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Questions and Answers
During the process of melting, what happens to the temperature of the system?
During the process of melting, what happens to the temperature of the system?
What is the name of the process where a solid changes directly into a gas?
What is the name of the process where a solid changes directly into a gas?
What happens to the particles in steam?
What happens to the particles in steam?
How can the state of matter be changed into another state?
How can the state of matter be changed into another state?
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What is the SI unit of temperature?
What is the SI unit of temperature?
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How do you convert a temperature on the Celsius scale to the Kelvin scale?
How do you convert a temperature on the Celsius scale to the Kelvin scale?
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What happens to the particles when the pressure is increased on a substance enclosed in a cylinder?
What happens to the particles when the pressure is increased on a substance enclosed in a cylinder?
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What can be inferred about the state of matter?
What can be inferred about the state of matter?
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What is a characteristic of a pure substance?
What is a characteristic of a pure substance?
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Why can soft drink and soil not be considered pure substances?
Why can soft drink and soil not be considered pure substances?
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What does the term 'pure' mean to a common person?
What does the term 'pure' mean to a common person?
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What is milk an example of?
What is milk an example of?
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Why are milk, ghee, and butter not considered pure substances?
Why are milk, ghee, and butter not considered pure substances?
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What can be said about the composition of a pure substance?
What can be said about the composition of a pure substance?
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What is the main difference between a pure substance and a mixture?
What is the main difference between a pure substance and a mixture?
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Who is the Professor and Head of the Department of Education in Science and Mathematics at NCERT?
Who is the Professor and Head of the Department of Education in Science and Mathematics at NCERT?
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What is the title of the chapter that starts on page 1 of the textbook?
What is the title of the chapter that starts on page 1 of the textbook?
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Why can sugar be considered a pure substance?
Why can sugar be considered a pure substance?
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Who is the Incharge of the Computer Centre at DESM?
Who is the Incharge of the Computer Centre at DESM?
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What is the title of the section that starts on page v of the textbook?
What is the title of the section that starts on page v of the textbook?
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Who is the Principal (Retd.) from Delhi?
Who is the Principal (Retd.) from Delhi?
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What is the page number of the chapter 'Is Matter Around Us Pure?'?
What is the page number of the chapter 'Is Matter Around Us Pure?'?
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Who is the TGT in Science from JNV, Meerut?
Who is the TGT in Science from JNV, Meerut?
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What is the year mentioned in the textbook?
What is the year mentioned in the textbook?
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What happens to the particles when a suspension breaks?
What happens to the particles when a suspension breaks?
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What is the mass percentage of the solution in Example 2.1?
What is the mass percentage of the solution in Example 2.1?
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What is a characteristic of a colloidal solution?
What is a characteristic of a colloidal solution?
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Why can colloidal particles scatter a beam of visible light?
Why can colloidal particles scatter a beam of visible light?
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What is an example of a colloidal solution?
What is an example of a colloidal solution?
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What can be said about the particles of a suspension and a colloidal solution?
What can be said about the particles of a suspension and a colloidal solution?
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What happens to the mixture obtained by group D in activity 2.2?
What happens to the mixture obtained by group D in activity 2.2?
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Why can't we see colloidal particles with naked eyes?
Why can't we see colloidal particles with naked eyes?
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What is the unit of pressure exerted by a gas?
What is the unit of pressure exerted by a gas?
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What is the normal atmospheric pressure at sea level?
What is the normal atmospheric pressure at sea level?
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What is the temperature of water in Celsius at 573 K?
What is the temperature of water in Celsius at 573 K?
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Why does the temperature remain constant during the change of state?
Why does the temperature remain constant during the change of state?
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What can be inferred about the effect of temperature, surface area, and wind velocity on evaporation?
What can be inferred about the effect of temperature, surface area, and wind velocity on evaporation?
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What is the physical state of water at 250°C?
What is the physical state of water at 250°C?
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What is the method to liquefy atmospheric gases?
What is the method to liquefy atmospheric gases?
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What is the conversion of 1 atmosphere to Pascal?
What is the conversion of 1 atmosphere to Pascal?
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What is the primary reason solid carbon dioxide is also known as dry ice?
What is the primary reason solid carbon dioxide is also known as dry ice?
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What is the effect of increasing pressure on the state of a substance?
What is the effect of increasing pressure on the state of a substance?
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What is the process called when a gas changes directly into a solid?
What is the process called when a gas changes directly into a solid?
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What can be inferred about the state of matter from the camphor experiment?
What can be inferred about the state of matter from the camphor experiment?
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What is the reason for the difference in various states of matter?
What is the reason for the difference in various states of matter?
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What is the effect of decreasing pressure on solid carbon dioxide?
What is the effect of decreasing pressure on solid carbon dioxide?
