- Understand the characteristics of particles of matter.
- Explain the states of matter and their transitions.
- Describe the behavior of particles in solids, liquids, and gases.
- Conduct experiments to observe the movement of particles.
- Convert temperatures between Celsius and Kelvin scales.
- Justify the physical states of substances at various temperatures.
- Analyze the effects of pressure and temperature on states of matter.
Matter in Our Surroundings
CBSE Learning Objectives – Key Concepts & Skills You Must Know
CBSE Revision Notes & Quick Summary for Last-Minute Study
Notes on States of Matter
Temperature Conversion Exercises
- Convert to Celsius:
- (a) 293 K
- (b) 470 K
- Convert to Kelvin:
- (a) 25° C
- (b) 373° C
Observations and Justifications
- Naphthalene Balls: Disappear over time without leaving solid residue.
- Perfume Smell: Can be detected several meters away due to diffusion.
Forces of Attraction
- Substances in Increasing Order of Forces of Attraction:
- Water
- Sugar
- Oxygen
Physical States of Water
- At 25° C: Liquid
- At 0° C: Solid
- At 100° C: Gas
Justifications for Physical States
- Water at Room Temperature:
- It is a liquid due to molecular motion and temperature.
- Iron Almirah at Room Temperature:
- It is a solid due to closely packed particles.
Cooling Effectiveness
- Ice at 273 K vs. Water at 273 K: Ice is more effective in cooling due to its latent heat of fusion.
Severity of Burns
- Boiling Water vs. Steam: Steam produces more severe burns due to higher energy content.
Phase Transition Diagram
- Diagram Components:
- A: Solid
- B: Liquid
- C: Gas
- D, E, F: Not specified
Experimental Setup for Particle Movement
- Materials Needed:
- Transparent jar
- Big rubber balloon or stretchable rubber sheet
- String
- Dried grains (chickpeas or black gram)
- Procedure:
- Place seeds in the jar, secure the rubber sheet, and demonstrate particle movement by tugging the string.
Important Diagrams
- Phase Transitions:
- Solid to Liquid (Fusion)
- Liquid to Gas (Vaporization)
- Gas to Liquid (Condensation)
- Liquid to Solid (Solidification)
- Solid to Gas (Sublimation)
- Gas to Solid (Deposition)
Key Quantities and Units
| Quantity | Unit | Symbol |
|---|---|---|
| Temperature | kelvin | K |
| Length | metre | m |
| Mass | kilogram | kg |
| Weight | newton | N |
| Volume | cubic metre | m³ |
| Density | kilogram per cubic metre | kg m⁻³ |
| Pressure | pascal | Pa |
CBSE Exam Tips, Important Questions & Common Mistakes to Avoid
Common Mistakes and Exam Tips
Common Pitfalls
-
Temperature Conversion Errors: Students often confuse Celsius and Kelvin conversions. Ensure to use the correct formulas:
- For Celsius to Kelvin: K = °C + 273.15
- For Kelvin to Celsius: °C = K - 273.15
-
Forces of Attraction Misunderstanding: When arranging substances by forces of attraction, students may overlook the molecular structure. Remember that solids have stronger forces than liquids, which in turn are stronger than gases.
-
State of Water at Different Temperatures: Students may incorrectly state the physical state of water at various temperatures. Recall:
- Water is a liquid at 25°C.
- Water freezes at 0°C (solid) and boils at 100°C (gas).
-
Misinterpretation of Cooling Effect: Some may think water is more effective in cooling than ice at the same temperature. Remember that ice absorbs more heat during melting, making it more effective for cooling.
-
Burn Severity Confusion: Students might assume boiling water causes more severe burns than steam. However, steam can cause more severe burns due to its higher energy content.
Exam Tips
- Practice Temperature Conversions: Regularly practice converting temperatures between Celsius and Kelvin to avoid mistakes.
- Understand Molecular Structures: Familiarize yourself with the molecular structures of substances to better understand their properties and forces of attraction.
- Memorize Key States of Matter: Keep a quick reference for the physical states of common substances at various temperatures.
- Clarify Concepts of Heat Transfer: Understand the principles of heat transfer and energy changes during phase transitions to answer related questions accurately.
