Matter In Our Surroundings - MCQ Test (22-11-2017)


30 Questions MCQ Test | Matter In Our Surroundings - MCQ Test (22-11-2017)


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This mock test of Matter In Our Surroundings - MCQ Test (22-11-2017) for Class 9 helps you for every Class 9 entrance exam. This contains 30 Multiple Choice Questions for Class 9 Matter In Our Surroundings - MCQ Test (22-11-2017) (mcq) to study with solutions a complete question bank. The solved questions answers in this Matter In Our Surroundings - MCQ Test (22-11-2017) quiz give you a good mix of easy questions and tough questions. Class 9 students definitely take this Matter In Our Surroundings - MCQ Test (22-11-2017) exercise for a better result in the exam. You can find other Matter In Our Surroundings - MCQ Test (22-11-2017) extra questions, long questions & short questions for Class 9 on EduRev as well by searching above.
QUESTION: 1

What is the physical state of water at 100oC?

Solution:

The boiling point of pure water is 100oC or 373 K (100oC = 273 + 100 = 373 K). Boiling is a bulk phenomenon. At this temperature, particles from the bulk of the liquid gain enough energy to change into the vapour state. Therefore, the physical state of water at 100oC is water vapour (gaseous state of matter).

QUESTION: 2

An Almirah is a solid because its

Solution:

An almirah is solid because it is hard and rigid, have fixed shape and have very high density. All these properties are possessed by solid substance only.

QUESTION: 3

Find the incorrect statement

Solution:

Cooling is not caused during boiling. The normal room temperature is 298K or.25C Evaporation is a surface phenomenon but boiling is a bulk phenomenon. The liquid having low boiling points evaporate faster.

QUESTION: 4

When acetone or nail polish remover is applied cooling is experienced due to which factor?

Solution:

Evaporation causes cooling effect because the heat of evaporation is absorbed by the surroundings. Evaporation of acetone present in nail polish remover absorbs the latent heat from the nail Causing cooling of a  nail.

QUESTION: 5

Convert 300 K into Celsius.

Solution:

Kelvin is the SI unit of temperature. To change a temperature on the Kelvin scale to the Celsius scale, 273 has to be subtracted from the given temperature. To convert a temperature on the Celsius scale to the Kelvin scale, 273 has to be added to the given temperature. 

Temperature on Celsius scale = Temperature on Kelvin scale - 273

C = K−273 = 27C

QUESTION: 6

Arrange the following substances in increasing order of attraction between the particles: water, sugar, oxygen.

Solution:

Particles of solids ( sugar) have the very high force of attraction, particles of liquid (water) have less force of attraction than solids and particles of gases ( oxygen) have very less force of attraction. So correct order of increasing attraction between particles is Oxygen, water and sugar.

QUESTION: 7

The melting point of a substance is defined as the constant temperature at Atmospheric pressure when

Solution:

The constant temperature at which solid start changing into liquid at atmospheric temperature is called melting point. At this temperature, both the solid and liquid exist together.

QUESTION: 8

Identify the incorrect statement about evaporation
(A) It causes cooling
(B) It increase with increase in humidity
(C) It decreases with increase in temperature
(D) It increases with increase in wind speed

Solution:

The rate of evaporation increases with increase in temperature, surface area & wind speed but decrease by the increase in humidity.

QUESTION: 9

According to ancient philosophers matter consists of

Solution:

According to ancient philosophers matter consists of five constituents (panchtatva). They are air, earth, fire, sky and water.

QUESTION: 10

The inter-particle forces are the strongest in

Solution:

Solids substances have the strongest inter-particle force of attraction. In the given substances, sodium bromide is solid, ethyl alcohol is liquid and ammonia and carbon dioxide are gases. So, the particles of Sodium bromide have the strongest force of attraction.

QUESTION: 11

Which one of the following decreases the extent of evaporation of water?

Solution:

Evaporation of water increase with the increase in temperature, surface area and wind speed but decrease with increase in humidity. So, the larger humidity will decrease the rate of evaporation.

QUESTION: 12

Water kept in an earthen pot becomes cool in summer, because 
(A) Molecules of water escape through pores, and cause cooling 
(B) Earthen pots are made up of clay 
(C) It decreases the temperature of water 
(D) In summer, the rate of evaporation of water is faster. 

Solution:
QUESTION: 13

Name the state of matter that ‘has minimum inter-particle force of attraction’

Solution:

The particles of gases are away from each other. So, gas has the minimum inter-particle force of attraction.Solids have maximum force of attraction

QUESTION: 14

Pressure on the surface of a gas is increased. What will happen to the inter-particle forces?

Solution:

When the pressure on the surface of a gas is increased. The particles of gases comes closer that increase the inter-particle force of attraction.