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What is the primary reason for the change in state of a substance?
What is the primary reason for the change in state of a substance?
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What can be said about the process of sublimation?
What can be said about the process of sublimation?
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What is the primary criterion for a substance to be considered pure?
What is the primary criterion for a substance to be considered pure?
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What is the main difference between a mixture and a pure substance?
What is the main difference between a mixture and a pure substance?
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What is the significance of the experiment conducted by Group A and Group B?
What is the significance of the experiment conducted by Group A and Group B?
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What is the term used to describe a mixture that has a uniform composition throughout?
What is the term used to describe a mixture that has a uniform composition throughout?
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What is the primary characteristic of a homogeneous mixture?
What is the primary characteristic of a homogeneous mixture?
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What can be said about the composition of a mixture?
What can be said about the composition of a mixture?
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What is the significance of the concept of purity in chemistry?
What is the significance of the concept of purity in chemistry?
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What can be inferred about the particles of a mixture?
What can be inferred about the particles of a mixture?
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What is the minimum number of particles of potassium permanganate required to colour a large volume of water?
What is the minimum number of particles of potassium permanganate required to colour a large volume of water?
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What is the primary reason why the smell of incense can be detected even at a distance?
What is the primary reason why the smell of incense can be detected even at a distance?
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What is the primary reason why the colour of the ink spreads evenly throughout the water in the beaker?
What is the primary reason why the colour of the ink spreads evenly throughout the water in the beaker?
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What is the effect of repeated dilution on the colour of the solution?
What is the effect of repeated dilution on the colour of the solution?
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What can be concluded about the size of the particles of matter from the experiment?
What can be concluded about the size of the particles of matter from the experiment?
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What is the purpose of adding honey to the second beaker in the experiment?
What is the purpose of adding honey to the second beaker in the experiment?
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What is the time required for the colour of the ink to spread evenly throughout the water?
What is the time required for the colour of the ink to spread evenly throughout the water?
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What is the significance of the experiment with incense and water?
What is the significance of the experiment with incense and water?
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What is the address of the Dhankal Bus Stop?
What is the address of the Dhankal Bus Stop?
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What is the name of the Chief Editor of the Publication?
What is the name of the Chief Editor of the Publication?
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What is the paper quality used for printing?
What is the paper quality used for printing?
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What is the location of the SDA Print ‘N’ Pack?
What is the location of the SDA Print ‘N’ Pack?
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In which state of matter are the forces of attraction between particles maximum?
In which state of matter are the forces of attraction between particles maximum?
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What is the year mentioned in the foreword?
What is the year mentioned in the foreword?
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What is the arrangement of particles in solids?
What is the arrangement of particles in solids?
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What is the recommendation of the National Curriculum Framework (NCF) 2005?
What is the recommendation of the National Curriculum Framework (NCF) 2005?
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What is the process of changing from solid state directly to gaseous state without going through liquid state?
What is the process of changing from solid state directly to gaseous state without going through liquid state?
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What is the price of the publication?
What is the price of the publication?
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What is the characteristic of particles in gases?
What is the characteristic of particles in gases?
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Who is the Head of the Publication Division?
Who is the Head of the Publication Division?
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What is the process of changing from gaseous state directly to solid state without going through liquid state?
What is the process of changing from gaseous state directly to solid state without going through liquid state?
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What is the characteristic of boiling?
What is the characteristic of boiling?
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What happens to the particles during evaporation?
What happens to the particles during evaporation?
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What is the difference between evaporation and boiling?
What is the difference between evaporation and boiling?
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What is the characteristic of a homogeneous mixture?
What is the characteristic of a homogeneous mixture?
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What is an example of a heterogeneous mixture?
What is an example of a heterogeneous mixture?
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What can be inferred about the colour of the solutions obtained by groups A and B?
What can be inferred about the colour of the solutions obtained by groups A and B?
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What is a solution?
What is a solution?
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Why are groups C and D heterogeneous mixtures?
Why are groups C and D heterogeneous mixtures?
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What can be said about the composition of the solutions obtained by groups A and B?
What can be said about the composition of the solutions obtained by groups A and B?
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What is the difference between groups A and B?
What is the difference between groups A and B?
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What can be said about the samples distributed to each group?
What can be said about the samples distributed to each group?
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What is the primary reason for the increase in kinetic energy of particles with an increase in temperature?
What is the primary reason for the increase in kinetic energy of particles with an increase in temperature?
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What is the term for the intermixing of particles of two different types of matter on their own?
What is the term for the intermixing of particles of two different types of matter on their own?
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Which of the following substances do you think the particles are held together with the greatest force?
Which of the following substances do you think the particles are held together with the greatest force?
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What happens to the particles of matter when they are heated?
What happens to the particles of matter when they are heated?
