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All questions of Is Matter Around Us Pure for Class 9 Exam
The formation of water from oxygen and hydrogen is a _______ .- a)Physical change
- b)Chemical change
- c)Reversible change
- d)Both Physical and Reversible change
Correct answer is option 'B'. Can you explain this answer?
The formation of water from oxygen and hydrogen is a _______ .
a)
Physical change
b)
Chemical change
c)
Reversible change
d)
Both Physical and Reversible change
|
Jaideep Sharma answered |
Chemical Change:
When hydrogen and oxygen combine to form water, a new substance with different properties is formed. This is a chemical change.
Explanation:
Chemical change is a process in which one or more substances are changed into new substances with different physical and chemical properties. In the formation of water from hydrogen and oxygen, the hydrogen and oxygen molecules bond together to form a new molecule of water. This reaction is accompanied by the release of energy in the form of heat and light.
The chemical equation for the reaction is:
2H2 + O2 → 2H2O
Here, two molecules of hydrogen (H2) and one molecule of oxygen (O2) combine to form two molecules of water (H2O).
Reversible Change:
The formation of water from hydrogen and oxygen is not a reversible change. Once the reaction takes place, it is not possible to separate the water molecules back into hydrogen and oxygen.
Conclusion:
Hence, the correct option is B. Chemical change.
When hydrogen and oxygen combine to form water, a new substance with different properties is formed. This is a chemical change.
Explanation:
Chemical change is a process in which one or more substances are changed into new substances with different physical and chemical properties. In the formation of water from hydrogen and oxygen, the hydrogen and oxygen molecules bond together to form a new molecule of water. This reaction is accompanied by the release of energy in the form of heat and light.
The chemical equation for the reaction is:
2H2 + O2 → 2H2O
Here, two molecules of hydrogen (H2) and one molecule of oxygen (O2) combine to form two molecules of water (H2O).
Reversible Change:
The formation of water from hydrogen and oxygen is not a reversible change. Once the reaction takes place, it is not possible to separate the water molecules back into hydrogen and oxygen.
Conclusion:
Hence, the correct option is B. Chemical change.
A coffee filter is used to separate coffee liquid from ground, this is a suitable example for- a)sublimation
- b)distillation
- c)filtration
- d)evaporation
Correct answer is option 'C'. Can you explain this answer?
A coffee filter is used to separate coffee liquid from ground, this is a suitable example for
a)
sublimation
b)
distillation
c)
filtration
d)
evaporation
|
Hansa Sharma answered |
Filtration is any of various mechanical, physical or biological operations that separate solids from fluids (liquids or gases) by adding a medium through which only the fluid can pass. The fluid that passes through is called the filtrate
Which of the following is not a mixture? a) Soap solutionb) Bloodc) Carbon dioxided) CoalCorrect answer is option 'C'. Can you explain this answer?
|
Gaurav Kumar answered |
Carbon dioxide is not a mixture since it contain fixed ratio of oxygen and carbon in 2:1, which is a property of compound not a mixture.
Which of the following is not a pure substance?- a)Mercury
- b)Distilled water
- c)Nitric acid
- d)Tap water
Correct answer is 'D'. Can you explain this answer?
Which of the following is not a pure substance?
a)
Mercury
b)
Distilled water
c)
Nitric acid
d)
Tap water
|
Varun Kumar answered |
Tap water is not a pure substance because it is mixed with chemicals that purify it and if it was from the ground it has naturally occurring minerals mixed in it.
The separation of two immiscible liquids by a separating funnel depends upon:- a)The difference in their densities.
- b)The difference in their colours.
- c)The difference in their melting points.
- d)The difference in their boiling points
Correct answer is option 'A'. Can you explain this answer?
The separation of two immiscible liquids by a separating funnel depends upon:
a)
The difference in their densities.
b)
The difference in their colours.
c)
The difference in their melting points.
d)
The difference in their boiling points
|
Vikas Kapoor answered |
Separation by a separating funnel :
A mixture of two immiscible liquids can be separated by using a separating funnel. A separating funnel is a special type of funnel which has a stop-cock in its stem to allow the flow of a liquid from it, or to stop the flow of liquid from it. The separation of two immiscible liquids by a separating funnel depends on the difference in their densities.
