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All questions of Composition of Matter for Class 8 Exam
What is the physical state of water at 100°C?- a)both gaseous and liquid state
- b)solid state
- c)liquid state
- d)gaseous state
Correct answer is option 'A'. Can you explain this answer?
What is the physical state of water at 100°C?
a)
both gaseous and liquid state
b)
solid state
c)
liquid state
d)
gaseous state
 | Arvind Singh answered |
At 100°C, water exists in both the liquid state as well as in gaseous state. This is special condition because 100°C is the boiling point of water and as well as liquefaction temperature of the water vapour
What is the physical state of water at100C?- a)Liquid
- b)Solid
- c)gas
- d)All of these
Correct answer is 'B'. Can you explain this answer?
What is the physical state of water at100C?
a)
Liquid
b)
Solid
c)
gas
d)
All of these
| | Arjun Sharma answered |
The answer is a .
The physical state of water at its boiling point temperature of 100 degree Celsius will be both liquid state as well as gaseous state. This is because at its boiling point of 100 degree celsius the liquid state of water starts changing into its Gaseous state (steam).
The change of state from solid to liquid known as –- a)Melting
- b)Boiling
- c)Sublimation
- d)None of these
Correct answer is option 'A'. Can you explain this answer?
The change of state from solid to liquid known as –
a)
Melting
b)
Boiling
c)
Sublimation
d)
None of these
| | Amit Sharma answered |
The change of state from solid to liquid is known as Melting. This is a process in which a solid substance changes into a liquid on heating. Heat energy is required to break the bonds between molecules, allowing them to move around freely. This process is also known as fusion, and the amount of energy required is called the latent heat of fusion. In a phase diagram such as Figure 12.4.1, the melting point is the temperature at which a substance can transition from a solid to a liquid.
Which substance undergo sublimation process –- a)Naphthalene
- b)Br2
- c)Ice
- d)N2
Correct answer is option 'A'. Can you explain this answer?
Which substance undergo sublimation process –
a)
Naphthalene
b)
Br
2c)
Ice
d)
N2
| | Sharad Chavan answered |
Naphthalene because it changes from solid to gaseous without undergoing liquid ...hence A is the correct answer
Under which of the following conditions we can boil water at room temperature?- a)At low pressure
- b)At moderate pressure
- c)At very high pressure
- d)At atmospheric pressure
Correct answer is option 'A'. Can you explain this answer?
Under which of the following conditions we can boil water at room temperature?
a)
At low pressure
b)
At moderate pressure
c)
At very high pressure
d)
At atmospheric pressure
 | Varun Kumar answered |
At low pressure
Explanation: Boiling occurs when the vapor pressure of a liquid equals the external pressure. At lower pressures, the boiling point of water decreases. So, if the external pressure is reduced significantly (below atmospheric pressure), water can boil at room temperature. This phenomenon can be observed in a vacuum chamber, where the pressure is significantly reduced, allowing water to boil at room temperature.
Explanation: Boiling occurs when the vapor pressure of a liquid equals the external pressure. At lower pressures, the boiling point of water decreases. So, if the external pressure is reduced significantly (below atmospheric pressure), water can boil at room temperature. This phenomenon can be observed in a vacuum chamber, where the pressure is significantly reduced, allowing water to boil at room temperature.
An Almirah is a solid because its- a)hard and rigid
- b)shape doesn’t change when pressed
- c)density is very high
- d)All of these
Correct answer is 'D'. Can you explain this answer?
An Almirah is a solid because its
a)
hard and rigid
b)
shape doesn’t change when pressed
c)
density is very high
d)
All of these
 | Jhanvi Mukherjee answered |
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.
The large volumes of gases can be put into small volumes of cylinders because of their property known as compressibility.- a)True
- b)False
Correct answer is 'A'. Can you explain this answer?
The large volumes of gases can be put into small volumes of cylinders because of their property known as compressibility.
a)
True
b)
False
 | Hansa Sharma answered |
The large volumes of gases can be put into small volumes of cylinders because of their property known as compressibility. This is possible because of the large inter particle distance and weak force of attraction between the particles of gas.
The boiling point of water on kelvin scale is –- a)573 K
- b)273 K
- c)373 K
- d)100 K
Correct answer is 'C'. Can you explain this answer?
The boiling point of water on kelvin scale is –
a)
573 K
b)
273 K
c)
373 K
d)
100 K
 | Om Menon answered |
Formula to change the value of celcious into kelvin is K=C+273 As we know that boiling point of water is 100 c. SO, K=100+273 K =373 k.
Gases have highest rate of diffusion among all the three states of matter.- a)True
- b)False
Correct answer is option 'A'. Can you explain this answer?
Gases have highest rate of diffusion among all the three states of matter.
a)
True
b)
False
| | Amit Kumar answered |
Diffusion is the property of matter which is based on the motion of its particles. Diffusion occurs in gases, liquids and solids. Diffusion is fastest in gases and slowest in solids. The rate of diffusion increases on increasing the temperature of the diffusing substance.
Can you explain the answer of this question below:Practice Test/Quiz or MCQ (Multiple Choice Questions) with Solutions of Chapter "Matter in our surroundings" are available for CBSE Class 9 Science and have been compiled as per the syllabus of CBSE Class 9 Science Q. Which of the following has the strongest interparticle force at the room temperature?- A:Nitrogen
- B:Mercury
- C:Iron
- D:Chalk
The answer is C.
Practice Test/Quiz or MCQ (Multiple Choice Questions) with Solutions of Chapter "Matter in our surroundings" are available for CBSE Class 9 Science and have been compiled as per the syllabus of CBSE Class 9 Science
Q. Which of the following has the strongest interparticle force at the room temperature?
A:
Nitrogen
B:
Mercury
C:
Iron
D:
Chalk
 | Sharanya shah answered |
Higher the melting point of a substance, greater will be the force of attraction between particles. The melting point of iron is considerably high, so the force of attraction between its particles is higher.