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What is the reason for the increase in the rate of diffusion with an increase in temperature?
What is the reason for the increase in the rate of diffusion with an increase in temperature?
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What is the effect of increasing the temperature on the kinetic energy of particles of matter?
What is the effect of increasing the temperature on the kinetic energy of particles of matter?
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What is the term for the force of attraction between particles of matter?
What is the term for the force of attraction between particles of matter?
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What is the primary reason for the diffusion of particles of different types of matter?
What is the primary reason for the diffusion of particles of different types of matter?
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What is the key characteristic that distinguishes an element from other forms of matter?
What is the key characteristic that distinguishes an element from other forms of matter?
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Which of the following properties is NOT characteristic of metals?
Which of the following properties is NOT characteristic of metals?
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What is the primary difference between water and cooking oil?
What is the primary difference between water and cooking oil?
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Who is credited with establishing an experimentally useful definition of an element?
Who is credited with establishing an experimentally useful definition of an element?
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What is the term for a change in chemical composition that occurs when one substance reacts with another?
What is the term for a change in chemical composition that occurs when one substance reacts with another?
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What is the term for the change in chemical properties of matter that occurs during a chemical reaction?
What is the term for the change in chemical properties of matter that occurs during a chemical reaction?
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Which of the following is an example of a chemical change?
Which of the following is an example of a chemical change?
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What is the term for the process of a substance reacting with another to undergo a change in chemical composition?
What is the term for the process of a substance reacting with another to undergo a change in chemical composition?
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What is the primary reason for the increase in rate of evaporation when the surface area is increased?
What is the primary reason for the increase in rate of evaporation when the surface area is increased?
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What happens to the particles of a liquid when it changes into vapour?
What happens to the particles of a liquid when it changes into vapour?
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What is the effect of increase in temperature on the rate of evaporation?
What is the effect of increase in temperature on the rate of evaporation?
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What happens to the rate of evaporation when the humidity of the surrounding air is high?
What happens to the rate of evaporation when the humidity of the surrounding air is high?
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What is the reason for water left uncovered to change into vapour slowly?
What is the reason for water left uncovered to change into vapour slowly?
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What is the effect of spreading clothes out to dry on the rate of evaporation?
What is the effect of spreading clothes out to dry on the rate of evaporation?
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What is the reason for the particles in a liquid to always be moving?
What is the reason for the particles in a liquid to always be moving?
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At a given temperature, what is true about the particles in a gas, liquid, or solid?
At a given temperature, what is true about the particles in a gas, liquid, or solid?
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What is the primary reason why the fourth group of students was able to break the human chains formed by the other groups?
What is the primary reason why the fourth group of students was able to break the human chains formed by the other groups?
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What can be inferred about the state of matter of the sugar or salt crystals?
What can be inferred about the state of matter of the sugar or salt crystals?
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What is the reason why the sponge can be compressed?
What is the reason why the sponge can be compressed?
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What is the characteristic of the particles of matter in a solid state?
What is the characteristic of the particles of matter in a solid state?
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What can be said about the diver who is able to cut through water in a swimming pool?
What can be said about the diver who is able to cut through water in a swimming pool?
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What is the primary reason why cold food has a weaker smell?
What is the primary reason why cold food has a weaker smell?
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What is the characteristic of the particles of matter in a gas state?
What is the characteristic of the particles of matter in a gas state?
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What is the primary reason why the three human chains were able to maintain their shape?
What is the primary reason why the three human chains were able to maintain their shape?
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What is the minimum number of particles of potassium permanganate required to colour a large volume of water?
What is the minimum number of particles of potassium permanganate required to colour a large volume of water?
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What happens when you add a drop of blue or red ink to a beaker of water?
What happens when you add a drop of blue or red ink to a beaker of water?
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What is the purpose of the experiment with incense sticks?
What is the purpose of the experiment with incense sticks?
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What happens when you add honey to a beaker of water?
What happens when you add honey to a beaker of water?
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What is the significance of the activity with potassium permanganate?
What is the significance of the activity with potassium permanganate?
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What can be inferred about the particles of matter from the activities?
What can be inferred about the particles of matter from the activities?
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What is the common theme among the activities with incense sticks, ink, honey, and potassium permanganate?
What is the common theme among the activities with incense sticks, ink, honey, and potassium permanganate?
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What can be said about the particles of potassium permanganate?
What can be said about the particles of potassium permanganate?
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What is the primary goal of the National Policy on Education (1986) in terms of education?
What is the primary goal of the National Policy on Education (1986) in terms of education?
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What is the purpose of discouraging sharp boundaries between different subject areas?
What is the purpose of discouraging sharp boundaries between different subject areas?
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What is the role of school principals and teachers in implementing a child-centered system of education?