- Review Phase Transition Diagrams: Study diagrams illustrating phase changes to reinforce your understanding of the relationships between solid, liquid, and gas states.
CBSE Quiz & Practice Test – MCQs, True/False Questions with Solutions
Multiple Choice Questions
A.
20°C
B.
25°C
C.
30°C
D.
35°C
Correct Answer: A
Solution:
To convert from Kelvin to Celsius, subtract 273 from the Kelvin temperature: 293 K - 273 = 20°C.
A.
Boiling
B.
Condensation
C.
Sublimation
D.
Melting
Correct Answer: C
Solution:
Camphor undergoes sublimation, which is the process where a solid changes directly into a gas without passing through the liquid state.
A.
Evaporation
B.
Condensation
C.
Sublimation
D.
Melting
Correct Answer: C
Solution:
Sublimation is the process where a solid changes directly to a gas without passing through the liquid state. Camphor is known to undergo sublimation.
A.
Melting
B.
Sublimation
C.
Condensation
D.
Vaporization
Correct Answer: B
Solution:
Sublimation is the process where a solid changes directly to a gas without passing through the liquid state.
A.
Condensation
B.
Sublimation
C.
Vaporisation
D.
Solidification
Correct Answer: B
Solution:
Sublimation is the process where a solid changes directly to a gas without passing through the liquid state.
A.
The pressure decreases.
B.
The pressure remains constant.
C.
The pressure increases.
D.
The gas turns into a liquid.
Correct Answer: C
Solution:
According to Boyle's Law, pressure of a gas increases as the volume decreases if the temperature is kept constant.
A.
They dissolve in air.
B.
They undergo sublimation.
C.
They melt into a liquid.
D.
They are absorbed by the surrounding materials.
Correct Answer: B
Solution:
Naphthalene balls undergo sublimation, changing directly from solid to gas without passing through the liquid state.
A.
The pressure decreases
B.
The pressure remains constant
C.
The pressure increases
D.
The pressure fluctuates
Correct Answer: C
Solution:
According to Boyle's Law, when the volume of a gas is decreased by compressing it, the pressure increases if the temperature remains constant.
A.
Evaporation
B.
Condensation
C.
Sublimation
D.
Fusion
Correct Answer: C
Solution:
Sublimation is the process where a solid changes directly into a gas without passing through the liquid state, as seen with substances like camphor and dry ice.
A.
Solid
B.
Liquid
C.
Gas
D.
Plasma
Correct Answer: B
Solution:
At 25° C, water is in the liquid state.
A.
The particles move further apart.
B.
The particles come closer together.
C.
The particles stop moving.
D.
The particles expand.
Correct Answer: B
Solution:
When a gas is compressed, the particles come closer together, reducing the volume.
A.
334 kJ
B.
668 kJ
C.
500 kJ
D.
1000 kJ
Correct Answer: B
Solution:
The energy required is calculated using the formula: Energy = mass \times latent heat of fusion. Therefore, Energy = 2 kg \times 334 kJ/kg = 668 kJ.
A.
Surface area
B.
Humidity
C.
Wind speed
D.
Color of the liquid
Correct Answer: D
Solution:
The color of the liquid does not affect the rate of evaporation. Factors like surface area, humidity, and wind speed do influence how quickly evaporation occurs.
A.
The liquid will evaporate and increase the pressure inside the container.
B.
The liquid will solidify due to increased temperature.
C.
The liquid will remain unchanged.
D.
The liquid will convert into a solid due to high pressure.
Correct Answer: A
Solution:
As the temperature increases, the liquid will evaporate, causing an increase in pressure inside the sealed container due to the vaporization of the liquid.
A.
It increases the temperature
B.
It decreases the temperature
C.
It has no effect on the temperature
D.
It makes the temperature fluctuate
Correct Answer: B
Solution:
Evaporation causes cooling because particles at the surface gain energy and escape, taking heat away.
A.
Condensation
B.
Sublimation
C.
Deposition
D.
Solidification
Correct Answer: B
Solution:
Sublimation is the process where a solid changes directly into a gas. This requires the absorption of latent heat to overcome the forces of attraction between the particles in the solid state.
A.
Boiling water
B.
Steam
C.
Both are equally severe
D.
