Chapter 1. MATTERS IN OUR SURROUNDS

Class 9 Science Examplar Chepter 1: MATTER IN OUR SURROUNDINGS Choose the correct answers

Q1 . Which of the following are matter ?

(A) Air

(B) Love

(C) Smell

(D) Thought

Ans : (A) Air

Q2. Which of the following are not the characteristics of the particles of matter ?

(A) Particles of matter have space between them .

(B) Particles of matter are continuously moving .

(C) Particles of matter attract each other .

(D) The state of matter can not be changed by changing temperature or pressure .

Ans : (D) The state of matter can not be changed by changing temperature or pressure .

Q3. The density of water is maximum at :

 (A) 0° C    

(B) 100° C   

(C) 4° C    

(D) 273 K

Ans :  (C) 4° C    

Q4. The melting point of ice is :

(A) 273° C   

(B) 273 K    

(C) 373° C   

(D) 373 K

Ans : (B) 273 K

Q5. Which one of the following sets of phenomena would increase on raising the temperature ?

(A) Diffusion , evaporation , compressions of gases .

(B) Evaporation , compression of gases , solubility .

(C) Evaporation , diffusion , expansion of gases .

(D) Evaporation , solubility , diffusion , compression of gases .

Ans : (C) Evaporation , diffusion , expansion of gases .

Q6. The property to flow is unique to fluids . Which one of the following statements is correct ?

(A) Only gases behave like fluids

(B) Gases and solids behave like fluids

(C) Gases and liquids behave like fluids

(D) Only liquids are fluids

Ans : (C) Gases and liquids behave like fluids

Q7. During summer , water kept in an earthen pot becomes cool because of the phenomenon of ;

(A) diffusion

(B) transpiration

(C) osmosis

(D) evaporation

Ans : (D) evaporation

Q8. A few substances are arranged in the increasing order of ‘ force of attraction ’ between their particles . Which one of the following represents a correct arrangement ?

(A) Water , air , wind

(B) Air , sugar , oil

(C) Oxygen , water , sugar

(D) Salt , juice , air

Ans : (C) Oxygen , water , sugar

Q9. On converting 25°C , 38°C and 66°C to Kelvin scale , the correct sequence of temperature will be

(A) 298K , 311K and 339K

(B) 298K , 300K and 338K

(C) 273K , 278K and 543K

(D) 298K , 310K and 338K

Ans : (A) 298K , 311K and 339K

Q10 . Choose the correct statement of the following :

(A) conversion of solid into vapours without passing through the liquid state is called vapourisation.

(B) conversion of vapours into solid without passing through the liquid state is called sublimation .

(C)  conversion of vapours into solid without passing through the liquid state is called freezing .

(D) Conversion of solid into liquid is called sublimation .

Ans : (B) conversion of vapours into solid without passing through the liquid state is called sublimation .

Q8. The boiling points of diethyl ether , acetone and n-butyl alcohol are 35°C , 56°C and 118°C respectively . Which one of the following correctly represents their boiling points in Kelvin scale ?

(A) 306K , 329K , 391K

(B) 308K , 329K , 392K

(C) 308K , 329K , 391K

(D) 309K , 392K , 308K

Ans : (C) 308K , 329K , 391K

[35+273 = 308k ; 56+273 = 329K ; 118+273 = 391]

9. Which condition out of the following will increase the evaporation of water ?

(A) Increase in temperature of water .

(B) Decrease in temperature of water .

(C) Less exposed surface area of water .

(D) Adding common salt to water .

Ans : (A) Increase in temperature of water .

Q10. In which of the following conditions, the distance between the molecules of hydrogen gas wold increase ?

(i) Increase pressure on hydrogen contained in a closed container .

(ii) Some hydrogen gas leaking out of the container .

(iii) Increasing the volume of the container of hydrogen gas .

(iv) Adding more hydrogen gas to the container without increasing the volume of the container .

(A) (i) and (iii)

(B) (i) and (iv)

(C) (ii) and (iii)

(D) (ii) and (iv)

Ans :  (C) (ii) and (iii)

Q11. The physical state of water at 250°C , then it is :

(A) gas

(B) Solid

(C) Liquid

(D) Both solid and liquid

Ans : (A) gas

Q12. The Celsius scale of 573 K temperature is :

(A)  273°C

(B) 373°C

(C) 300°C

(D) 473°C

Ans : (C) 300°C

Q13. The temperature at which a solid melts to become a liquid at the atmospheric pressure is called its  .

(A) Boiling point

(B) Melting point

(C) Fusion

(D) Sublimation

Ans : (B) Melting point  .

Q14. The Kelvin scale of 250°C temperature is :

(A) 273K

(B) 373K

(C) 473K

(D) 520K

Ans :  (D) 520K

Q15.  Which of the following statement is not correct ?

(i) Liquids have no fixed shape but have a fixed volume .

(ii) Gases are highly compressible as compared to solids and liquids .

(iii) Solids have a tendency to maintain their shape when subjected to outside force .

(iv) Liquids flow and change shape, so they are rigid but can be called fluid .

(A) (i) , (ii) and (iv)

(B) (ii) , (iii) and (iv)

(C) (i) , (ii) and (iii)

(D) (i) , (iii) and (iv)

Ans : (C) (i) , (ii) and (iii)

[Liquids flow and change shape , so they are not rigid but can be called fluid . ]

Q16. A change of state directly from solid to gas without changing into liquid state is  called  .

(A) Sublimation .

(B)  dry ice

(C) fusion

(D) latent heat .

Ans : (A) Sublimation .

Q17. The S.I. unit of density is :

(A) 

(B) 

(C) 

(D) 

Ans : (A) 

[The S.I. unit of density is  . ]

Q18. The physical state of water at 0°C , then it is :

(A) Liquid

(B) Liquid and vapour

(C) Solid or liquid

(D) gas

Ans :  (C) Solid or liquid

Q19. Evaporation of a liquid occurs at –

(A) boiling point

(B) a fixed temperatures

(C) at temperature lower than boiling point

(D) at all temperatures

Ans : (D) at all temperatures

Q20. The fusion is the process in which

(A) Gas changes into solid .

(B) Solid changes into gas .

(C) solid changes into liquid .

(D) Liquid changes into solid .

Ans : (C) solid changes into liquid .

Q21 . At normal pressure(1 atmosphere) the boiling point of water is :

(A) 100°C

(B) 110°C

(C) 273°C

(D)  200°C

Ans : (A) 100°C

Class 9 Science Examplar Chepter 1 : MATTER IN OUR SURROUNDINGS Fill in the blanks :

Q22.   Causes cooling .

Ans : Evaporation .

Q23.  is a bulk phenomenon .

Ans : Boiling .

Q24. Evaporation of a liquid at room temperature leads to a  effect .

Ans : Cooling .

Q25. At room temperature the forces of attraction between the particles of solid substance are  than those which exist in the gaseous state .

Ans : Stronger .

Q26. The arrangement of particles is less ordered in the  state . However, there is no order in the  state .

Ans :  Liquid , gaseous

Q27.  is the change of solid state directly to vapour state without going through the  state .

Ans : Sublimation , liquid

Q28. The phenomenon of change of a liquid into the gaseous state at any temperature below its boiling point is called  .

Ans : Evaporation .