79 + Interview Questions in MATTER-IN-OUR-SURROUNDINGS IN GENERAL AWARENESS Page 1 InterviewSolution

1.	`25^(@)C` temperature is equal toA. `298.15K`B. `25K`C. `77^(@)F`D. `300K`
Answer» Correct Answer - A::C

Discussion

2.	Give reason for the following observations. (a) Naphthalene balls disappear with time without leaving any solid. (b) We can get the smell of perfume sitting several metres away.
Answer» (a) Naphthalene balls disappear with time without leaving any solid because of they undergoes sublimation easily i.e., the change of state of naphthalene from solid to gas takes place easily (b) Perfumes have high degree of vaporisation and its vapour diffuses into the air easily. Therefore we can get the smell of perfume sitting several metres away.

Discussion

3.	Why are gases highly compressible ?
Answer» Because the interparticle empty spaces are very large. When a gas is compressed, these spaces decrease. The particles or molecules of gas come closer.

Discussion

4.	Name the state of matter that : (i) has definite mass, volume and shape. (ii) has no definite volume and shape (iii) has minimum inter particle attraction. (iv) has maximum inter particle attraction.
Answer» (i) solid state (ii) gaseous state (iii) gaseous state (iv) solid state

Discussion

5.	Why are gases highly compressible while solids are almost incompressible ?
Answer» In the gases, the inter particle or inter molecular spaces are very large. These can be decreased to a large extent on applying pressure. Therefore, the gases are highly compressible. However, in solids these spaces are very small and cannot be decreased be decreased any more on applying pressure. Therefore, the solids are almost incompressible.

Discussion

6.	Melting points of three solids X, Y and Z are 298 K, 314K and 398 K respectively. Arrange these in increasing order of inter particle forces of attraction.
Answer» Please remember that greater the melting point temperature of a solid, more is the magnitude of interparticle forces. The correct is `X lt Y lt Z`.

Discussion

7.	A cooler is quite effective on a hot and dry day. Explain.
Answer» Under the conditions, the humidity level in the atmosphere is quite low and the evaporation rate of water is expected to be high. Since cooling is caused during evaporation, the air which escapes from the cooler is compartively cold under these conditions. Therefore, is quite effective on a hot and dry day.

Discussion

8.	Give reasons for the following observations : The smell of hot sizziling food reaches you several metres away but to get the smell from cold food, you have to go close.
Answer» The smell of food reaches us by the process of diffusion of gases (released by the food) into the air. The rate of diffusion of hot gases into air is faster than that of cold gases. So, the smell of hot sizzling food reaches us quickly even when we are several metres away because the rate fo diffusion of hot gases (released by the hot sizzling food) is much faster than the rate of diffusion of cold gases released by the cold food.

Discussion

9.	In the following example state which factor is responsible for the change in rate of evaporation and is effective. `{:(i,"Colthes dry faster on a windy day",(ii),"Wet clothes dry faster on spreding them"),(iii,"Clothes dry faster in sun than in shade",(iv),"Clothes take a longer time to dry on a rainy day"):}`
Answer» `{:(i,"Increase in speed of the wind",(ii),"Increase in surface area available for evaporation"),(iii,"Increase in temperature",(iv),"Increase of humidity in wet air"):}`

Discussion

10.	Can we regard high fever as matter ?
Answer» High fever is a feeling only. It cannot be regarded as matter.

Discussion

11.	Why do not solids possess fluidity ?
Answer» Fluidity means tendency to flow. The constituents in the solids are very closely packed and interparticle forces are quite strong. Therefore, solids have hardly any fluidity.