Neither causes burns
Correct Answer: B
Solution:
Steam causes more severe burns because it contains more energy due to the latent heat of vaporization.
A.
Ice absorbs more heat due to the latent heat of fusion.
B.
Ice has a higher temperature than water.
C.
Ice releases heat when it melts.
D.
Water has more thermal energy than ice.
Correct Answer: A
Solution:
Ice at 273 K is more effective in cooling because when it melts, it absorbs the latent heat of fusion, which is the energy required to change from solid to liquid without changing temperature.
A.
Boiling
B.
Evaporation
C.
Condensation
D.
Freezing
Correct Answer: B
Solution:
Evaporation is a surface phenomenon where particles from the surface gain enough energy to change into the vapor state.
A.
Increased temperature
B.
Decreased atmospheric pressure
C.
Increased wind speed
D.
Increased humidity
Correct Answer: C
Solution:
Increased wind speed enhances the rate of evaporation by removing the saturated layer of air above the liquid surface, allowing more liquid molecules to escape into the air.
A.
Matter is continuous.
B.
Particles of matter have spaces between them and are in constant motion.
C.
Matter is made up of large, immobile particles.
D.
Matter changes state with temperature.
Correct Answer: B
Solution:
The spreading of perfume smell is due to the diffusion of particles, which demonstrates that particles of matter have spaces between them and are in constant motion.
A.
The water has reached its maximum temperature.
B.
The heat is being used for vaporization.
C.
The water is losing energy to the surroundings.
D.
The water molecules have stopped moving.
Correct Answer: B
Solution:
At 100°C, water reaches its boiling point, and the heat energy is used to change the state from liquid to gas (vaporization), rather than increasing the temperature.
A.
Solid
B.
Liquid
C.
Gas
D.
Plasma
Correct Answer: B
Solution:
At 100°C, water is in the liquid state just before it starts to boil and turn into gas.
A.
Pascal
B.
Newton
C.
Joule
D.
Watt
Correct Answer: A
Solution:
The SI unit of pressure is Pascal (Pa).
A.
The gas particles move closer together.
B.
The gas particles expand and move further apart.
C.
The gas particles remain stationary.
D.
The gas particles change into a liquid.
Correct Answer: A
Solution:
When the volume of the gas is reduced by pushing the piston down, the gas particles are compressed and move closer together, increasing the pressure within the syringe.
A.
The pressure decreases.
B.
The pressure remains constant.
C.
The pressure increases.
D.
The pressure becomes zero.
Correct Answer: C
Solution:
Boyle's Law states that for a given mass of gas at constant temperature, the pressure is inversely proportional to the volume. Thus, reducing the volume increases the pressure.
A.
The water absorbs latent heat of fusion.
B.
The water releases latent heat of vaporization.
C.
The water releases latent heat of fusion.
D.
The water absorbs latent heat of vaporization.
Correct Answer: C
Solution:
When water freezes, it releases latent heat of fusion. This process involves the transition from liquid to solid, where energy is released as the water molecules arrange themselves into a solid structure.
A.
Condensation
B.
Sublimation
C.
Vaporization
D.
Deposition
Correct Answer: B
Solution:
Sublimation is the process where a solid changes directly to a gas without passing through the liquid state.
A.
Molecules become more ordered
B.
Molecules become less ordered
C.
Molecules remain in a fixed position
D.
Molecules move further apart but remain ordered
Correct Answer: B
Solution:
As a solid transitions to a liquid, the molecules become less ordered, allowing them to slip and slide over each other, which is characteristic of the liquid state.
A.
It is a surface phenomenon where only the surface particles gain enough energy to change into vapor.
B.
It is a bulk phenomenon where particles from the bulk of the liquid change into vapor.
C.
It is a process where the temperature of the liquid decreases as it changes into vapor.
D.
It is a process where the liquid absorbs latent heat of fusion.
Correct Answer: B
Solution:
Boiling is a bulk phenomenon where particles from the entire bulk of the liquid gain enough energy to change into the vapor state. This occurs at the boiling point of the liquid.
A.
Naphthalene undergoes sublimation, directly converting from solid to gas.
B.
Naphthalene dissolves in the air.
C.
Naphthalene melts and evaporates.
D.
Naphthalene is absorbed by surrounding materials.
