Matter in Our Surroundings Class 9 MCQ With Answers Set-2
Q11. Which of the following is NOT a property of gases?
A. No definite shape
B. No definite volume
C. Fluid
D. Compressible
Answer – C. Fluid
Explanation-Gases are not fluids, because they do not have a fixed volume or shape. The other three options are all properties of gases.
Q12. Which of the following is the fastest rate of diffusion?
A. Solids
B. Liquids
C. Gases
D. All are the same
Answer – C. Gases
Explanation-Gases have the fastest rate of diffusion because the particles of gases are moving the fastest and have the most space between them.
Q13. Which of the following is NOT a property of gases?
A. Highly compressible
B. No definite shape
C. No definite volume
D. Fluid
Answer – D. Fluid
Explanation-Gases are not fluids, because they do not have a fixed volume or shape. The other three options are all properties of gases.
Q14. Which of the following is the fastest rate of diffusion?
A. Solids
B. Liquids
C. Gases
D. All are the same
Answer – C. Gases
Explanation-Gases have the fastest rate of diffusion because the particles of gases are moving the fastest and have the most space between them.
Q15. Why is it possible to store a large volume of gas in a small cylinder?
A. Because gases are highly compressible
B. Because gases have no definite shape
C. Because gases have no definite volume
D. All of the above
Answer – A. Because gases are highly compressible
Explanation-Gases are highly compressible, meaning they can be squeezed into a smaller space without changing their state of matter. This is why it is possible to store a large volume of gas in a small cylinder.
Q16. How does the smell of cooked food reach our noses?
A. By diffusion of the aroma particles in the air
B. By convection of the air
C. By radiation of the heat
D. All of the above
Answer – A. By diffusion of the aroma particles in the air
Explanation-The smell of cooked food reaches our nose by diffusion of the aroma particles in the air. The aroma particles are released from the food and then diffuse in the air. The particles of the aroma eventually reach our nose, where they are detected by the olfactory receptors.
Q17. Which of the following is NOT a factor that affects the melting point of a solid?
A. Strength of the forces of attraction between the particles
B. Purity of the solid
C. Pressure
D. Temperature
Answer – D. Temperature
Explanation- Temperature does not affect the melting point of a solid. The other three options are all factors that affect the melting point of a solid.
Q18. What is the melting point of ice?
A. 0 °C
B. 100 °C
C. 273.15 K
D. 373.15 K
Answer – C. 273.15 K
Explanation-The melting point of ice is 273.15 K.
Q19. What is the process of melting called?
A. Fusion
B. Vaporization
C. Condensation
D. Solidification
Answer – A. Fusion
Explanation-The process of melting is called fusion.
Q20. Where does the heat energy go when a solid melts?
A. It is used to overcome the forces of attraction between the particles.
B. It is stored in the liquid.
C. It is released into the surroundings.
D. All of the above
Answer –A. It is used to overcome the forces of attraction between the particles.
Explanation-When a solid melts, the heat energy is used to overcome the forces of attraction between the particles. This is why the temperature of the solid remains the same during melting.