Convert the temperature of 373°C to the kelvin scale ?- a)646 K
- b)546 K
- c)300 K
- d)500 K
Correct answer is option 'A'. Can you explain this answer?
Convert the temperature of 373°C to the kelvin scale ?
a)
646 K
b)
546 K
c)
300 K
d)
500 K
 | Nikhil Mehra answered |
We know that ,K = °C + 273.15
= 373 deg C + 273.15 deg C
= 646.15 deg C
Water has boiling point equal to 100°C.- a)True
- b)False
Correct answer is option 'A'. Can you explain this answer?
Water has boiling point equal to 100°C.
a)
True
b)
False
 | Zzz answered |
It is true as boiling point of water is 100 degree Celsius, the statement is absolutely true and correct
Camphor changes to gaseous state without changing into liquid.- a)True
- b)False
Correct answer is option 'A'. Can you explain this answer?
Camphor changes to gaseous state without changing into liquid.
a)
True
b)
False
 | Jithin Das answered |
It's true because camphor is sublime and it changes directly into gas without passing through the state of liquid. The process in which solid directly changes into gas without passing through the state of liquid is called sublimation.
The process of change of a liquid into vapour at any temperature is called –- a)Diffusion
- b)Evaporation
- c)Cooling
- d)Heating
Correct answer is option 'B'. Can you explain this answer?
The process of change of a liquid into vapour at any temperature is called –
a)
Diffusion
b)
Evaporation
c)
Cooling
d)
Heating
 | Ravi Verma answered |
The process of conversion of a substance from the liquid state to its vapor state at any temperature below boiling point is called evaporation or vaporization.
Can you explain the answer of this question below:Evaporation causes heating
- A:
True
- B:
False
The answer is B.
Evaporation causes heating
True
False
| | Arjun Sharma answered |
When evaporation occurs then than the liquid (mostly water) absorbs all the heat from the surroundings and take it with it and we feel cool. evaporation causes cooling effect because the heat energy is abosorbed by surrounding particles.
Name the process by which a drop of ink spreads in a beaker of water –- a)Diffusion
- b)Vaporization
- c)Condensation
- d)Sublimation
Correct answer is option 'A'. Can you explain this answer?
Name the process by which a drop of ink spreads in a beaker of water –
a)
Diffusion
b)
Vaporization
c)
Condensation
d)
Sublimation
 | Hridoy Verma answered |
The process by which a drop of ink spreads in a beaker of water is called diffusion.
The temperature at which liquid starts boiling at atmospheric pressure known as –- a)Melting point
- b)Boiling point
- c)Latent heat
- d)Condensation
Correct answer is option 'B'. Can you explain this answer?
The temperature at which liquid starts boiling at atmospheric pressure known as –
a)
Melting point
b)
Boiling point
c)
Latent heat
d)
Condensation
| | Sarita Reddy answered |
Boiling occurs when the vapor pressure reaches or exceeds the surrounding pressure from the atmosphere or whatever else is in contact with the liquid. At standard atmospheric pressure (1 atmosphere = 0.101325 MPa), water boils at approximately 100 degrees Celsius.
Fluids are –- a)Liquids and gases
- b)Solids and gases
- c)Liquids and solids
- d)Only solids
Correct answer is option 'A'. Can you explain this answer?
Fluids are –
a)
Liquids and gases
b)
Solids and gases
c)
Liquids and solids
d)
Only solids
| | Arvind Singh answered |
In physics, a fluid is a substance that continually deforms under an applied shear stress. Fluids are a subset of the phases of matter and include liquids, gases, plasmas, and to some extent, plastic solids.
The process for the change of a solid directly into its vapour is called –- a)Evaporation
- b)Ebullition
- c)Condensation
- d)Sublimation
Correct answer is option 'D'. Can you explain this answer?
The process for the change of a solid directly into its vapour is called –
a)
Evaporation
b)
Ebullition
c)
Condensation
d)
Sublimation
 | Sanchita Choudhury answered |
Sublimation is the process through which the solid substance changes directly into vapours or gaseous state without passing through liquid state. Dry ice is a common example of this process.
Convert the temperature of 270 K to the celsius scale –- a)– 3°C
- b)– 4°C
- c)2°C
- d)5°C
Correct answer is option 'A'. Can you explain this answer?
Convert the temperature of 270 K to the celsius scale –
a)
– 3°C
b)
– 4°C
c)
2°C
d)
5°C
| | Amit Kumar answered |
We know that °C = K - 273.15
C= K - 273
C= 270 - 273
C = -3
C= 270 - 273
C = -3
Plasma is the.......... state of matter –- a)First
- b)Second
- c)Third
- d)Fourth
Correct answer is option 'D'. Can you explain this answer?
Plasma is the.......... state of matter –
a)
First
b)
Second
c)
Third
d)
Fourth
| | Ananya Sharma answered |
A plasma is a hot ionized gas consisting of approximately equal numbers of positively charged ions and negatively charged electrons. The characteristics of plasmas are significantly different from those of ordinary neutral gases so that plasmas are considered a distinct "fourth state of matter."
Find the incorrect statement- a)Low boiling liquids evaporate faster than high boiling liquids.
- b)Cooling is caused during boiling
- c)The normal room temperature is 298K and 293K both.
- d)Evaporation is a surface phenomenon but boiling is not
Correct answer is option 'B'. Can you explain this answer?
Find the incorrect statement
a)
Low boiling liquids evaporate faster than high boiling liquids.
b)
Cooling is caused during boiling
c)
The normal room temperature is 298K and 293K both.
d)
Evaporation is a surface phenomenon but boiling is not
| | Raghav Bansal answered |
The normal room temperature is 298K or 25∘C. Other common values are 293 K (20 C or 68 F). Evaporation is a surface phenomenon but boiling is bulk phenomenon. Liquid having low boiling points evaporate faster. Cooling is not caused during boiling.