Correct Answer: A
Solution:
Naphthalene undergoes sublimation, which is the process where a solid changes directly into a gas without passing through the liquid state.
A.
Naphthalene balls
B.
Iron nails
C.
Wooden blocks
D.
Glass marbles
Correct Answer: A
Solution:
Naphthalene balls undergo sublimation, turning directly from solid to gas, leaving no residue.
A.
Solids have a definite shape.
B.
Solids are rigid.
C.
Solids have elasticity.
D.
Solids have a fixed volume.
Correct Answer: C
Solution:
The ability of a rubber band to return to its original shape after being stretched demonstrates elasticity, a property of some solids.
A.
Condensation
B.
Deposition
C.
Sublimation
D.
Solidification
Correct Answer: C
Solution:
Sublimation, the process where a solid turns directly into a gas, typically requires an increase in temperature and a decrease in pressure.
A.
Particles in a liquid are tightly packed in a fixed position.
B.
Particles in a liquid are arranged randomly with no fixed position.
C.
Particles in a liquid are loosely packed and can slide past each other.
D.
Particles in a liquid are widely spaced and move freely.
Correct Answer: C
Solution:
In liquids, particles are less tightly packed than in solids and can slide past each other, allowing liquids to flow.
A.
Evaporation
B.
Condensation
C.
Sublimation
D.
Melting
Correct Answer: C
Solution:
Naphthalene undergoes sublimation, changing directly from solid to gas without passing through a liquid state.
A.
It becomes a solid.
B.
It becomes a liquid.
C.
It expands.
D.
It remains unchanged.
Correct Answer: B
Solution:
Increasing pressure on a gas can compress it into a liquid state.
A.
Definite shape and volume
B.
Definite shape but no definite volume
C.
No definite shape but definite volume
D.
No definite shape and no definite volume
Correct Answer: C
Solution:
Liquids have a definite volume but take the shape of their container, meaning they have no definite shape.
A.
Latent heat of vaporization
B.
Latent heat of fusion
C.
Latent heat of sublimation
D.
Latent heat of condensation
Correct Answer: B
Solution:
The latent heat of fusion is the heat energy required to change 1 kg of a solid into a liquid at its melting point without changing its temperature.
A.
Decreasing the surface area
B.
Increasing the humidity
C.
Increasing the wind speed
D.
Decreasing the temperature
Correct Answer: C
Solution:
Increasing wind speed enhances the rate of evaporation by removing the vapor from the liquid's surface more quickly.
A.
Surface area
B.
Temperature
C.
Humidity
D.
Mass
Correct Answer: D
Solution:
The mass of the liquid does not directly affect the rate of evaporation. Factors such as surface area, temperature, and humidity do.
A.
Sublimation
B.
Deposition
C.
Evaporation
D.
Condensation
Correct Answer: B
Solution:
Deposition is the process where gas changes directly to solid without becoming liquid.
A.
The gas will liquefy.
B.
The gas will solidify.
C.
The gas will expand.
D.
The gas will sublimate.
Correct Answer: A
Solution:
Increasing pressure on a gas at constant temperature can lead to liquefaction, as the particles are forced closer together, overcoming the kinetic energy that keeps them apart in the gaseous state.
A.
High density
B.
Low compressibility
C.
Random molecular motion
D.
Fixed volume
Correct Answer: C
Solution:
The ability of the perfume scent to spread throughout the room is due to the random motion of gas molecules, which allows them to diffuse and occupy the available space.
A.
Solid
B.
Liquid
C.
Gas
D.
Plasma
Correct Answer: A
Solution:
Solids have a definite shape and volume due to the fixed arrangement of their particles.
A.
High humidity and low temperature
B.
Low humidity and high temperature
C.
High humidity and high temperature
D.
Low humidity and low temperature
Correct Answer: B
Solution:
Low humidity and high temperature increase the rate of evaporation because there is less moisture in the air to saturate it, and higher temperatures provide more energy for the water molecules to escape into the air.
A.
The heat required to raise the temperature of ice by 1°C.
B.
The heat required to convert 1 kg of ice into water at its melting point.
C.
The heat required to convert 1 kg of water into steam at its boiling point.
D.
The heat required to freeze 1 kg of water at 0°C.