A mixture of two immiscible liquids can be separated by using a separating funnel. A separating funnel is a special type of funnel which has a stop-cock in its stem to allow the flow of a liquid from it, or to stop the flow of liquid from it. The separation of two immiscible liquids by a separating funnel depends on the difference in their densities.
A desert is ...................- a)an endless stretch of sand
- b)without rainfall
- c)without vegetation
- d)all of the above
Correct answer is option 'D'. Can you explain this answer?
A desert is ...................
a)
an endless stretch of sand
b)
without rainfall
c)
without vegetation
d)
all of the above
|
Parth Nambiar answered |
Desert
Desert is a geographical region that is characterized by extreme dryness and lack of precipitation. It is a vast expanse of land that receives very little rainfall, and as a result, vegetation is scarce, and sand is abundant.
Endless stretch of sand
Deserts are often associated with endless stretches of sand dunes, but this is not always the case. While sand dunes are a common feature of many deserts, there are also rocky deserts, and deserts that are characterized by vast plains of gravel and dirt.
Without rainfall
Deserts are defined by their lack of rainfall, with many receiving less than 10 inches of rain per year. This lack of rainfall is often due to their location, such as being situated in areas that are far from oceans or other moisture sources.
Without vegetation
The extreme dryness of deserts means that vegetation is scarce, with many deserts being home to only a few types of plants that are adapted to the harsh desert environment. These plants often have specialized adaptations to help them survive in the arid conditions, such as the ability to store water in their leaves or roots.
All of the above
In conclusion, deserts are characterized by their lack of rainfall, scarcity of vegetation, and often vast stretches of sand or rocky terrain. These features make deserts some of the most inhospitable places on Earth, but they are also home to a variety of unique and fascinating plant and animal species that have adapted to the harsh desert environment.
Desert is a geographical region that is characterized by extreme dryness and lack of precipitation. It is a vast expanse of land that receives very little rainfall, and as a result, vegetation is scarce, and sand is abundant.
Endless stretch of sand
Deserts are often associated with endless stretches of sand dunes, but this is not always the case. While sand dunes are a common feature of many deserts, there are also rocky deserts, and deserts that are characterized by vast plains of gravel and dirt.
Without rainfall
Deserts are defined by their lack of rainfall, with many receiving less than 10 inches of rain per year. This lack of rainfall is often due to their location, such as being situated in areas that are far from oceans or other moisture sources.
Without vegetation
The extreme dryness of deserts means that vegetation is scarce, with many deserts being home to only a few types of plants that are adapted to the harsh desert environment. These plants often have specialized adaptations to help them survive in the arid conditions, such as the ability to store water in their leaves or roots.
All of the above
In conclusion, deserts are characterized by their lack of rainfall, scarcity of vegetation, and often vast stretches of sand or rocky terrain. These features make deserts some of the most inhospitable places on Earth, but they are also home to a variety of unique and fascinating plant and animal species that have adapted to the harsh desert environment.
A shining thick liquid is often used in glass thermometers. Name it.- a)Bromine
- b)Mercury
- c)Gallium
- d)Calcium
Correct answer is option 'B'. Can you explain this answer?
A shining thick liquid is often used in glass thermometers. Name it.
a)
Bromine
b)
Mercury
c)
Gallium
d)
Calcium
|
Ananya jain answered |
Mercury is a thick shining liquid used commonly in glass thermometer. It does not stick with wall and expands uniformly on heating.
Which of the following is a liquid metal-- a)Copper
- b)Mercury
- c)Bromine
- d)Silver
Correct answer is option 'B'. Can you explain this answer?