The melting point of ice is –- a)0°C
- b)4°C
- c)5°C
- d)None of these
Correct answer is option 'A'. Can you explain this answer?
The melting point of ice is –
a)
0°C
b)
4°C
c)
5°C
d)
None of these
 | Geetika Shah answered |
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. For ice, the melting point is 0°C at which ice a solid turn to water.
Dry ice is –- a)Water in solid state
- b)Water in gaseous state
- c)CO2 in liquid state
- d)CO2 in solid state
Correct answer is option 'D'. Can you explain this answer?
Dry ice is –
a)
Water in solid state
b)
Water in gaseous state
c)
CO2 in liquid state
d)
CO2 in solid state
| | Ananya Sharma answered |
Dry ice, sometimes referred to as "cardice", is the solid form of carbon dioxide. It is used primarily as a cooling agent. Its advantages include lower temperature than that of water ice and not leaving any residue.
Match the following with correct response.
(1) Sublimation
(2) Evaporation
(3) Latent heat of vaporization
(4) Latent heat of fusion
(A) Heat required to change the state of 1Kg of solid into liquid
(B) Change of liquid state into vapours without coming to its boiling point
(C) Change of solid directly into vapours
(D) Heat required to change the state of 1Kg liquid into vapours- a)1-D, 2-A, 3-C, 4-B
- b)1-A, 2-C, 3-B, 4-D
- c)1-B, 2-D, 3-A, 4-C
- d)1-C, 2-B, 3-D, 4-A
Correct answer is option 'D'. Can you explain this answer?
Match the following with correct response.
(1) Sublimation
(2) Evaporation
(3) Latent heat of vaporization
(4) Latent heat of fusion
(A) Heat required to change the state of 1Kg of solid into liquid
(B) Change of liquid state into vapours without coming to its boiling point
(C) Change of solid directly into vapours
(D) Heat required to change the state of 1Kg liquid into vapours
(1) Sublimation
(2) Evaporation
(3) Latent heat of vaporization
(4) Latent heat of fusion
(A) Heat required to change the state of 1Kg of solid into liquid
(B) Change of liquid state into vapours without coming to its boiling point
(C) Change of solid directly into vapours
(D) Heat required to change the state of 1Kg liquid into vapours
a)
1-D, 2-A, 3-C, 4-B
b)
1-A, 2-C, 3-B, 4-D
c)
1-B, 2-D, 3-A, 4-C
d)
1-C, 2-B, 3-D, 4-A
 | Pooja Shah answered |
The change of solid directly into vapours is called Sublimation. The change of liquid state into vapours without coming to it's boiling point is called Evaporation. The latent heat of Vaporization is the heat required to change the state of 1 kg into vapours. Latent heat of fusion is the heat required to Change the state of 1 kg of solid into liquid.
Arrange the following substances in increasing order of attraction between the particles: water, sugar, oxygen.- a)water < sugar < oxygen
- b)oxygen < water < sugar
- c)sugar < oxygen < water
- d)none
Correct answer is option 'B'. Can you explain this answer?
Arrange the following substances in increasing order of attraction between the particles: water, sugar, oxygen.
a)
water < sugar < oxygen
b)
oxygen < water < sugar
c)
sugar < oxygen < water
d)
none
| | Ravi Verma answered |
Sugar is a solid; the forces of attraction between the particles of sugar are strong. Water is a liquid; the forces of attraction here are weaker than sugar. Oxygen is a gas; the forces of attraction are the weakest in gases.
Thus, the increasing order of forces of attraction between the particles of water, sugar and oxygen is
Oxygen < Water < Sugar
The physical state of matter which can be easily compressed –- a)Liquid
- b)Gas
- c)Solid
- d)None of these
Correct answer is 'B'. Can you explain this answer?
The physical state of matter which can be easily compressed –
a)
Liquid
b)
Gas
c)
Solid
d)
None of these
 | Jyoti Kapoor answered |
The physical state of matter which can be easily compressed is the gaseous state as thy have more interparticular space and the particles present in them have very little force of attraction. So they can be easily compressed in contrast to solid and liquid.
Condensing is opposite to evaporating and freezing is opposite to melting.- a)True
- b)False
Correct answer is option 'A'. Can you explain this answer?
Condensing is opposite to evaporating and freezing is opposite to melting.
a)
True
b)
False
 | Tanishq Patel answered |
Explanation:
Condensing and Evaporating:
- Condensing is the process by which a substance changes from a gas to a liquid state, usually by cooling. This occurs when the particles of the gas slow down and come together to form a liquid.
- Evaporating, on the other hand, is the process by which a substance changes from a liquid to a gas state, usually by heating. This occurs when the particles of the liquid gain enough energy to break free and become a gas.
Opposites:
- Condensing and evaporating are indeed opposite processes. When a substance condenses, it goes from a gas to a liquid state, whereas when it evaporates, it goes from a liquid to a gas state. These processes are reverse of each other and involve opposite changes in the state of matter.
Freezing and Melting:
- Freezing is the process by which a substance changes from a liquid to a solid state, usually by cooling. This occurs when the particles of the liquid slow down and come together to form a solid.
- Melting, on the other hand, is the process by which a substance changes from a solid to a liquid state, usually by heating. This occurs when the particles of the solid gain enough energy to break free and become a liquid.
Opposites:
- Freezing and melting are indeed opposite processes. When a substance freezes, it goes from a liquid to a solid state, whereas when it melts, it goes from a solid to a liquid state. These processes are reverse of each other and involve opposite changes in the state of matter.