Discussion

12.	Dry ice isA. solid carbon dioxide .B. solid carbon monoxideC. liquid ammoniaD. ordinary ice
Answer» Correct Answer - A

Discussion

13.	Fill in the blanks : (a) Evaporation of a liquid at room temperature leads to a _____ effect. (b) At room temperature, the forces of attraction between the particles of solid substances are _____ than those which exist in the gaseous state. (c ) The arrangement of particles is less ordered in the _____ state. However, there is no order in the _____ state. (d) ____ is the change of gaseous state directly to solid state without going through the ____ state. (e ) The phenomenon of change of a liquid into the gaseous state at any temperature below its boiling point is called ____ .
Answer» (a) cooling (b) strogner (c ) liquid, gaseous (d) freezing, liquid (e ) evaporation.

Discussion

14.	Name the process associated with the following (a) Dry ice is kept at room temperature and at one atmospheric pressure. (b) A drop of link placed on the surface of water contained in a glass spreads throughout the water. (c) A potassium permanganate crystal is in a beaker and water is poured into the beaker with stirring. (d) A acetone bottle is left open and the bottle becomes empty. (e) Milk is churned to separate cream from it. (f) Settling of sand when a mixture of sand and water is left undisturbed for some time. (g) Fine beam of light entering through a small hole in a dark room. Illuminates the particles in its paths.
Answer» (a) Sublimation (b) Diffusion (c ) Dissolution/diffusion (d) Centrifugation (e ) Sedimentation.

Discussion

15.	Suppose you want to convert a gas into a liquid. Which two methods can you apply ?
Answer» (i) By increasing the pressure or by compressing the gas. (ii) By lowering the temperature or by cooling the gas.

Discussion

16.	Does the evaporation of a liquid occur only at a fixed temperature ?
Answer» No, the evaporation of a liquid occurs at all temperatures.

Discussion

17.	The boiling point of alcohol is `78^(@)C`. What is this temperature on Kelvin scale ?
Answer» Temperature on kelvin scale =78+273=351 K

Discussion

18.	What temperature in Kelvin scale is equale to `50^(@)C` ?
Answer» `50^(@)C=50+273=323 K`

Discussion

19.	Represent freezing and boiling temperature of water in Celsius as well as in Kelvin scales.
Answer» Freezing point temperature of water : `0^(@)C` or 273 K Boiling point temperature of water : `100^(@)C` or 373 K.

Discussion

20.	Name SI unit of measuring temperature. The boiling point of water is `100^(@)C` under normal atmospheric pressure. Convert this temperature of SI Units.
Answer» SI units of temperature to SI Units. `100^(@)C=(100+273)=373 K`

Discussion

21.	What is a pure substance ? Give its one characteristic.
Answer» A pure substance is the one which cannot be separated into smaller parts by any physical methods. It may be either a pure element (e.g. sodium) or a pure compound (e.g. calcium carbonate).

Discussion

22.	Define gaseous state of a substance.
Answer» A substance is said to be in the gaseous state if under normal pressure, its boiling point is below the room temperature. In other words, at room temperature the substance is in the gaseous state.

Discussion

23.	A substance upon heating directly changes into gaseous state. What is this change called ?
Answer» It is known as sublimation.

Discussion

24.	Which of the following energy is absorbed during the change of state of a substance ?A. specific heatB. latent heatC. heat capacityD. heat of solution
Answer» Correct Answer - B

Discussion

25.	On converting 308 K, 329 K and 391 K to Celsius scale, the correct sequence of temperature will be :A. `33^(@)C, 56^(@)C` and `118^(@)C`B. `35^(@)C, 56^(@)C` and `119^(@)C`C. `35^(@)C`, `56^(@)C` and `118^(@)C`D. `56^(@)C, 119^(@)C` and `35^(@)C`
Answer» Correct Answer - C

Discussion

26.	The evaporation of water increases under the following conditions :A. increase in temperature, decrease in surface areaB. increase in surface area, decrease in temperatureC. increase in surface area, rise in temperatureD. increase in temperature, increase in surface area, addition of common salt
Answer» Correct Answer - C