What is the role of school principals and teachers in implementing a child-centered system of education?
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What is the significance of flexibility in the daily time-table in achieving the goals of the National Policy on Education (1986)?
What is the significance of flexibility in the daily time-table in achieving the goals of the National Policy on Education (1986)?
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What is the impact of treating children as participants in learning rather than receivers of a fixed body of knowledge?
What is the impact of treating children as participants in learning rather than receivers of a fixed body of knowledge?
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What is the primary reason for restructuring and reorienting knowledge at different stages in the curriculum?
What is the primary reason for restructuring and reorienting knowledge at different stages in the curriculum?
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What is the impact of the current education system on the gap between the school, home, and community?
What is the impact of the current education system on the gap between the school, home, and community?
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What is the significance of inculcating creativity and initiative in children?
What is the significance of inculcating creativity and initiative in children?
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What happens to the temperature of the system during the conversion of ice to water?
What happens to the temperature of the system during the conversion of ice to water?
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What is the term used to describe the heat energy required to change 1 kg of a solid into a liquid at atmospheric pressure at its melting point?
What is the term used to describe the heat energy required to change 1 kg of a solid into a liquid at atmospheric pressure at its melting point?
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What happens to the particles in water at 0°C (273 K) compared to particles in ice at the same temperature?
What happens to the particles in water at 0°C (273 K) compared to particles in ice at the same temperature?
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What is the result of supplying heat energy to water particles?
What is the result of supplying heat energy to water particles?
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What is the state of matter of the substance when it is changing from liquid to gas?
What is the state of matter of the substance when it is changing from liquid to gas?
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What is the term used to describe the heat energy that gets 'hidden' into the contents of the beaker during the conversion of ice to water?
What is the term used to describe the heat energy that gets 'hidden' into the contents of the beaker during the conversion of ice to water?
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What is the reason for the constant temperature during the conversion of solid to liquid state?
What is the reason for the constant temperature during the conversion of solid to liquid state?
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What is the result of heating the water in the beaker with the glass rod?
What is the result of heating the water in the beaker with the glass rod?
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What is the only metal that is liquid at room temperature?
What is the only metal that is liquid at room temperature?
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Which of the following is NOT a characteristic of non-metals?
Which of the following is NOT a characteristic of non-metals?
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What is the term used to describe elements that have intermediate properties between metals and non-metals?
What is the term used to describe elements that have intermediate properties between metals and non-metals?
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Which of the following processes is an example of a physical change?
Which of the following processes is an example of a physical change?
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What is the primary reason why some elements cannot be classified as purely metals or non-metals?
What is the primary reason why some elements cannot be classified as purely metals or non-metals?
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What is the term used to describe the process of passing an electric current through a substance?
What is the term used to describe the process of passing an electric current through a substance?
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Which of the following is an example of a chemical change?
Which of the following is an example of a chemical change?
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What is the primary reason why some elements are classified as metals or non-metals based on their properties?
What is the primary reason why some elements are classified as metals or non-metals based on their properties?
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What is the primary characteristic of a mixture?
What is the primary characteristic of a mixture?
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What is the term used to describe the major component of a solution?
What is the term used to describe the major component of a solution?
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What type of mixture is characterized by particles that are visible to the naked eye?
What type of mixture is characterized by particles that are visible to the naked eye?
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What is the term used to describe a substance that cannot be broken down by chemical reactions into simpler substances?
What is the term used to describe a substance that cannot be broken down by chemical reactions into simpler substances?
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What is the term used to describe the dispersed phase in a colloid?
What is the term used to describe the dispersed phase in a colloid?
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What is the primary characteristic of a pure substance?
What is the primary characteristic of a pure substance?
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What is the term used to describe a substance composed of two or more different types of elements, chemically combined in a fixed proportion?
What is the term used to describe a substance composed of two or more different types of elements, chemically combined in a fixed proportion?
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What is the relative arrangement of particles in solids, liquids, and gases?
What is the relative arrangement of particles in solids, liquids, and gases?
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What happens to the kinetic energy of particles as you move from solids to gases?
What happens to the kinetic energy of particles as you move from solids to gases?
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What is the characteristic of the spaces between particles in gases?
What is the characteristic of the spaces between particles in gases?
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What is the phenomenon where particles change from the surface of a liquid to the vapour state?
What is the phenomenon where particles change from the surface of a liquid to the vapour state?
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What is the process where a gas changes directly to a solid without going through the liquid state?
What is the process where a gas changes directly to a solid without going through the liquid state?
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What is the primary reason for the difference in the states of matter?
What is the primary reason for the difference in the states of matter?
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Which state of matter has the most ordered arrangement of particles?
Which state of matter has the most ordered arrangement of particles?