QUESTION: 15

A desert cooler given comfort due to cooling caused by evaporation of water. Under which one of the following conditions it works more effectively?

Solution:

Desert cooler causes cooling effect due to evaporation of water as evaporation causes cooling effect. A desert cooler works more effectively when weather is hot and dry.

QUESTION: 16

The two major gases present in air are

Solution:

Air is a mixture of gases. Two main constituents of air is  Nitrogen (78%) and Oxygen (21%). Other gases include carbon dioxide, helium, water vapour etc.

QUESTION: 17

Identify the incorrect statement

Solution:

Ether and Acetone is most volatile. Alcohol is moderately volatile and water is least volatile. So, the statement, Acetone is least volatile is incorrect statement.

QUESTION: 18

Statement A : A substance is said to be in the liquid state if under normal pressure its M. P. is below the room temperature. 

Statement B : The melting point of solid and the freezing point of liquid is different. 

Which of the two statements is true?

Solution:

A substance is said to be in liquid state if under normal pressure its melting point is below the room temperature. Melting point of solid and the freezing point of liquid is same. So, statement A is correct but B is wrong.

QUESTION: 19

When alcohol is kept in a china dish it evaporates, temperature falls and cooling is produced. Which one is the correct method to record the temperature?

Solution:

By touching the surface of china dish. This is due to the fact that to change from liquid to the vapour state, alcohol requires latent heat of vaporisation. the alcohol takes this heat of vaporisation from china dish. The china dish loses heat and gets cooled.

QUESTION: 20

Three pieces of cloths were soaked in water, alcohol and ether separately and kept on a table. What is the decreasing order of drying of the cloths?

Solution:

The cloth soaked in water takes longer time in drying as it is less volatile. Cloth soaked in alcohol is will take less time than water and cloth soaked in ether will dry quickly as it is highly volatile. So, correct order is Water < Alcohol < Ether.

QUESTION: 21

Statement A: Celsius scale is the best scale for measuring temperature. 

Statement B: CO2 is heavier gas than both N2 and O2

Which of the two statements is true?

Solution:

Kelvin scale is used as standard unit of temperature. CO2 is heavier gas than N2 and O2.

QUESTION: 22

Find the incorrect statement

Solution:

Gases have maximum fluidity and least rigidity. The particle of solids have negligible kinetic energy. Inter-particle attraction depends on the physical state of the matter. Potassium permanganate is purple in colour.

QUESTION: 23

In an endothermic process heat is absorbed, in an exothermic process heat is evolved and in an athermic process no thermal change is observed. What is the nature of evaporation of ether?

Solution:

Evaporation of ether occurs due to absorption of heat by surrounding. So, it is an endothermic process.The chemical reaction in which heat is absorbed in called as an endothermic reaction. The reaction in which heat is evolved is called exothermic reaction and the reaction in which no thermal changes occur is called athermic process.

QUESTION: 24

Sulphur dioxide is collected in the lab in a gas jar by upward displacement of air. Which of the following statement is correct regarding the density of the gas?

Solution:

Sulphur dioxide gas is collected in the lab in a gas jar by upward displacement of the air because Sulphur dioxide gas is heavier than air. The gases lighter than air are collected by downward displacement of water.

QUESTION: 25

The room temperature on Celsius scale is25°C. What is the temperature on the Kelvin scale?

Solution:

K =C+273, 25C = 273+25=298K. So, temperature of 25°Cis equal to 298K.

QUESTION: 26

Which of the following statements is not true?

Solution:

Anything that occupies space and have mass is called matter. Inter-particle space is maximum in the gaseous state of substance. The particles constitute zig-zag path and solid is most compact state of substance. Matter is not always continuous in nature.

QUESTION: 27

Which of the two statement is true

Statement A : Petrol, ether, acetone, water, CCl4 are volatile liquid

Statement B : Naphthalene, Camphor, iodine, NH4Cl undergo sublimation.

Solution:

Naphthalene, camphor, iodine and ammonium chloride are sublime substance. So, statement B is correct. Petrol, ether, acetone and carbon tetrachloride are volatile liquid but water is not a volatile liquid.

QUESTION: 28

Which of the two statements is true?

Statement A: The temperature of the liquid becomes constant once it starts boiling.

Statement B: Pressure of air at sea level is 70 cm.

Solution:

Statement A is correct. The temperature of the liquid becomes constant once it starts boiling. The heat is used to change the state of matter.

The pressure of air at the sea level is 760 mm (76 cm) of Hg (mercury).

QUESTION: 29

Name one common substance which can undergo a change in state upon heating or cooling.

Solution:

Water can undergo a change in state upon heating and cooling. On heating above 100°C water change into a gaseous state and on cooling below 0°C it changes into the solid state.

QUESTION: 30

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

Solution:

The process of changing solids into gases without changing into liquid state or gases directly into solid is called sublimation.

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