Discussion

27.	Which of the following statements is (are) incorrect ?A. Matter is made up of discret particles.B. The particles of matter always move along straight paths .C. At room temperature , the rate of evaporation of alchol is greater than that of ether .D. Fluidity of a liquid is its tendency to spread .
Answer» Correct Answer - B::C

Discussion

28.	The conversion of a solid into vapours without passing through the liquid state is called :A. vaporisationB. fusionC. sublimationD. freezing
Answer» Correct Answer - C

Discussion

29.	Which of the following statement is incorrect ?A. the particles of matter are very, very smallB. the particles of matter attract one anotherC. the particles of some of the matter are moving constantlyD. the particles of all the matter have spaces between them
Answer» Correct Answer - C

Discussion

30.	Which one of the following statement is not true ?A. the molecules in a solid vibrate about a fixed positionB. the molecules in a liquid are arranged in a regular patternC. the molecules in a gas exert negligibly small forces on each other, except during collisionsD. the molecules of a gas occupy all the space available
Answer» Correct Answer - B

Discussion

31.	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 observations is incorrect ?A. bromine vapour is made of tiny particles which are movingB. air is made up of tiny particles which are movingC. the particles of bromine are moving but those of air are not movingD. even though bromine vapour is heavier than air, it can move up against gravity
Answer» Correct Answer - C

Discussion

32.	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 bromineB. both air an bromine have the same densityC. bromine is heavier than airD. bromine cannot be heavier than air because it is going upwards against gravity
Answer» Correct Answer - C

Discussion

33.	You are provided with a fine white coloured powder which is either sugar or salt. How would you identify it without testing?
Answer» We can identify them by taste only. Sugar tastes sweet whereas common salt as we all know, has a bitter taste.

Discussion

34.	Why do we sweat more in a humid day ?
Answer» In a humid day, the air around us has already high percentage of water vapours. Therefore, the water coming from the skin gets less opportunity to change into vapours and remains sticking to our body. We therefore, sweat more on a humid day.

Discussion

35.	One of the following does not undergo sublimation. This one is :A. iodineB. sodium chlorideC. ammonium chlorideD. camphor
Answer» Correct Answer - B

Discussion

36.	How does pressure help in the liquefication of a gas ?
Answer» Increase in pressure helps in the liquefication of a gas. The particles or moelcules of a gas come closer and closer as the pressure is being increased gradually. They ultimately condense and as a result, the gas liquefies or changes into the liquid state.

Discussion

37.	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» Correct Answer - C

Discussion

38.	Which one of the following sets of phenomena would increase on raising the temperature ?A. Diffusion, evaporation, compression of gasesB. Evaporation, compression of gases, solubilityC. Evaporation, diffusion, expansion of gasesD. Evaporation, solubility, diffusion, compression of gases.
Answer» Correct Answer - C All the three phenomenon would increase upon increasing the temperature.

Discussion

39.	Which one of the following set of phenomena would increase on raising the temperature ?A. diffusion, evaporation, compression of gasesB. evaporation, compression of gases, solubilityC. evaporation, diffusion, expansion of gasesD. evaporation, solubility, diffusion, compression of gases
Answer» Correct Answer - C

Discussion

40.	The latent heat of fusion of ice is :A. `33.4 xx 10^(5) J//kg`B. `22.5 xx 10^(5) J//kg`C. `33.4 xx 10^(4) J//kg`D. `2.25 xx 10^(4) J//kg`
Answer» Correct Answer - C

Discussion

41.	The boiling point of ethane is, `- 88^(@)C`. This temperature will be equivalent to :A. 285 KB. 288 KC. 185 KD. 361 K
Answer» Correct Answer - C

Discussion

42.	You are provided with a mixture of naphthalene and ammonium chloride by your teacher. Suggest an activity to separate them with labelled diagram.
Answer» Both naphthalene and ammonium chloride sublime upon heating. Therefore, sublimation technique cannot be used to affect the separation. The separation can be done by dissolving the mixture in completely dry or anhydrous ether taken in a tube. Naphthalene being an organic substance, dissolves in ether whereas ammonium chloride does not dissolve as it is of inorganic nature. The solution formed is immediately filtered . Ammonium chloride is left on the filter paper as residue. It is dried and coolected. The filtrate is transferred to a china dish and kept in the atmosphere for sometime. Ether readily evaporates as it is a low boiling liquid. The white residue left in the dish is naphthalene. It can be removed and dried.