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What is the term for the change of solid state directly to gaseous state without going through the liquid state?
What is the term for the change of solid state directly to gaseous state without going through the liquid state?
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What is the main objective of the National Education Policy 2020 in terms of content load?
What is the main objective of the National Education Policy 2020 in terms of content load?
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What is one of the reasons for rationalizing the contents of textbooks across all classes?
What is one of the reasons for rationalizing the contents of textbooks across all classes?
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Who is the Chairman of the Advisory Group for Textbooks in Science and Mathematics?
Who is the Chairman of the Advisory Group for Textbooks in Science and Mathematics?
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What is the role of Anjni Koul in the Textbook Development Committee?
What is the role of Anjni Koul in the Textbook Development Committee?
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What is the title of the position held by Rupamanjari Ghosh in the Textbook Development Committee?
What is the title of the position held by Rupamanjari Ghosh in the Textbook Development Committee?
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In what year is the present edition of the textbook published?
In what year is the present edition of the textbook published?
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What is the role of Asfa M.Yasin in the Textbook Development Committee?
What is the role of Asfa M.Yasin in the Textbook Development Committee?
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What is the institution where Anuradha Gulati is a TGT?
What is the institution where Anuradha Gulati is a TGT?
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What is the characteristic of metals that is not true for non-metals?
What is the characteristic of metals that is not true for non-metals?
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Which of the following is an example of a metalloid?
Which of the following is an example of a metalloid?
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What is the process called when a substance breaks down into two or more substances?
What is the process called when a substance breaks down into two or more substances?
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What is the characteristic of non-metals that is not true for metals?
What is the characteristic of non-metals that is not true for metals?
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What is the result of passing an electric current through water?
What is the result of passing an electric current through water?
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What is the difference between a mixture and a pure substance?
What is the difference between a mixture and a pure substance?
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Which metal is liquid at room temperature?
Which metal is liquid at room temperature?
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What is the result of dissolving common salt in water?
What is the result of dissolving common salt in water?
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What is the primary characteristic of a heterogeneous mixture?
What is the primary characteristic of a heterogeneous mixture?
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What is the main difference between a sol and a solution?
What is the main difference between a sol and a solution?
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What is the purpose of centrifugation in the separation of colloidal particles?
What is the purpose of centrifugation in the separation of colloidal particles?
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What is the dispersed phase in a colloidal solution?
What is the dispersed phase in a colloidal solution?
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What is the characteristic of a colloidal solution that distinguishes it from a suspension?
What is the characteristic of a colloidal solution that distinguishes it from a suspension?
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What is the purpose of filtration in the separation of mixtures?
What is the purpose of filtration in the separation of mixtures?
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What is the difference between a homogeneous mixture and a heterogeneous mixture?
What is the difference between a homogeneous mixture and a heterogeneous mixture?
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What is the classification of colloids based on?
What is the classification of colloids based on?
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What is the main characteristic of a solution?
What is the main characteristic of a solution?
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What is the dispersed phase in a colloid?
What is the dispersed phase in a colloid?
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What is the primary difference between a mixture and a pure substance?
What is the primary difference between a mixture and a pure substance?
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What is the term for the amount of solute present per unit volume or per unit mass of the solution?
What is the term for the amount of solute present per unit volume or per unit mass of the solution?
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What is the definition of an element?
What is the definition of an element?
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What is the characteristic of a suspension?
What is the characteristic of a suspension?
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What is the medium in which the particles are distributed in a colloid?
What is the medium in which the particles are distributed in a colloid?
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What is the characteristic of a compound?
What is the characteristic of a compound?
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What is the primary reason for the increase in kinetic energy of particles as temperature rises?
What is the primary reason for the increase in kinetic energy of particles as temperature rises?
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What is the term used to describe the intermixing of particles of two different types of matter on their own?
What is the term used to describe the intermixing of particles of two different types of matter on their own?
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What can be inferred about the force of attraction between particles of matter in a substance?
What can be inferred about the force of attraction between particles of matter in a substance?
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What happens to the particles of matter when they are heated?
What happens to the particles of matter when they are heated?
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What can be said about the particles of matter in a substance?
What can be said about the particles of matter in a substance?
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Why do particles of matter attract each other?
Why do particles of matter attract each other?
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What is the result of the intermixing of particles of two different types of matter?
What is the result of the intermixing of particles of two different types of matter?
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What is the term used to describe the energy of motion possessed by particles of matter?
What is the term used to describe the energy of motion possessed by particles of matter?
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What is the primary factor that affects the rate of evaporation?
What is the primary factor that affects the rate of evaporation?
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What is the primary reason why wearing cotton clothes in summer helps to keep us cool?
What is the primary reason why wearing cotton clothes in summer helps to keep us cool?