Condensing and Evaporating:
- Condensing is the process by which a substance changes from a gas to a liquid state, usually by cooling. This occurs when the particles of the gas slow down and come together to form a liquid.
- Evaporating, on the other hand, is the process by which a substance changes from a liquid to a gas state, usually by heating. This occurs when the particles of the liquid gain enough energy to break free and become a gas.
Opposites:
- Condensing and evaporating are indeed opposite processes. When a substance condenses, it goes from a gas to a liquid state, whereas when it evaporates, it goes from a liquid to a gas state. These processes are reverse of each other and involve opposite changes in the state of matter.
Freezing and Melting:
- Freezing is the process by which a substance changes from a liquid to a solid state, usually by cooling. This occurs when the particles of the liquid slow down and come together to form a solid.
- Melting, on the other hand, is the process by which a substance changes from a solid to a liquid state, usually by heating. This occurs when the particles of the solid gain enough energy to break free and become a liquid.
Opposites:
- Freezing and melting are indeed opposite processes. When a substance freezes, it goes from a liquid to a solid state, whereas when it melts, it goes from a solid to a liquid state. These processes are reverse of each other and involve opposite changes in the state of matter.
Which of the following does not affect rate of evaporation?- a)Wind speed
- b)Surface area
- c)Temperature
- d)Insoluble heavy impurities
Correct answer is option 'D'. Can you explain this answer?
Which of the following does not affect rate of evaporation?
a)
Wind speed
b)
Surface area
c)
Temperature
d)
Insoluble heavy impurities
 | Subham Gupta answered |
Factors Affecting Rate of Evaporation
• Wind Speed: Higher wind speeds can increase the rate of evaporation by carrying away the water vapor molecules from the surface, creating a lower concentration of water vapor around the liquid. This allows more water molecules to evaporate.
• Surface Area: A larger surface area can increase the rate of evaporation as more liquid molecules are exposed to the air, allowing for more evaporation to occur.
• Temperature: Higher temperatures can increase the rate of evaporation as the kinetic energy of the liquid molecules increases, leading to more molecules escaping into the air.
• Insoluble Heavy Impurities: Insoluble heavy impurities do not affect the rate of evaporation. These impurities remain in the liquid and do not impact the evaporation process. The rate of evaporation is primarily influenced by factors such as wind speed, surface area, and temperature.
• Wind Speed: Higher wind speeds can increase the rate of evaporation by carrying away the water vapor molecules from the surface, creating a lower concentration of water vapor around the liquid. This allows more water molecules to evaporate.
• Surface Area: A larger surface area can increase the rate of evaporation as more liquid molecules are exposed to the air, allowing for more evaporation to occur.
• Temperature: Higher temperatures can increase the rate of evaporation as the kinetic energy of the liquid molecules increases, leading to more molecules escaping into the air.
• Insoluble Heavy Impurities: Insoluble heavy impurities do not affect the rate of evaporation. These impurities remain in the liquid and do not impact the evaporation process. The rate of evaporation is primarily influenced by factors such as wind speed, surface area, and temperature.
Condensation process is –- a)Change of state from gas to liquid
- b)Change of state from liquid to gas
- c)Change of state from gas to solid
- d)Change of state from solid to liquid
Correct answer is option 'A'. Can you explain this answer?
Condensation process is –
a)
Change of state from gas to liquid
b)
Change of state from liquid to gas
c)
Change of state from gas to solid
d)
Change of state from solid to liquid
| | Sharad Chavan answered |
The process of changing from gaseous state to liquid state on cooling is called condensation.
What is volume of gases?- a)Definite
- b)Almost Nil
- c)Large
- d)Take the volume of container
Correct answer is option 'D'. Can you explain this answer?
What is volume of gases?
a)
Definite
b)
Almost Nil
c)
Large
d)
Take the volume of container
| | Jyoti Kapoor answered |
A gas is a substance with no definite volume and no definite shape. Solids and liquids have volumes that do not change easily. A gas, on the other hand, has a vol- ume that changes to match the volume of its container. The molecules in a gas are very far apart compared with the molecules in a solid or a liquid.
Which of the following is not correct? - a)SI unit of temperature is kelvin
- b)SI unit of pressure is Newton
- c)SI unit of density is kg/m3
- d)1 litre = 1000 cm3 - 1 dm3
Correct answer is option 'B'. Can you explain this answer?
Which of the following is not correct?
a)
SI unit of temperature is kelvin
b)
SI unit of pressure is Newton
c)
SI unit of density is kg/m3
d)
1 litre = 1000 cm3 - 1 dm3
| | Kritika Bose answered |
SI Units of Measurement
SI units are the International System of Units, which is the modern form of the metric system. It is used in scientific and technical fields as a standard system of measurement. The SI system has seven base units, which are used to derive all other units of measurement.
SI Units of Temperature, Pressure, Density and Volume
Temperature: The SI unit of temperature is Kelvin (K), not Celsius (°C).
Pressure: The SI unit of pressure is Pascal (Pa), not atm (atmosphere).
Density: The SI unit of density is kilograms per cubic meter (kg/m3).
Volume: The SI unit of volume is cubic meter (m3). However, liter (L) is also commonly used as a non-SI unit of volume. 1 L = 1000 cm3 = 1 dm3.
Conclusion
Option B is not correct because the SI unit of pressure is Pascal (Pa), not atm (atmosphere). Atm is a non-SI unit of pressure. Therefore, the correct answer is option B.
SI units are the International System of Units, which is the modern form of the metric system. It is used in scientific and technical fields as a standard system of measurement. The SI system has seven base units, which are used to derive all other units of measurement.
SI Units of Temperature, Pressure, Density and Volume
Temperature: The SI unit of temperature is Kelvin (K), not Celsius (°C).
Pressure: The SI unit of pressure is Pascal (Pa), not atm (atmosphere).