Discussion

43.	Tarun got an invitation to attend a patty. On coming to his place, he found that both his shirt and pent were wet. What step he would take to dry them quickly ?
Answer» The wet clothes can be dried in a number of ways. (i) By spreading them in air under sun so that the water may evaporate. (ii) By spreading them under a fan in a room. (iii) By ironing the clothes. As a result, the moisture present will escape as steam / vapours and the clothes will soon become dry.

Discussion

44.	Explain why, we can easily move our hand in air but to do the same through a plank of wood, we need a karate expert.
Answer» In air, the interparticle spaces are very large in number and the interparticle forces are quite weak. These can be easily overcome. That is why our hand can move in air. These spaces help in moving our hand in air, But in a solid block, the constituent particles are quite close and the interparticle forces are very strong. In case, one has to move his hand through a solid, it will be extremely difficult. Only a karate expert may do so.

Discussion

45.	Why should we call a wooden table a solid ?
Answer» A wooden table should be called a solid because it matches the characteristics of the solid state. For example, (i) It is very hard and rigid. (ii) Its shape cannot be changed by altering temperature or pressure. (iii) It is quite heavy which means high density. (iv) There is no movement of the constituent particles present.

Discussion

46.	A gas exerts pressure on the wall of the container. Assign reason.
Answer» The molecules in a gas have large kinetic energy. They strike the walls of the container with certain force and impart momentum to them. The force per unit area or momentum is responsible for the pressure of the gas.

Discussion

47.	Does the temperature of liquid increase further when it starts boiling ?
Answer» No, it does not because the energy now supplied is used up as latent heat of vaporisation only.

Discussion

48.	The conversion of a gas into liquid is calledA. gasificationB. sublimationC. condensationD. freezing
Answer» Correct Answer - C

Discussion

49.	As the presure of air decreases, the boiling point of a liquidA. increasesB. decreasesC. remains fixedD. none of these
Answer» Correct Answer - B

Discussion

50.	Which condition out of the following will increase the evaporation of water ?A. Increase in temperature of waterB. Decrease in temperature of waterC. Less exposed surface area of waterD. Adding common salt to water.
Answer» Correct Answer - A Increase in temperature always helps in evaporation of a liquid.

Discussion

Explore topic-wise InterviewSolutions in .

`25^(@)C` temperature is equal toA. `298.15K`B. `25K`C. `77^(@)F`D. `300K`

Give reason for the following observations. (a) Naphthalene balls disappear with time without leaving any solid. (b) We can get the smell of perfume sitting several metres away.

Why are gases highly compressible ?

Name the state of matter that : (i) has definite mass, volume and shape. (ii) has no definite volume and shape (iii) has minimum inter particle attraction. (iv) has maximum inter particle attraction.

Why are gases highly compressible while solids are almost incompressible ?

Melting points of three solids X, Y and Z are 298 K, 314K and 398 K respectively. Arrange these in increasing order of inter particle forces of attraction.

A cooler is quite effective on a hot and dry day. Explain.

Give reasons for the following observations : The smell of hot sizziling food reaches you several metres away but to get the smell from cold food, you have to go close.

Can we regard high fever as matter ?

Why do not solids possess fluidity ?

Dry ice isA. solid carbon dioxide .B. solid carbon monoxideC. liquid ammoniaD. ordinary ice

Suppose you want to convert a gas into a liquid. Which two methods can you apply ?

Does the evaporation of a liquid occur only at a fixed temperature ?

