IMPORTANT QUESTIONS FROM CLASS 9 CHAPTER 'IS MATTER AROUND US PURE?'

 

MCQs

01. Rusting of an article made up of iron is called

(a) corrosion and it is a physical as well as chemical change

(b) dissolution and it is a physical change

(c) corrosion and it is a chemical change

(d) dissolution and it is a chemical change

Answer: (c) corrosion and is a chemical change

02. If we burn graphite,

(a)  the residue will be left

(b)  no residue will be left

(c)  it will not burn

(d)  it will change into a diamond.

Answer: (b) no residue will be left

03. Tincture of iodine has antiseptic properties. This solution is made by dissolving

(a) iodine in potassium iodide
(b) iodine in vaseline
(c) iodine in water
(d) iodine in alcohol

Answer: (d) iodine in alcohol

04. Which of the following are homogeneous in nature?
(i) ice
(ii) wood
(iii) soil
(iv) air
(a) (i) and (iii)
(b) (ii) and (iv)
(c) (i) and (iv)
(d) (iii) and (iv)

Answer: (c) (i) and (iv)

05. When two liquids do not mix, they form two separate layers and are known as

(a) Miscible liquids

(b) Immiscible liquids

(c) Saturated liquids

(d) Supersaturated liquids

Answer: (b) Immiscible liquids

06. Mercury and bromine are both

(a) liquid at room temperature
(b) solid at room temperature
(c) gases at room temperature
(d) both (a) and (b)

Answer: (a) liquid at room temperature

07. What is the name of the non-metal which exists in a liquid state at room temperature?

(a) Mercury

(b) Bromine

(c) Sodium

(d) Potassium

Answer: (b) Bromine

08. Diamond is lustrous because

(a)  it is colorless

(b)  it is hard

(c)  it is pure

(d)  its refractive index is high

Answer: (c) its refractive index is high

09. In the tincture of iodine, find the solute and solvent?

(a) alcohol is the solute and iodine is the solvent

(b) iodine is the solute and alcohol is the solvent

(c) any component can be considered as solute or solvent

(d) tincture of iodine is not a solution

Answer: (b) iodine is the solute and alcohol is the solvent

10. Brass is a solution of molten copper in

(a)  solid zinc

(b)  molten zinc

(c)  gaseous zinc

(d)  molten tin

Answer: (b) molten zinc

11. The continuous zig-zag movement of colloidal particles in a dispersion medium is called 

(a) Dispersion

(b) Tyndall effect

(c) Brownian movement

(d) Oscillation

Answer: (c) Brownian movement

12. Which of the following non-metal is a good conductor of electricity?

(a) Aluminium

(b) Silicon

(c) Graphite

(d) Gold

Answer: (c) Graphite

13. Brass is a

(a)  Compound

(b)  Element

(c)  Homogeneous mixture

(d)  Heterogeneous mixture

Answer: (c) Homogeneous mixture

14. Purity of a solid substance can be checked by its:

(a) Boiling point

(b) Solubility in water

(c) Melting point

(d) Solubility in alcohol

Answer: (c) Melting point

15. A student is given a mixture of iron filings and sulfur in the ratio of 1: 2 by weight. He was then asked to heat the mixture over a flame and to observe the color change. The student will observe that the mixture becomes:

(a)Yellow

(b) Grey

(c) Black

(d) Orange

Answer: (c) Black

16. A sample contains two substances and has uniform properties. The sample is:

(a) A heterogeneous mixture
(b) An element
(c) A compound
(d) A homogeneous mixture

Answer: (d) A homogeneous mixture

17. Physical properties of a mixture:

(a) Depend on the volume of the substance
(b) Vary with the amount of substance
(c) Depend on the organization of the substance
(d) Vary depending upon its components

Answer: (d)  Vary depending upon its components

18. The fine particles of an insoluble substance uniformly dispersed throughout a gas or liquid is called 

(a) suspension 

(b) precipitate 

(c) colloidal solution 

(d) impurity

Answer: (c) colloidal solution 

19. The amount of the solute present in the saturated solution at this temperature is called its

(a) Unsaturation 
(b) Diffusion 
(c) Collusion 
(d) Solubility 

Answer: (d) solubility

Answer in one word

01. The first scientist to use the term element- 

Answer: Robert Boyle in 1661.

02. Who was the first to establish an experimentally useful definition of an element-

Answer: Antoine L. Lavoisier, a French chemist

03. Metalloids are also called- 

Answer: semi-metals

04. The property which allows the metals to be hammered into thin sheets without breaking-

Answer: Malleability

05. The property which allows metals to be stretched into thin wires without breaking-

Answer: Ductility

06. The property of non-metals due to which they break into pieces on hammering is called-

Answer: Brittleness

07. The most ductile metal is -

Answer: Gold and platinum are the earth’s most ductile metals, but gold has a significantly greater ductility than platinum.

08. The most malleable metal is-

Answer: Gold

09. The best conductor of heat and electricity- 

Answer: Silver

10. A metal which is the poorest conductor of heat-

Answer: Lead

11. Metals that are soft and have low densities and melting points-

Answer: Sodium and Potassium

12. A metal which is in a liquid state at room temperature-

Answer: Mercury

13. A metal that has a low melting point that starts melting in hand-

Answer: Gallium

14. All the metals have a silver or grey color except these two metals-

Answer: Gold and Copper

15. A non-metal which is a good conductor of heat -

Answer: Diamond

16. A non-metal which is a good conductor of electricity- 

Answer: Graphite

17. A non-metal which is the hardest natural substance- 

Answer: Diamond

18. A non-metal that has a lustrous appearance and has high density- 

Answer: Iodine

19. A non-metal which is liquid at room temperature-

Answer: Bromine 

20. A non-metal that has a very high melting point- 

Answer:  Graphite

21. Examples of metalloids are-

Answer: Boron (B), Silicon (Si), Germanium(Ge), etc.

22. What is universal solvent-

Answer: Water

23.  What is the solvent in an aqueous solution-

Answer: Water

24. Gases always mix together to form which type of mixture-

Answer: homogeneous mixture