Which of the following is a liquid metal-
a)
Copper
b)
Mercury
c)
Bromine
d)
Silver
|
Jyoti Kapoor answered |
Mercury
Liquid metal consists of alloys with very low melting points which form a eutectic that is liquid at room temperature. The standard metal used to be mercury, but gallium-based alloys, which are lower both in their vapor pressure at room temperature and toxicity, are being used as a replacement in various applications.
What is the basic principle behind simple distillation process?- a)Sufficient difference in the boiling points of two miscible liquids and the two liquids should boil without decomposition.
- b)The two liquids should be immiscible.
- c)Difference in boiling and melting points of two miscible liquids should be less than 30°C.
- d)The two liquids should have molecular weight greater than 200 g/mol.
Correct answer is option 'A'. Can you explain this answer?
What is the basic principle behind simple distillation process?
a)
Sufficient difference in the boiling points of two miscible liquids and the two liquids should boil without decomposition.
b)
The two liquids should be immiscible.
c)
Difference in boiling and melting points of two miscible liquids should be less than 30°C.
d)
The two liquids should have molecular weight greater than 200 g/mol.
|
|
Hansa Sharma answered |
Fractional distillation is the method used for the separation of components of a mixture containing two miscible liquids that boil without decomposition and have sufficient difference in their boiling points.
Two conditions essential for using this method are:
1) Two liquids must be miscible that is they totally mix with each other.
2) The difference between the boiling points of the liquids should be greater than 25K.
Which of the following colloid is a gel?- a)Fog
- b)Cheese
- c)Milk
- d)Smoke
Correct answer is option 'B'. Can you explain this answer?
Which of the following colloid is a gel?
a)
Fog
b)
Cheese
c)
Milk
d)
Smoke
|
|
Vivek Rana answered |
The colloidal system constituting the liquid as the dispersed phase and the solid as the dispersion medium is known as gel. There are some sols that have a high concentration of dispersed solid and change spontaneously into semi solid form on cooling. These are known as gels and the process is known as gelatin
What type of mixture is obtained on continuous stirring when we add one spoon of sugar to water?- a)Homogeneous mixture
- b)Colloid
- c)Suspension
- d)Heterogeneous mixture
Correct answer is option 'A'. Can you explain this answer?
What type of mixture is obtained on continuous stirring when we add one spoon of sugar to water?
a)
Homogeneous mixture
b)
Colloid
c)
Suspension
d)
Heterogeneous mixture
|
Anita Menon answered |
The homogeneous mixture is obtained because the particles of sugar are so small that it can be diffused to the intermolecular space. The composition remains is the same throughout.
Can you explain the answer of this question below:Which of the following are chemical changes?
- A:
Freezing of water
- B:
Cooking of vegetables.
- C:
Drying of wet clothes in sun light
- D:
Melting of ice
The answer is b.
Which of the following are chemical changes?
Freezing of water
Cooking of vegetables.
Drying of wet clothes in sun light
Melting of ice
|
Divya Ahuja answered |
If the chemical composition is changing then it is a chemical change and if the chemical composition is remaining the same, then it is a physical change.
Cooking of vegetables is a chemical change because here the chemical composition of the substance changes.
The components of crude petroleum gets separated at different heights depending upon their _______ in a fractional distillation column.- a)melting points
- b)density
- c)boiling points
- d)colour
Correct answer is option 'C'. Can you explain this answer?
The components of crude petroleum gets separated at different heights depending upon their _______ in a fractional distillation column.
a)
melting points
b)
density
c)
boiling points
d)
colour
|
|
Hansa Sharma answered |
Fractional distillation is a process to separate the different components in a mixture based on the different boiling points of the components.
Inside the furnace, the oil is heated to about 400ºC, at which it vaporizes and passes up the fractionating column. The components or fractions condense and exit the column at different heights depending on their boiling points.
Inside the furnace, the oil is heated to about 400ºC, at which it vaporizes and passes up the fractionating column. The components or fractions condense and exit the column at different heights depending on their boiling points.
Which one of the following scrap metals cannot be separated by magnetic separation?- a)Steel
- b)Nickel
- c)Cobalt
- d)Chromium
Correct answer is option 'D'. Can you explain this answer?