The boiling point of alcohol is `78^(@)C`. What is this temperature on Kelvin scale ?

What temperature in Kelvin scale is equale to `50^(@)C` ?

Represent freezing and boiling temperature of water in Celsius as well as in Kelvin scales.

Name SI unit of measuring temperature. The boiling point of water is `100^(@)C` under normal atmospheric pressure. Convert this temperature of SI Units.

What is a pure substance ? Give its one characteristic.

Define gaseous state of a substance.

A substance upon heating directly changes into gaseous state. What is this change called ?

Which of the following energy is absorbed during the change of state of a substance ?A. specific heatB. latent heatC. heat capacityD. heat of solution

On converting 308 K, 329 K and 391 K to Celsius scale, the correct sequence of temperature will be :A. `33^(@)C, 56^(@)C` and `118^(@)C`B. `35^(@)C, 56^(@)C` and `119^(@)C`C. `35^(@)C`, `56^(@)C` and `118^(@)C`D. `56^(@)C, 119^(@)C` and `35^(@)C`

The evaporation of water increases under the following conditions :A. increase in temperature, decrease in surface areaB. increase in surface area, decrease in temperatureC. increase in surface area, rise in temperatureD. increase in temperature, increase in surface area, addition of common salt

Which of the following statements is (are) incorrect ?A. Matter is made up of discret particles.B. The particles of matter always move along straight paths .C. At room temperature , the rate of evaporation of alchol is greater than that of ether .D. Fluidity of a liquid is its tendency to spread .

The conversion of a solid into vapours without passing through the liquid state is called :A. vaporisationB. fusionC. sublimationD. freezing

Which of the following statement is incorrect ?A. the particles of matter are very, very smallB. the particles of matter attract one anotherC. the particles of some of the matter are moving constantlyD. the particles of all the matter have spaces between them

You are provided with a fine white coloured powder which is either sugar or salt. How would you identify it without testing?

Why do we sweat more in a humid day ?

One of the following does not undergo sublimation. This one is :A. iodineB. sodium chlorideC. ammonium chlorideD. camphor

How does pressure help in the liquefication of a gas ?

Which one of the following sets of phenomena would increase on raising the temperature ?A. Diffusion, evaporation, compression of gasesB. Evaporation, compression of gases, solubilityC. Evaporation, diffusion, expansion of gasesD. Evaporation, solubility, diffusion, compression of gases.

Which one of the following set of phenomena would increase on raising the temperature ?A. diffusion, evaporation, compression of gasesB. evaporation, compression of gases, solubilityC. evaporation, diffusion, expansion of gasesD. evaporation, solubility, diffusion, compression of gases

The latent heat of fusion of ice is :A. `33.4 xx 10^(5) J//kg`B. `22.5 xx 10^(5) J//kg`C. `33.4 xx 10^(4) J//kg`D. `2.25 xx 10^(4) J//kg`

The boiling point of ethane is, `- 88^(@)C`. This temperature will be equivalent to :A. 285 KB. 288 KC. 185 KD. 361 K

You are provided with a mixture of naphthalene and ammonium chloride by your teacher. Suggest an activity to separate them with labelled diagram.

Tarun got an invitation to attend a patty. On coming to his place, he found that both his shirt and pent were wet. What step he would take to dry them quickly ?

Explain why, we can easily move our hand in air but to do the same through a plank of wood, we need a karate expert.

Why should we call a wooden table a solid ?

A gas exerts pressure on the wall of the container. Assign reason.

Does the temperature of liquid increase further when it starts boiling ?

The conversion of a gas into liquid is calledA. gasificationB. sublimationC. condensationD. freezing

As the presure of air decreases, the boiling point of a liquidA. increasesB. decreasesC. remains fixedD. none of these

Which condition out of the following will increase the evaporation of water ?A. Increase in temperature of waterB. Decrease in temperature of waterC. Less exposed surface area of waterD. Adding common salt to water.