Correct Answer: B
Solution:
Latent heat of fusion is the amount of heat energy required to change 1 kg of a solid into liquid at its melting point without changing its temperature.
A.
Condensation
B.
Boiling
C.
Evaporation
D.
Sublimation
Correct Answer: C
Solution:
Evaporation causes cooling because particles at the surface gain energy and escape, taking away heat.
A.
Matter has mass.
B.
Matter occupies space.
C.
Particles of matter have space between them.
D.
Particles of matter are continuously moving.
Correct Answer: D
Solution:
The spreading of potassium permanganate in water demonstrates that particles of matter are in constant motion, allowing them to diffuse throughout the solution.
A.
Solid
B.
Liquid
C.
Gas
D.
Plasma
Correct Answer: B
Solution:
At 0°C, water is in the liquid state, although it is at the freezing point where it can also exist as ice.
A.
It is a bulk phenomenon where the entire liquid turns into vapor.
B.
It is a surface phenomenon where only surface particles gain energy to become vapor.
C.
It is the process of a solid turning directly into a gas.
D.
It is the cooling of a liquid by removing heat.
Correct Answer: B
Solution:
Evaporation is a surface phenomenon where particles at the surface of a liquid gain enough energy to overcome intermolecular forces and enter the vapor phase.
A.
Solids
B.
Liquids
C.
Gases
D.
Plasma
Correct Answer: C
Solution:
Gases can be compressed easily because their particles are far apart compared to solids and liquids.
A.
They are continuous like a block of wood
B.
They are made up of particles like sand
C.
They have no spaces between them
D.
They are visible to the naked eye
Correct Answer: B
Solution:
Matter is made up of particles, which can be observed through experiments like dissolving salt in water.
A.
All are solids with different compressibility.
B.
The rubber band is a liquid.
C.
The wood is a gas.
D.
The sponge is a liquid.
Correct Answer: A
Solution:
All these materials are solids, but they exhibit different responses to force due to their structural properties. The rubber band and sponge can change shape due to their elasticity and porosity, respectively.
A.
Fusion
B.
Condensation
C.
Vaporisation
D.
Deposition
Correct Answer: C
Solution:
Vaporisation is the process where a liquid changes into a gas.
A.
Sublimation
B.
Deposition
C.
Vaporization
D.
Condensation
Correct Answer: B
Solution:
Deposition is the process where a gas transitions directly into a solid without becoming a liquid first.
A.
Solid
B.
Liquid
C.
Gas
D.
Plasma
Correct Answer: A
Solution:
In solids, particles are arranged in a fixed, orderly structure, making them the most ordered.
A.
The volume of the gas decreases.
B.
The temperature of the gas increases.
C.
The gas turns into a liquid.
D.
The mass of the gas increases.
Correct Answer: A
Solution:
According to the ideal gas law, , where is pressure, is volume, is the number of moles, is the gas constant, and is temperature. If the pressure increases while the temperature remains constant, the volume must decrease to maintain the equality.
A.
Camphor
B.
Water
C.
Iron
D.
Salt
Correct Answer: A
Solution:
Camphor is known to sublimate, meaning it transitions directly from a solid to a gas without passing through the liquid state. This property is not observed in water, iron, or salt under normal conditions.
A.
Water
B.
Sugar
C.
Oxygen
D.
Iron
Correct Answer: C
Solution:
Oxygen, being a gas, has the least force of attraction between its particles compared to liquids and solids.
A.
They move closer together.
B.
They move apart and gain energy.
C.
They become stationary.
D.
They lose energy and slow down.
Correct Answer: B
Solution:
When a liquid is heated, its particles gain energy and move apart, increasing the distance between them.
A.
The dry ice will melt into liquid CO₂.
B.
The dry ice will remain solid.
C.
The dry ice will sublimate directly into gaseous CO₂.
D.
The dry ice will decompose into carbon and oxygen.
Correct Answer: C
Solution:
Dry ice sublimates directly from solid to gas at 1 atmosphere without passing through the liquid state.
A.
They move further apart.
B.
They come closer together.
C.
They remain unchanged.
D.
They become solid.
Correct Answer: B
Solution:
Applying pressure to a gas reduces the space between particles, bringing them closer together.
A.
Diffusion
B.
Sublimation
C.