Density: The SI unit of density is kilograms per cubic meter (kg/m3).
Volume: The SI unit of volume is cubic meter (m3). However, liter (L) is also commonly used as a non-SI unit of volume. 1 L = 1000 cm3 = 1 dm3.
Conclusion
Option B is not correct because the SI unit of pressure is Pascal (Pa), not atm (atmosphere). Atm is a non-SI unit of pressure. Therefore, the correct answer is option B.
Intermolecular forces are maximum in solids and minimum in gases.- a)True
- b)False
Correct answer is option 'A'. Can you explain this answer?
Intermolecular forces are maximum in solids and minimum in gases.
a)
True
b)
False
 | Arjun Desai answered |
Intermolecular force refers to the force that exists between two or more molecules.
Intermolecular force of attraction is maximum in solids.
This is because molecules in solid remain very close to each other which allot a definite shape to the objects that are solid.
It is lesser in liquids and least in the gases.
Kinetic energy of molecules is directly proportional to - a)Temperature
- b)Pressure
- c)Both (a) and (b)
- d)Atmospheric pressure
Correct answer is option 'A'. Can you explain this answer?
Kinetic energy of molecules is directly proportional to
a)
Temperature
b)
Pressure
c)
Both (a) and (b)
d)
Atmospheric pressure
 | Ishan Yadav answered |
The kinetic energy of molecules
K=3/2 kB. T
K = average kinetic energy per molecule of gas (J)
kB = Boltzmann's constant ()
T = temperature (k)
K=3/2 kB. T
K = average kinetic energy per molecule of gas (J)
kB = Boltzmann's constant ()
T = temperature (k)
Which of the following statements is incorrect?- a)Matter is made up of particles
- b)Particles of matter are always in state of motion
- c)Matter is continuous in nature
- d)Particles of matter attract each other
Correct answer is option 'C'. Can you explain this answer?
Which of the following statements is incorrect?
a)
Matter is made up of particles
b)
Particles of matter are always in state of motion
c)
Matter is continuous in nature
d)
Particles of matter attract each other
| | Bhaskar Chatterjee answered |
Incorrect Statement: Matter is continuous in nature.
Explanation:
Matter is made up of small particles called atoms and molecules that have mass and occupy space. These particles are not continuous but are separated by empty spaces. Therefore, the statement that "matter is continuous in nature" is incorrect.
Evidence Supporting the Correct Statements:
a) Matter is made up of particles:
The concept of matter being made up of small particles was first proposed by the Greek philosopher Democritus in the 5th century BC. This idea was later supported by scientists like John Dalton, who proposed the atomic theory of matter in the 19th century. Today, we know that matter is made up of atoms and molecules.
b) Particles of matter are always in a state of motion:
Particles of matter are always in motion, even when they appear to be at rest. This motion can be either random or organized. The kinetic theory of matter explains that the temperature of matter is related to the speed of its particles. When matter is heated, the particles move faster and vice versa.
d) Particles of matter attract each other:
Particles of matter attract each other due to the presence of forces like gravitational, electric, and magnetic forces. These forces allow particles to stick together and form larger structures like molecules, crystals, and even planets.
Conclusion:
In conclusion, the statement that "matter is continuous in nature" is incorrect. Matter is made up of small particles that are separated by empty spaces. These particles are always in motion and attract each other due to the presence of forces.
Explanation:
Matter is made up of small particles called atoms and molecules that have mass and occupy space. These particles are not continuous but are separated by empty spaces. Therefore, the statement that "matter is continuous in nature" is incorrect.
Evidence Supporting the Correct Statements:
a) Matter is made up of particles:
The concept of matter being made up of small particles was first proposed by the Greek philosopher Democritus in the 5th century BC. This idea was later supported by scientists like John Dalton, who proposed the atomic theory of matter in the 19th century. Today, we know that matter is made up of atoms and molecules.
b) Particles of matter are always in a state of motion:
Particles of matter are always in motion, even when they appear to be at rest. This motion can be either random or organized. The kinetic theory of matter explains that the temperature of matter is related to the speed of its particles. When matter is heated, the particles move faster and vice versa.
d) Particles of matter attract each other:
Particles of matter attract each other due to the presence of forces like gravitational, electric, and magnetic forces. These forces allow particles to stick together and form larger structures like molecules, crystals, and even planets.
Conclusion:
In conclusion, the statement that "matter is continuous in nature" is incorrect. Matter is made up of small particles that are separated by empty spaces. These particles are always in motion and attract each other due to the presence of forces.
Assertion (A): Water droplets form on the outer surface of a glass containing ice-cold water.
Reason (R): Water evaporates from the glass and condenses on the outside.- a)If both Assertion and Reason are true and Reason is the correct explanation of Assertion
- b)If both Assertion and Reason are true but Reason is not the correct explanation of Assertion
- c)If Assertion is true but Reason is false
- d)If both Assertion and Reason are false
Correct answer is option 'C'. Can you explain this answer?
Assertion (A): Water droplets form on the outer surface of a glass containing ice-cold water.
Reason (R): Water evaporates from the glass and condenses on the outside.
Reason (R): Water evaporates from the glass and condenses on the outside.
a)
If both Assertion and Reason are true and Reason is the correct explanation of Assertion
b)
If both Assertion and Reason are true but Reason is not the correct explanation of Assertion
c)
If Assertion is true but Reason is false
d)
If both Assertion and Reason are false
 | Elite Coaching Classes answered |
- Assertion (A) is true: Water droplets form on the outer surface of a glass containing ice-cold water because the cold temperature of the glass causes moisture in the air to condense.
- Reason (R) is false: Water does not evaporate from the glass and condense on the outside. Instead, the moisture in the surrounding air condenses on the cooler surface of the glass.
- Therefore, the correct option is C: The assertion is true, but the reason is false.