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What is the heat energy required to change 1 kg of a liquid to gas at atmospheric pressure at its boiling point?
What is the heat energy required to change 1 kg of a liquid to gas at atmospheric pressure at its boiling point?
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What is the unit of measurement for the density of a substance?
What is the unit of measurement for the density of a substance?
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Why does a desert cooler cool better on a hot dry day?
Why does a desert cooler cool better on a hot dry day?
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What is the reason why we can feel the effect of cooling due to evaporation in our daily life?
What is the reason why we can feel the effect of cooling due to evaporation in our daily life?
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What is the process called when a liquid changes into a gas?
What is the process called when a liquid changes into a gas?
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What is the amount of heat energy required to change 1 kg of solid into liquid at its melting point?
What is the amount of heat energy required to change 1 kg of solid into liquid at its melting point?
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Why does our palm feel cold when we put some acetone or petrol on it?
Why does our palm feel cold when we put some acetone or petrol on it?
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Why are we able to sip hot tea or milk faster from a saucer rather than a cup?
Why are we able to sip hot tea or milk faster from a saucer rather than a cup?
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What is the unit of measurement for the weight of an object?
What is the unit of measurement for the weight of an object?
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What is the effect of evaporation on the temperature of the surroundings?
What is the effect of evaporation on the temperature of the surroundings?
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What is the reason behind the formation of water droplets on the outer surface of a tumbler after a hot sunny day?
What is the reason behind the formation of water droplets on the outer surface of a tumbler after a hot sunny day?
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Why does the body temperature remain constant during the process of sweating?
Why does the body temperature remain constant during the process of sweating?
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What is the temperature in Celsius of 293 K?
What is the temperature in Celsius of 293 K?
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What is the primary reason why water kept in an earthen pot (matka) becomes cool during summer?
What is the primary reason why water kept in an earthen pot (matka) becomes cool during summer?
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What is the primary reason for the ordered arrangement of particles in solids?
What is the primary reason for the ordered arrangement of particles in solids?
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Which of the following statements is true about the changes of state of matter?
Which of the following statements is true about the changes of state of matter?
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What is the primary difference between evaporation and boiling?
What is the primary difference between evaporation and boiling?
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Which of the following is NOT a characteristic of gases?
Which of the following is NOT a characteristic of gases?
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What is the primary reason for the minimum spaces between particles in solids?
What is the primary reason for the minimum spaces between particles in solids?
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Which of the following statements is true about the arrangement of particles in liquids?
Which of the following statements is true about the arrangement of particles in liquids?
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What is the primary reason for the inter-convertibility of states of matter?
What is the primary reason for the inter-convertibility of states of matter?
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Which of the following is a characteristic of deposition?
Which of the following is a characteristic of deposition?
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What is the characteristic of a solution that indicates its stability?
What is the characteristic of a solution that indicates its stability?
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What is the formula to express the concentration of a solution in terms of mass by mass percentage?
What is the formula to express the concentration of a solution in terms of mass by mass percentage?
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What is the difference between a suspension and a solution?
What is the difference between a suspension and a solution?
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What is the method of separation used for a suspension?
What is the method of separation used for a suspension?
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What is the formula to express the concentration of a solution in terms of volume by volume percentage?
What is the formula to express the concentration of a solution in terms of volume by volume percentage?
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What can be inferred about the particles of a solution?
What can be inferred about the particles of a solution?
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What is the characteristic of a suspension that indicates its instability?
What is the characteristic of a suspension that indicates its instability?
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What is the difference between mass by mass percentage and mass by volume percentage?
What is the difference between mass by mass percentage and mass by volume percentage?
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Study Notes
Matter in Our Surroundings
- Matter can be solid, liquid, or gas, and its state can be changed by changing the temperature.
- During the process of melting, the temperature remains the same, and the heat energy is used to change the state of matter.
- The state of matter can be changed into another state by changing the temperature.
- Some substances change directly from solid to gaseous state and vice versa without changing into the liquid state.
Temperature Scales
- The Kelvin scale is the SI unit of temperature, where 0°C = 273.15 K.
- To convert a temperature on the Celsius scale to the Kelvin scale, add 273 to the given temperature.
Pressure and State of Matter
- Increasing or decreasing pressure can change the state of matter.
- The unit of pressure is Pascal (Pa), and 1 atmosphere = 1.01 × 10^5 Pa.
- Atmospheric pressure at sea level is 1 atmosphere, and is taken as the normal atmospheric pressure.
Questions and Activities
- Convert temperatures from the Kelvin scale to the Celsius scale and vice versa.
- Observe and record the evaporation process and the effect of temperature, surface area, and wind velocity on evaporation.
- Suggest a method to liquefy atmospheric gases.
Is Matter Around Us Pure?