Evaporation
D.
Condensation
Correct Answer: A
Solution:
Diffusion is the process by which particles spread from an area of higher concentration to an area of lower concentration. The spreading of ink in water is a classic example of diffusion.
A.
Ice absorbs more heat due to latent heat of fusion.
B.
Ice has a higher temperature than water.
C.
Ice releases heat when melting.
D.
Ice is denser than water.
Correct Answer: A
Solution:
Ice at 273 K absorbs more heat from the surroundings due to the latent heat of fusion, making it more effective in cooling.
A.
Water
B.
Sugar
C.
Oxygen
D.
Iron
Correct Answer: C
Solution:
Oxygen, being a gas, has the weakest forces of attraction between its particles compared to liquids and solids.
A.
The particles move further apart.
B.
The particles move closer together.
C.
The particles remain in the same position.
D.
The particles increase in size.
Correct Answer: B
Solution:
When the piston is pushed down, the volume of the gas decreases, causing the particles to move closer together, increasing the pressure.
True or False
Correct Answer: True
Solution:
By applying pressure and reducing temperature, gases can be liquefied as the particles are brought closer together.
Correct Answer: True
Solution:
This process is called sublimation, where a solid changes directly into a gaseous state without becoming liquid.
Correct Answer: False
Solution:
Gases diffuse faster than liquids due to the larger spaces between their particles, allowing them to move more freely.
Correct Answer: True
Solution:
Applying pressure and reducing temperature can liquefy gases, as pressure brings particles closer together.
Correct Answer: False
Solution:
At 0°C, water is at its freezing point and exists in a solid state as ice.
Correct Answer: True
Solution:
Sublimation is defined as the transition of a substance directly from the solid to the gas phase without passing through the intermediate liquid phase.
Correct Answer: False
Solution:
Evaporation is a surface phenomenon, where only particles at the surface gain enough energy to change into vapor.
Correct Answer: False
Solution:
In gases, particles move randomly and are not arranged in a fixed, orderly structure.
Correct Answer: False
Solution:
Boiling is a bulk phenomenon where particles from the entire liquid change into the vapor state. Evaporation, not boiling, is a surface phenomenon.
Correct Answer: True
Solution:
In liquids, layers of particles can slip and slide over each other.
Correct Answer: True
Solution:
In gases, particles move about randomly and do not have a fixed arrangement, unlike solids and liquids.
Correct Answer: True
Solution:
Latent heat of fusion is the amount of heat energy required to change 1 kg of solid into liquid at its melting point.
Correct Answer: True
Solution:
Solids are characterized by having a definite shape and volume, and they are not easily compressible due to the close packing of their particles.
Correct Answer: True
Solution:
The states of matter are inter-convertible by changing temperature or pressure.
Correct Answer: False
Solution:
The rate of evaporation depends on the surface area exposed to the atmosphere; a larger surface area increases the rate of evaporation.
Correct Answer: False
Solution:
The latent heat of vaporisation is the heat energy required to change 1 kg of a liquid to gas at atmospheric pressure at its boiling point.
Correct Answer: True
Solution:
The latent heat of fusion is the heat energy needed to convert 1 kg of a solid into a liquid at its melting point without changing its temperature.
Correct Answer: False
Solution:
In liquids, the particles are not in a fixed, orderly structure; they can slip and slide over each other.
Correct Answer: True
Solution:
Solids have a definite shape and distinct boundaries, making them rigid and able to maintain their shape when force is applied.
Correct Answer: True
Solution:
Sublimation is defined as the change of a solid directly to a gaseous state without passing through the liquid state.
Correct Answer: False
Solution:
The rate of evaporation depends on the surface area exposed to the atmosphere; a larger surface area increases the rate of evaporation.
Correct Answer: True
Solution:
Applying pressure and reducing temperature can liquefy gases by bringing the particles closer together.
Correct Answer: True
Solution:
At 25° C, water is in a liquid state as it is above the freezing point and below the boiling point.
Correct Answer: False
Solution:
Latent heat of fusion is the amount of heat energy required to change 1 kg of solid into liquid at its melting point.
Correct Answer: False
Solution:
Evaporation is a surface phenomenon where only particles from the surface of the liquid gain enough energy to change into vapor.