CBSE Class 9 Science Matter In Our Surroundings MCQs Set C

Question: A form of matter has no fixed shape but it has a fixed volume. An example of this form of matter is :
a) krypton
b) kerosene
c) carbon steel
d) carbon dioxide
Answer: b

Question: When a crystal of potassium permanganate is placed at the bottom of water in a beaker, the water in the whole beaker turns purple on its own, even without stirring. This is an example of :
a) distribution
b) intrusion
c) diffusion
d) effusion
Answer: c

Question: When a gas jar full of air is placed upside down on a gas jar full of bromine vapours, the red-brown vapours of bromine from the lower jar go upward into the jar containing air. In this experiment :
a) air is heavier than bromine
b) both air and bromine have the same density
c) bromine is heavier than air
d) bromine cannot be heavier than air because it is going upwards against gravity
Answer: c

Question: Which of the following statement is incorrect ?
a) the particles of matter are very, very small
b) the particles of matter attract one another
c) the particles of some of the matter are moving constantly
d) the particles of all the matter have spaces between them
Answer: c

Question: The best evidence for the existence and movement of particles in liquids was provided by :
a) John Dalton
b) Ernest Rutherford
c) J.J. Thomson
d) Robert Brow
Answer: d

Question: Which one of the following statements is not true ?
a) the molecules in a solid vibrate about a fixed position
b) the molecules in a liquid are arranged in a regular pattern
c) the molecules in a gas exert negligibly small forces on each other, except during collisions
d) the molecules of a gas occupy all the space available
Answer: b

Question: A few substances are arranged in the increasing order of ‘forces of attraction’ between their particles. Which one of the following represents the correct arrangement ?
a) water, air, wind
b) air, sugar, oil
c) oxygen, water, sugar
d) salt, juice, air
Answer: c

Question: Out of the following, an example of matter which can be termed as fluid is :
a) carbon
b) sulphur
c) oxygen
d) phosphorus
Answer: c

Question: Which one of the following statement is correct in respect of fluids ?
a) only gases behave as fluids
b) gases and solids behave as fluids
c) gases and liquids behave as fluids
d) only liquids are fluids
Answer: c

Question: When a gas jar containing colourless air is kept upside down over a gas jar full of brown-coloured bromine vapour, then after some time, the brown colour of bromine vapour spreads into the upper gas jar making both the gas jars appear brown in colour. Which of the following conclusion obtained from these c observations is incorrect ?
a) bromine vapour is made of tiny particles which are moving
b) air is made up of tiny particles which are moving
c) the particles of bromine are moving but those of air are not moving
d) even though bromine vapour is heavier than air, it can move up against gravity
Answer: c

Question: In which of the following conditions, the distance between the molecules of hydrogen gas would increase ?
(i) increasing 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)
Answer: c

Question: Honey is more viscous than water. Can you suggest why ?
Answer: The force of attraction between the particles of honey is much more than the force of attraction between the particles of water

Question: Arrange the following substances in increasing order of force of attraction between their particles (keeping the substance having the minimum force of attraction first) : Water, Sugar, Oxygen
Answer: Oxygen < Water < Sugar

Question: Name one property of liquids and gases which tells us that their molecules are moving constantly.
Answer:Diffusion

Question: Name two processes which provide the best evidence for the motion of particles in matter.
Answer:Diffusion and Brownian motion

Question: When sugar is dissolved in water, there is no increase in the volume. Which characteristic of matter is illustrated by this observation ?
Answer: The particles of a liquid (here water) have spaces between them

Question: Which single term is used to describe the mixing of copper sulphate and water kept in a beaker, on its own ?
Answer: Diffusion

Fill in the following blanks with suitable words :

Question: The smell of perfume gradually spreads across a room due to…………
Answer:diffusion

Question: The best evidence that the particles of matter are constantly moving comes from the studies of ………… and …………
Answer: diffusion ; Brownian motion

Question: Solid, liquid and gas are the three…………of matter.
Answer:states

Question: The arrangement of particles is less ordered in the……………….state. However, there is no order in the……….state.
Answer:liquid ; gaseous

Question: At room temperature, the forces of attraction between the particles of solid substances are…………….than those which exist in the gaseous state.
Answer: much more

Question: A piece of chalk can be broken into small particles by hammering but a piece of iron cannot be broken into small particles by hammering. Which characteristic of the particles of matter is illustrated by these observations ?
Answer: The particles of matter attract one another (some attract less as in the case of chalk but some attract much more as in the case of iron)

Question: 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 particles of matter are constantly moving in all the directions

Question: Which of the two diffuses slower : bromine vapour into air or copper sulphate into water ?
Answer: Copper sulphate into water

Question: Even two or three crystals of potassium permanganate can impart colour to a very large volume of water. Which characteristic of particles of matter is illustrated by this observation ?
Answer: Each crystal of potassium permanganate must be made up of millions of small particles

Question: What is the scientific name of particles which make up matter ?
Answer:Atoms or Molecules

Question: If the fish is being fried in a neighbouring home, we can smell it sitting in our own home. Name the process which brings this smell to us.
Answer:Diffusion

Question: A bottle of perfume was opened in a room. The smell of its vapours spread in the entire room. Name the property of gases which is responsible for this behaviour of perfume vapours.
Answer:Diffusion

Question: State whether the following statement is true or false :
Red-brown bromine vapour diffuse into air in a gas jar but the colourless air molecules do not diffuse into bromine vapour.
Answer: False

Question: What is the general name of :
a) rigid form of matter ?
b) fluid forms of matter ?
Answer:
a) Solid
b) Liquid and Gas