- A pure substance has the same characteristic properties throughout and cannot be separated into its chemical constituents by physical process.
- A mixture contains more than one pure substance and can be classified into different types based on the nature of the components.
- Examples of pure substances include sugar, and examples of mixtures include milk, ghee, butter, salt, spices, mineral water, and juice.
Types of Mixtures
- Depending on the nature of the components, mixtures can be classified into different types.
- A suspension is a mixture in which the particles settle down, and a colloid is a mixture in which the particles are uniformly spread throughout the solution.
Concentration of Solutions
- The concentration of a solution can be calculated by finding the mass percentage of the solute.
- Example: A solution contains 40 g of common salt in 320 g of water. The concentration of the solution is 11.11% mass percentage.
Characteristics of Matter
- Matter can be divided into smaller and smaller particles, which are still visible even after repeated dilution.
- The smell of an incense stick can be detected even at a distance, showing that particles of matter can spread out and mix with the air.
States of Matter
- The states of matter are inter-convertible by changing temperature or pressure.
- The difference in states of matter is due to the difference in distances between the constituent particles.
- The forces of attraction between particles are maximum in solids, intermediate in liquids, and minimum in gases.
- The spaces between particles and kinetic energy are minimum in solids, intermediate in liquids, and maximum in gases.
- The arrangement of particles is most ordered in solids, intermediate in liquids, and random in gases.
Sublimation and Deposition
- Sublimation is the change of solid state directly to gaseous state without going through liquid state.
- Deposition is the change of gaseous state directly to solid state without going through liquid state.
- Examples of sublimation and deposition are solid carbon dioxide (CO2) and camphor.
Boiling and Evaporation
- Boiling is a bulk phenomenon where particles from the bulk of the liquid change into vapor state.
- Evaporation is a surface phenomenon where particles from the surface gain enough energy to overcome the forces of attraction and change into vapor state.
Pure Substances and Mixtures
- A pure substance consists of a single type of particle and has a uniform chemical nature.
- A mixture is constituted by more than one kind of pure form of matter.
- Examples of mixtures are sea water, minerals, and soil.
- Homogeneous mixtures or solutions have a uniform composition throughout, such as salt dissolved in water and sugar dissolved in water.
Particles of Matter
- Particles of matter possess kinetic energy and are continuously moving.
- As temperature rises, particles move faster and kinetic energy increases.
- Particles of matter intermix on their own, a process called diffusion, which becomes faster with heating.
Attraction between Particles of Matter
- Particles of matter attract each other.
- The strength of attraction between particles determines the state of matter (solid, liquid, or gas).
- In solids, particles are held together with maximum force, while in gases, they are freely moving.
States of Matter
- Matter exists in three states: solid, liquid, and gas.
- Characteristics of particles of matter vary between these states.
Evaporation
- Evaporation is a surface phenomenon that increases with an increase in surface area.
- Rate of evaporation increases with an increase in temperature.
- Rate of evaporation decreases with an increase in humidity.
Mixtures
- A homogeneous mixture has a uniform composition, e.g., copper sulphate solution.
- A heterogeneous mixture has a non-uniform composition, e.g., mixtures of sodium chloride and iron filings, salt and sulphur, or oil and water.
Solutions
- A solution is a homogeneous mixture of two or more substances.
- Solutions can be found in daily life, e.g., lemonade, soda water.
Elements
- An element is a basic form of matter that cannot be broken down into simpler substances by chemical reactions.
- Elements can be divided into metals, non-metals, and metalloids.
- Metals typically have properties such as lustre, conductivity, ductility, and malleability.
Principles of Child-Centered Education
- The National Curriculum Framework (NCF) aims to shift from a traditional, book-based learning approach to a child-centered system.
- The new syllabi and textbooks are designed to discourage rote learning and promote integration of subjects.
- The success of this approach depends on teachers encouraging children to reflect on their learning and pursue creative activities.
Properties of Matter
- Matter can be divided into smaller particles, which can still maintain their properties.
- A few crystals of potassium permanganate can color a large volume of water, indicating the presence of millions of tiny particles.
- The smell of incense can be detected even after repeated dilution, showing that particles can still be active even when dispersed.
Physical Changes
- Physical changes involve a change in state, but the particles remain the same.
- Examples of physical changes include melting of ice, boiling of water, and dissolving of common salt in water.
Chemical Changes
- Chemical changes involve a change in the composition of particles, resulting in a new substance.
- Examples of chemical changes include rusting of iron, cutting of trees, and passing of electric current through water.
Metals and Non-Metals
- Metals are typically shiny, malleable, and good conductors of heat and electricity.
- Examples of metals include gold, silver, copper, and iron.
- Non-metals are typically dull, brittle, and poor conductors of heat and electricity.