- Reason (R) is false: Water does not evaporate from the glass and condense on the outside. Instead, the moisture in the surrounding air condenses on the cooler surface of the glass.
- Therefore, the correct option is C: The assertion is true, but the reason is false.
What is the physical state of water at 1000C?- a)gaseous
- b)Solid
- c)Liquid
- d)All of these
Correct answer is option 'A'. Can you explain this answer?
What is the physical state of water at 1000C?
a)
gaseous
b)
Solid
c)
Liquid
d)
All of these
| | Raghav Bansal answered |
The boiling point of water is 100°C. The physical state of water at its boiling point temperature of 100 degree Celsius will be both liquid state as well as gaseous state.
Solids do not flow because - a)of large molecular space between particles
- b)they do not have definite shape
- c)they have very strong intermolecular forces in between particles
- d)all of these
Correct answer is option 'C'. Can you explain this answer?
Solids do not flow because
a)
of large molecular space between particles
b)
they do not have definite shape
c)
they have very strong intermolecular forces in between particles
d)
all of these
 | Moumita Mishra answered |
Any thing flows due to weaker intermolecular forces between them.
Which of the following is correct order of forces of attraction?- a)Water > Air > Sand
- b)Air > Sugar > Oil
- c)Air < Water < Sugar
- d)Salt > Air > Juice
Correct answer is option 'C'. Can you explain this answer?
Which of the following is correct order of forces of attraction?
a)
Water > Air > Sand
b)
Air > Sugar > Oil
c)
Air < Water < Sugar
d)
Salt > Air > Juice
| | Ujwal Das answered |
B) Water is attracted to nonpolar substances, then polar substances, and finally to itself through hydrogen bonding.
Which factor affecting Evaporation - - a)Temperature
- b)Surface area
- c)Both (A) & (B)
- d)None of these
Correct answer is option 'C'. Can you explain this answer?
Which factor affecting Evaporation -
a)
Temperature
b)
Surface area
c)
Both (A) & (B)
d)
None of these
 | Tushar Mehta answered |
The turning of any liquid into vapour is called Evaporation. The factors affecting the evaporation are:
1. Temperature. As the temperature increases, the rate of evaporation also increases.
2. Surface Area. As the Surface area increases, the rate of evaporation increases.
3. Density. As the density increases, the rate of evaporation decreases.
4. Wind Velocity. The velocity of the wind also affects the rate of evaporation. As the velocity of wind increases, the rate of evaporation increases.
Which one of the following sets of phenomenon would increase on raising the temperature?- a)Evaporation, diffusion, compression of gases
- b)Evaporation, compression of gases, solubility
- c)Evaporation, diffusion, expansion of gases
- d)Evaporation, solubility, diffusion, compression of gases.
Correct answer is option 'C'. Can you explain this answer?
Which one of the following sets of phenomenon would increase on raising the temperature?
a)
Evaporation, diffusion, compression of gases
b)
Evaporation, compression of gases, solubility
c)
Evaporation, diffusion, expansion of gases
d)
Evaporation, solubility, diffusion, compression of gases.
 | Mihir Shah answered |
The correct answer is option 'C': Evaporation, diffusion, expansion of gases.
Explanation:
When the temperature is increased, several physical processes tend to increase. These processes include evaporation, diffusion, and expansion of gases. Let's understand each of these phenomena in detail:
1. Evaporation:
Evaporation is the process by which a liquid changes into a vapor or gas at temperatures below its boiling point. When the temperature is increased, the kinetic energy of the molecules in the liquid also increases. As a result, more molecules gain enough energy to overcome the attractive forces of the liquid and escape into the gas phase. Therefore, evaporation increases with an increase in temperature.
2. Diffusion:
Diffusion is the process of movement of particles from an area of higher concentration to an area of lower concentration. It occurs due to the random motion of particles. When the temperature is increased, the kinetic energy of the particles also increases. This increased kinetic energy leads to faster and more frequent collisions between particles, resulting in an increased rate of diffusion.
3. Expansion of gases:
When gases are heated, their molecules gain kinetic energy and move faster. This increased molecular motion leads to an increase in the volume of the gas because the molecules now occupy a larger space. Therefore, gases expand when the temperature is raised.
These three phenomena - evaporation, diffusion, and expansion of gases - all increase with an increase in temperature.
Let's summarize the answer:
- Evaporation, the process by which a liquid changes into a vapor or gas, increases with an increase in temperature.
- Diffusion, the movement of particles from an area of higher concentration to an area of lower concentration, increases with an increase in temperature.
- Expansion of gases occurs when the temperature is raised, as the increased kinetic energy of the gas molecules causes them to move faster and occupy a larger volume.
Hence, the correct answer is option 'C': Evaporation, diffusion, expansion of gases.
Explanation:
When the temperature is increased, several physical processes tend to increase. These processes include evaporation, diffusion, and expansion of gases. Let's understand each of these phenomena in detail:
1. Evaporation:
Evaporation is the process by which a liquid changes into a vapor or gas at temperatures below its boiling point. When the temperature is increased, the kinetic energy of the molecules in the liquid also increases. As a result, more molecules gain enough energy to overcome the attractive forces of the liquid and escape into the gas phase. Therefore, evaporation increases with an increase in temperature.
2. Diffusion:
Diffusion is the process of movement of particles from an area of higher concentration to an area of lower concentration. It occurs due to the random motion of particles. When the temperature is increased, the kinetic energy of the particles also increases. This increased kinetic energy leads to faster and more frequent collisions between particles, resulting in an increased rate of diffusion.
3. Expansion of gases:
When gases are heated, their molecules gain kinetic energy and move faster. This increased molecular motion leads to an increase in the volume of the gas because the molecules now occupy a larger space. Therefore, gases expand when the temperature is raised.