Which one of the following scrap metals cannot be separated by magnetic separation?
a)
Steel
b)
Nickel
c)
Cobalt
d)
Chromium
|
Ravi Verma answered |
Chromium does not have magnetic properties so it cannot be separated by magnetic separation.
The smell of hydrogen sulphide (H2S) gas- a)pleasant
- b)of rotten egg
- c)of burning sulphur
- d)None of these
Correct answer is option 'B'. Can you explain this answer?
The smell of hydrogen sulphide (H2S) gas
a)
pleasant
b)
of rotten egg
c)
of burning sulphur
d)
None of these
|
Pooja Shah answered |
Hydrogen sulfide is a flammable, colorless gas with a characteristic odour of rotten eggs. It is commonly known as hydrosulfuric acid, sewer gas, and stink damp. People can smell it at low levels.
What is the correct order of the below mentioned units in water purification system?
1) Coagulation and Flocculation
2) Disinfection
3) Sedimentation tank
4) Filtration tan
- a)3, 2, 4, 1
- b)1, 2, 3, 4
- c)1, 3, 4, 2
- d)4, 3, 2, 1
Correct answer is option 'C'. Can you explain this answer?
What is the correct order of the below mentioned units in water purification system?
1) Coagulation and Flocculation
2) Disinfection
3) Sedimentation tank
4) Filtration tan
2) Disinfection
3) Sedimentation tank
4) Filtration tan
a)
3, 2, 4, 1
b)
1, 2, 3, 4
c)
1, 3, 4, 2
d)
4, 3, 2, 1
|
|
Krishna Iyer answered |
Stages of water treatment:
(i) Collection
(ii) Screening & Straining
(iii) Chemical Addition
(iv) Coagulation & Flocculation
(v) Sedimentation & Clarification
(vi) Filtration
(vii) Disinfection
(viii) Storage
(ix) Finally Distribution
Therefore, option (c) is the correct answer.
(i) Collection
(ii) Screening & Straining
(iii) Chemical Addition
(iv) Coagulation & Flocculation
(v) Sedimentation & Clarification
(vi) Filtration
(vii) Disinfection
(viii) Storage
(ix) Finally Distribution
Therefore, option (c) is the correct answer.
Which of the following involves physical change?- a)Grinding
- b)Tearing
- c)Cutting
- d)All of the above
Correct answer is option 'D'. Can you explain this answer?
Which of the following involves physical change?
a)
Grinding
b)
Tearing
c)
Cutting
d)
All of the above
|
Chinu answered |
The answer is 'D' because we can rejoin the teared or cut paper and the grind substance can also be rejoined.
If a solution contains 60g of common salt in 340g of water, the mass by mass percentage will be:- a)25 %
- b)15 %
- c)20 %
- d)17.6 %
Correct answer is 'B'. Can you explain this answer?
If a solution contains 60g of common salt in 340g of water, the mass by mass percentage will be:
a)
25 %
b)
15 %
c)
20 %
d)
17.6 %
|
|
Vivek Rana answered |
Concentration of solution is mass of solute upon mass of solution by 100 so mass of solute is 60g and mass of solvent is 340 so mass of solution is 340+60 is equal to 400 we put these values in formula so 60/400×100=15%.
Can you explain the answer of this question below:A combination of common salt and iron filings is a- A:Mixture
- B:Elements
- C:Compound
- D:both a and b
The answer is a.
A combination of common salt and iron filings is a
A:
Mixture
B:
Elements
C:
Compound
D:
both a and b
|
Prachi Rathore answered |
Here 2 substances are combined together so it is a mixture
How can we separate a mixture of sulphur and sugar?- a)By the process of filtration
- b)By the process of crystallisation
- c)By dissolving in carbon disulphide solution
- d)By evaporation
Correct answer is option 'C'. Can you explain this answer?