- Examples of non-metals include hydrogen, oxygen, iodine, and carbon.
Mixtures and Solutions
- A mixture contains two or more substances mixed in any proportion.
- Solutions are homogeneous mixtures of two or more substances, with a major component (solvent) and a minor component (solute).
- Suspensions are heterogeneous mixtures with particles visible to the naked eye.
- Colloids are heterogeneous mixtures with particle sizes too small to be seen with the naked eye, but big enough to scatter light.
Pure Substances
- Pure substances can be either elements or compounds.
- Elements are substances that cannot be broken down by chemical reactions into simpler substances.
- Compounds are substances composed of two or more different types of elements, chemically combined in a fixed proportion.
National Education Policy 2020
- Emphasizes reducing content load and providing opportunities for experiential learning with a creative mindset.
- NCERT has undertaken the exercise to rationalize textbooks across all classes, taking into consideration Learning Outcomes developed by NCERT.
Textbook Development Committee
- Chairman: J.V. Narlikar, Emeritus Professor
- Chief Advisor: Rupamanjari Ghosh, Professor
- Members: Various experts in science and mathematics education
States of Matter
- Solids: maximum forces of attraction, minimum kinetic energy, most ordered arrangement of particles
- Liquids: intermediate forces of attraction, intermediate kinetic energy, particles can slip and slide over each other
- Gases: minimum forces of attraction, maximum kinetic energy, particles move randomly
- States of matter are inter-convertible by changing temperature or pressure
- Sublimation: change of solid state directly to gaseous state without going through liquid state
- Deposition: change of gaseous state directly to solid state without going through liquid state
- Boiling: bulk phenomenon where particles from the bulk of the liquid change into vapor state
- Evaporation: surface phenomenon where particles from the surface gain enough energy to overcome forces of attraction and change into vapor state
Colloids
- Heterogeneous mixture with particles too small to be seen with the naked eye
- Classified according to the state of the dispersing medium and the dispersed phase
- Examples: whipped cream, fog, ink, smoke
- Properties: stable, cannot be separated by filtration, require centrifugation to separate colloidal particles
- Components: dispersed phase (solute-like component) and dispersion medium
Mixtures and Pure Substances
- Mixture: contains more than one substance mixed in any proportion
- Solution: homogeneous mixture of two or more substances with a major component (solvent) and a minor component (solute)
- Concentration of a solution: amount of solute per unit volume or mass of the solution
- Suspension: heterogeneous mixture with particles visible to the naked eye
- Pure substances can be elements or compounds
- Element: form of matter that cannot be broken down by chemical reactions into simpler substances
- Compound: substance composed of two or more different types of elements, chemically combined in a fixed proportion
Particles of Matter
- Particles of matter possess kinetic energy, which increases with temperature.
- As temperature rises, particles move faster.
- Particles of matter intermix on their own, a process called diffusion, which increases with temperature.
- Diffusion occurs when particles of two different types of matter get into the spaces between each other.
Attraction Between Particles
- Particles of matter attract each other.
- Forces of attraction between particles are maximum in solids, intermediate in liquids, and minimum in gases.
- Spaces between particles and kinetic energy of particles are minimum in solids, intermediate in liquids, and maximum in gases.
States of Matter
- Matter exists in three states: solid, liquid, and gas.
- The arrangement of particles is most ordered in solids, intermediate in liquids, and random in gases.
- States of matter are inter-convertible by changing temperature or pressure.
- Sublimation is the change of solid state directly to gaseous state without going through liquid state.
- Deposition is the change of gaseous state directly to solid state without going through liquid state.
Evaporation and Cooling
- Evaporation is a surface phenomenon where particles from the surface gain energy to overcome forces of attraction and change into the vapour state.
- Evaporation depends on surface area, temperature, humidity, and wind speed.
- Evaporation causes cooling due to the absorption of heat energy from the surroundings.
- 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.
- Latent heat of fusion is the amount of heat energy required to change 1 kg of solid into liquid at its melting point.
Examples of Evaporation
- Sprinkling water on a hot surface to cool it.
- Wearing cotton clothes in summer to cool down.
- Using a desert cooler to cool the air.
- Keeping water in an earthen pot to cool it.
- Feeling cold when applying acetone or petrol on the skin.
Measurement Units
- 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)
Concentration of a Solution
- A solution is stable, with solute particles not settling down when left undisturbed.
- Concentration of a solution can be expressed in three ways:
- Mass by mass percentage: (Mass of solute / Mass of solution) × 100
- Mass by volume percentage: (Mass of solute / Volume of solution) × 100
- Volume by volume percentage: (Volume of solute / Volume of solution) × 100
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Description
A quiz on the basics of matter and its states, including changes in states and temperature scales. Covers topics such as melting, changing states, and temperature measurements.