These three phenomena - evaporation, diffusion, and expansion of gases - all increase with an increase in temperature.
Let's summarize the answer:
- Evaporation, the process by which a liquid changes into a vapor or gas, increases with an increase in temperature.
- Diffusion, the movement of particles from an area of higher concentration to an area of lower concentration, increases with an increase in temperature.
- Expansion of gases occurs when the temperature is raised, as the increased kinetic energy of the gas molecules causes them to move faster and occupy a larger volume.
Hence, the correct answer is option 'C': Evaporation, diffusion, expansion of gases.
As the solid melts to form liquid,- a)compressibility increases.
- b)interparticle forces of attraction decreases
- c)the kinetic energy of the particle increases
- d)all of these
Correct answer is option 'D'. Can you explain this answer?
As the solid melts to form liquid,
a)
compressibility increases.
b)
interparticle forces of attraction decreases
c)
the kinetic energy of the particle increases
d)
all of these
| | Hansa Sharma answered |
All three phenomena occurs when solid melts to form liquid hence option D is correct.
Liquids can change their shape because:- a)Their particles have very little movement
- b)Their particles move freely and have more space between them
- c)Their particles are tightly packed
- d)Their temperature is high
Correct answer is option 'B'. Can you explain this answer?
a)
Their particles have very little movement
b)
Their particles move freely and have more space between them
c)
Their particles are tightly packed
d)
Their temperature is high
| | Samira Singh answered |
Understanding Liquid Shape Change
Liquids have a unique ability to change their shape, which can be attributed to their molecular structure and behavior. Let’s break down why option 'B' is the correct answer.
Particle Movement
- Liquids consist of particles (molecules) that are not as tightly bound as those in solids.
- These particles are able to move freely past one another, which allows liquids to flow.
Spacing Between Particles
- In liquids, the particles are relatively close together, but there is more space between them compared to solids.
- This spacing enables the particles to slide over each other, facilitating shape change.
Implications of Particle Behavior
- Due to the freedom of movement, when a liquid is poured into a container, it takes the shape of that container.
- The ability of liquid particles to move and rearrange themselves is what allows them to adapt to different shapes.
Contrast with Solids and Gases
- In solids, particles are tightly packed in a fixed arrangement, preventing any shape change.
- In gases, while particles are far apart and move freely, they expand to fill the entire volume of their container, which is different from the shape-changing nature of liquids.
Conclusion
The ability of liquids to change shape is primarily due to the combination of their particle movement and the space between them, making option 'B' the most accurate explanation. Understanding this concept is essential for grasping the behavior of different states of matter.
Liquids have a unique ability to change their shape, which can be attributed to their molecular structure and behavior. Let’s break down why option 'B' is the correct answer.
Particle Movement
- Liquids consist of particles (molecules) that are not as tightly bound as those in solids.
- These particles are able to move freely past one another, which allows liquids to flow.
Spacing Between Particles
- In liquids, the particles are relatively close together, but there is more space between them compared to solids.
- This spacing enables the particles to slide over each other, facilitating shape change.
Implications of Particle Behavior
- Due to the freedom of movement, when a liquid is poured into a container, it takes the shape of that container.
- The ability of liquid particles to move and rearrange themselves is what allows them to adapt to different shapes.
Contrast with Solids and Gases
- In solids, particles are tightly packed in a fixed arrangement, preventing any shape change.
- In gases, while particles are far apart and move freely, they expand to fill the entire volume of their container, which is different from the shape-changing nature of liquids.
Conclusion
The ability of liquids to change shape is primarily due to the combination of their particle movement and the space between them, making option 'B' the most accurate explanation. Understanding this concept is essential for grasping the behavior of different states of matter.
What effect does increasing temperature have on the kinetic energy of particles?- a)It decreases their kinetic energy
- b)It has no effect on their kinetic energy
- c)It increases their kinetic energy
- d)It freezes the particles
Correct answer is option 'C'. Can you explain this answer?
a)
It decreases their kinetic energy
b)
It has no effect on their kinetic energy
c)
It increases their kinetic energy
d)
It freezes the particles
 | Imk Pathshala answered |
As the temperature increases, the kinetic energy of particles also increases. This causes particles to move faster and spread out more, which is why heating a substance often causes it to expand.
Statement A: Celsius scale is the best scale for measuring temperature.
Statement B: CO2 (liquid state) is stored under high pressure.
Which of the two statements is true?- a)Statement A
- b) Neither a nor b
- c)Statement B
- d)Both a and b
Correct answer is option 'C'. Can you explain this answer?
Statement A: Celsius scale is the best scale for measuring temperature.
Statement B: CO2 (liquid state) is stored under high pressure.
Which of the two statements is true?
Statement B: CO2 (liquid state) is stored under high pressure.
Which of the two statements is true?
a)
Statement A
b)
Neither a nor b
c)
Statement B
d)
Both a and b
| | Yashika Gupta answered |
Understanding the Statements
Statement A: "Celsius scale is the best scale for measuring temperature."
Statement B: "CO2 (liquid state) is stored under high pressure."
Analysis of Statement A
- The Celsius scale is widely used for everyday temperature measurement, particularly in most countries.
- However, it may not be the best scale for all scientific applications.
- For example, the Kelvin scale is preferred in scientific contexts as it starts from absolute zero, providing a more accurate representation of thermal energy.
Analysis of Statement B
- Carbon dioxide (CO2) in its liquid state must be stored under high pressure.
- This is necessary because CO2 only becomes liquid at pressures above 5.1 atmospheres at room temperature.
- Hence, storing liquid CO2 requires specialized high-pressure containers to maintain its liquid form.
Conclusion
- Statement A is subjective and not universally true; thus, it is not entirely accurate to claim it is the best scale.
- Statement B is a factual statement regarding the storage of liquid CO2 under high pressure.