How can we separate a mixture of sulphur and sugar?
a)
By the process of filtration
b)
By the process of crystallisation
c)
By dissolving in carbon disulphide solution
d)
By evaporation
|
Arka Dey answered |
Distillation is a way of separating substances based on the difference in their boiling points. Using distillation it is possible to separate sugar, which has a much higher boiling point than water, from water.
Which method is used to separate cream from milk?- a)Centrifugation
- b)Adsorption
- c)Distillation
- d)Crystallization
Correct answer is option 'A'. Can you explain this answer?
Which method is used to separate cream from milk?
a)
Centrifugation
b)
Adsorption
c)
Distillation
d)
Crystallization
|
Mayank Mehta answered |
Milk is a suspension of tiny droplets of oil (cream) in a watery liquid. The process of centrifugation is used to separate cream from milk. The milk is put in a close container in big centrifuge machine. When the centrifuge machine is switched on, the milk is rotated (or spun) at a very high speed in its container. The centrifugal force acts on the milk and due to this, the milk separates into cream and skimmed milk. The cream, being lighter, floats over the skimmed milk and can then be removed.
4 g of solute are dissolved in 36 g of water. What is the mass percent of the solution?
- a)20%
- b)100%
- c)10%
- d)5%
Correct answer is option 'C'. Can you explain this answer?
4 g of solute are dissolved in 36 g of water. What is the mass percent of the solution?
a)
20%
b)
100%
c)
10%
d)
5%
|
|
Krishna Iyer answered |
Mass percent of solution = (mass of solute / mass of solution)×100%(mass of solute / mass of solution)×100%
= 4 ×100%
4+36
= 10%.
= 4 ×100%
4+36
= 10%.
A colloid with a solid dispersed phase and liquid dispersing medium is called:- a)Foam
- b)Gel
- c)Sol
- d)Emulsion
Correct answer is option 'C'. Can you explain this answer?
A colloid with a solid dispersed phase and liquid dispersing medium is called:
a)
Foam
b)
Gel
c)
Sol
d)
Emulsion
|
Vivek Kumar answered |
Because sol is a colloids in which tiny solid particles are dispersed in a liquid medium.thats why correct answer is sol
Name the solvent which is known as universal solvent.- a)Ethanol
- b)Benzene
- c)Vinegar
- d)Water
Correct answer is option 'D'. Can you explain this answer?
Name the solvent which is known as universal solvent.
a)
Ethanol
b)
Benzene
c)
Vinegar
d)
Water
|
|
Anita Menon answered |
Water is capable of dissolving a variety of different substances, which is why it is such a good solvent. And, water is called the "universal solvent" because it dissolves more substances than any other liquid. This is important to every living thing on earth. It means that wherever water goes, either through the ground or through our bodies, it takes along valuable chemicals, minerals, and nutrients.
It is water's chemical composition and physical attributes that make it such an excellent solvent. Water molecules have a polar arrangement of the oxygen and hydrogen atoms—one side (hydrogen) has a positive electrical charge and the other side (oxygen) had a negative charge. This allows the water molecule to become attracted to many other different types of molecules. Water can become so heavily attracted to a different molecule, like salt (NaCl), that it can disrupt the attractive forces that hold the sodium and chloride in the salt molecule together and, thus, dissolve it.
Most paints are:- a)Gels
- b)Suspensions
- c)Emulsions
- d)Sols
Correct answer is option 'D'. Can you explain this answer?
Most paints are:
a)
Gels
b)
Suspensions
c)
Emulsions
d)
Sols
|
Naina Sharma answered |
Most paints are sols in which tiny solid particles are dispersed in a liquid medium.
Which of the following statement is true for colloids?- a)Colloid is a homogeneous mixture.
- b)Particles of a colloid can be seen by naked eye.
- c)Particles of colloid scatter a beam of light passing through it.
- d)All of these
Correct answer is option 'C'. Can you explain this answer?
Which of the following statement is true for colloids?
a)
Colloid is a homogeneous mixture.
b)
Particles of a colloid can be seen by naked eye.
c)
Particles of colloid scatter a beam of light passing through it.
d)
All of these
|
|
Vivek Rana answered |
A starch solution is a colloidal solution. in a colloidal solution, particles are relatively big. so, when a beam of light is passed, the path of light is visible. it scatters. this scattering of beam of light through a colloidal solution is called tyndall effect.
