Ch 1 - Matter in Our Surroundings (Q & A)
Ch 1 - Matter in our Surroundings (Questions asked in CBSE papers - Unsolved)
Ch1 - Matter in our Surroundings (Unit Objective Test)
Ch1 - Matter in Our Surroundings (MCQs-1)
Ch1 - Matter In Our Surroundings (Question Bank)
Ch1 - Matter In Our Surroundings (Unit Test Paper)
Ch1 - Matter in Our Surroundings (MCQs-2)
Ch1 - Matter in Our Surroundings (Reasoning Questions)
Ch1 - Matter in Our Surroundings (Revision Assignment)
Ch1 - Matter in Our Surroundings (Revision Assignment-2)
Ch1 - Matter in Our Surroundings (Short Q & A)
Ch1 - What is the Kinetic Theory Of Matter?





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