Final Answer
- Therefore, the correct answer is option 'C': Statement B is true, while Statement A is not necessarily the best.
Statement A: "Celsius scale is the best scale for measuring temperature."
Statement B: "CO2 (liquid state) is stored under high pressure."
Analysis of Statement A
- The Celsius scale is widely used for everyday temperature measurement, particularly in most countries.
- However, it may not be the best scale for all scientific applications.
- For example, the Kelvin scale is preferred in scientific contexts as it starts from absolute zero, providing a more accurate representation of thermal energy.
Analysis of Statement B
- Carbon dioxide (CO2) in its liquid state must be stored under high pressure.
- This is necessary because CO2 only becomes liquid at pressures above 5.1 atmospheres at room temperature.
- Hence, storing liquid CO2 requires specialized high-pressure containers to maintain its liquid form.
Conclusion
- Statement A is subjective and not universally true; thus, it is not entirely accurate to claim it is the best scale.
- Statement B is a factual statement regarding the storage of liquid CO2 under high pressure.
Final Answer
- Therefore, the correct answer is option 'C': Statement B is true, while Statement A is not necessarily the best.
Practice Test/Quiz or MCQ (Multiple Choice Questions) with Solutions of Chapter "Matter in our surroundings" are available for CBSE Class 9 Science and have been compiled as per the syllabus of CBSE Class 9 Science Q. Which of the following has the strongest interparticle force at the room temperature?- a)Nitrogen
- b)Mercury
- c)Iron
- d)Chalk
Correct answer is 'C'. Can you explain this answer?
Practice Test/Quiz or MCQ (Multiple Choice Questions) with Solutions of Chapter "Matter in our surroundings" are available for CBSE Class 9 Science and have been compiled as per the syllabus of CBSE Class 9 Science
Q. Which of the following has the strongest interparticle force at the room temperature?
a)
Nitrogen
b)
Mercury
c)
Iron
d)
Chalk
 | Shubham Majumdar answered |
Higher the melting point of a substance, greater will be the force of attraction between particles. The melting point of iron is considerably high, so the force of attraction between its particles is higher.
Which of the following does not undergo sublimation? - a)Ammonium chloride
- b)Sodium chloride
- c)Solid carbon dioxide
- d)Iodine
Correct answer is option 'B'. Can you explain this answer?
Which of the following does not undergo sublimation?
a)
Ammonium chloride
b)
Sodium chloride
c)
Solid carbon dioxide
d)
Iodine
| | Ananya Das answered |
Sublimation is when a solid changes directly to gas without changing into liquid.
NaCl when heated does not change its state when heated , while all the other options sublime. Hence sodium chloride is the right answer.
NaCl when heated does not change its state when heated , while all the other options sublime. Hence sodium chloride is the right answer.
Latent heat of fusion is amount of - a)heat energy required to change 1 kg solid into liquid completely at its melting point
- b)heat energy required to convert 1 kg solid into liquid at room temperature
- c)heat energy required to change 1 g of solid into liquid completely
- d)heat energy required to change 1 kg of solid into liquid at any temperature
Correct answer is option 'A'. Can you explain this answer?
Latent heat of fusion is amount of
a)
heat energy required to change 1 kg solid into liquid completely at its melting point
b)
heat energy required to convert 1 kg solid into liquid at room temperature
c)
heat energy required to change 1 g of solid into liquid completely
d)
heat energy required to change 1 kg of solid into liquid at any temperature
| | Sara Khanna answered |
Latent Heat of Fusion
Latent heat of fusion refers to the amount of heat energy required to change 1 kg of solid into a liquid completely at its melting point. This is a specific type of heat energy that is required for a substance to change phases from a solid to a liquid.
Explanation
When a solid substance is heated, its temperature increases until it reaches its melting point. Once the substance reaches its melting point, the heat energy being added is used to break the bonds between the molecules in the solid, allowing the molecules to move more freely and become a liquid. This process requires a certain amount of heat energy, which is known as the latent heat of fusion.
The latent heat of fusion is a specific amount of heat energy that is required to change 1 kg of a substance from a solid to a liquid at its melting point. It is a characteristic property of each substance and is typically measured in units of J/kg.
For example, the latent heat of fusion of water is 334 kJ/kg. This means that it takes 334 kJ of heat energy to melt 1 kg of ice into liquid water at 0°C.
Conclusion
In conclusion, the latent heat of fusion is the amount of heat energy required to change a substance from a solid to a liquid at its melting point. It is a characteristic property of each substance and is typically measured in units of J/kg.
Latent heat of fusion refers to the amount of heat energy required to change 1 kg of solid into a liquid completely at its melting point. This is a specific type of heat energy that is required for a substance to change phases from a solid to a liquid.
Explanation
When a solid substance is heated, its temperature increases until it reaches its melting point. Once the substance reaches its melting point, the heat energy being added is used to break the bonds between the molecules in the solid, allowing the molecules to move more freely and become a liquid. This process requires a certain amount of heat energy, which is known as the latent heat of fusion.
The latent heat of fusion is a specific amount of heat energy that is required to change 1 kg of a substance from a solid to a liquid at its melting point. It is a characteristic property of each substance and is typically measured in units of J/kg.
For example, the latent heat of fusion of water is 334 kJ/kg. This means that it takes 334 kJ of heat energy to melt 1 kg of ice into liquid water at 0°C.
Conclusion
In conclusion, the latent heat of fusion is the amount of heat energy required to change a substance from a solid to a liquid at its melting point. It is a characteristic property of each substance and is typically measured in units of J/kg.
Chapter doubts & questions for Composition of Matter - Maharashtra Board for Class 8 All Subjects 2026 is part of Class 8 exam preparation. The chapters have been prepared according to the Class 8 exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for Class 8 2026 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.
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