Why do we separate ethyl alcohol and water by fractional distillation?
a) The difference in the boiling point of the liquids is less than 30°C.b) Because water is a universal solvent.c) Because both of them are liquids.d) All of the aboveCorrect answer is option 'D'. Can you explain this answer?
|
|
Mayank Raj answered |
Correct answer should be, c.
Because options no.,b.is that water is not
an universal solvent.
Options A, boiling point difference should be 30kelvin
Because options no.,b.is that water is not
an universal solvent.
Options A, boiling point difference should be 30kelvin
In fractional distillation, what is the purpose of the beads packed in column?- a)More liquid is distilled when beads are used in the column.
- b)To restrict the path of moving vapours.
- c)Beads provide surface for vapours to cool and condense repeatedly.
- d)Beads provide larger surface for heating.
Correct answer is option 'C'. Can you explain this answer?
In fractional distillation, what is the purpose of the beads packed in column?
a)
More liquid is distilled when beads are used in the column.
b)
To restrict the path of moving vapours.
c)
Beads provide surface for vapours to cool and condense repeatedly.
d)
Beads provide larger surface for heating.
|
|
Anita Menon answered |
The fractionating column is used to separate the liquids according to the order of their vaporisation so that they get separated as they are vaporised. The distillation process with fractional column is called fractional distillation and it is a special type of distillation in which two miscible liquids having two different boiling points but close to each other are separated by fractionating column .
What precaution should be taken while separating the coloured components of ink?- a)Ink should not be heated directly.
- b)Ink should be heated directly on low temperature.
- c)Ink should be heated directly on high temperature.
- d)None of the above
Correct answer is option 'A'. Can you explain this answer?
What precaution should be taken while separating the coloured components of ink?
a)
Ink should not be heated directly.
b)
Ink should be heated directly on low temperature.
c)
Ink should be heated directly on high temperature.
d)
None of the above
|
|
Ananya Sharma answered |
If ink is heated directly at high temperatures, the dye may get decomposed.
100 mL solution contains 3.5 g salt. The mass by volume percentage (m/v) of the solution is- a)3.5 %
- b)2.5 %
- c)35 %
- d)25 %
Correct answer is option 'A'. Can you explain this answer?
100 mL solution contains 3.5 g salt. The mass by volume percentage (m/v) of the solution is
a)
3.5 %
b)
2.5 %
c)
35 %
d)
25 %
|
|
Amit Sharma answered |
FORMULA FOR MASS BY VOLUME PERCENTAGE IS = TOTAL MASS OF SOLUTE / TOTAL VOLUME × 100 MASS OF SOLUTE = 3.5 G VOLUME = 100 THERE FOR 3.5G/100 ×100= 3.5 %
Heating of a sugar is a _____ change.
- a)Chemical
- b)Physical
- c)Reversible
- d)Natural
Correct answer is option 'B'. Can you explain this answer?
Heating of a sugar is a _____ change.
a)
Chemical
b)
Physical
c)
Reversible
d)
Natural
|
|
Hansa Sharma answered |
Physical Change
- It is a temporary change and affects only physical properties like shape, size, etc
- In a physical change, the composition remains the same but the change is only in the arrangement of molecules.
Reason for: Heating of sugar is a Physical change
- Sugar is composed of Carbon(C), Hydrogen (H), and Oxygen (O) atoms.
- These elements react with the fire and transform into a liquid when heated.
- The sugar atoms interact with the oxygen in the air, creating new groups of atoms as a result of the heat.
- The chemical reaction releases energy in the form of smoke and black soot.
- As a result, only the physical state changes.
Hence, due to no change in the physical state, the heating of sugar is a physical change.
An example of a colloid is:- a)Sugar solution
- b)Milk
- c)Oxygen
- d)Water
Correct answer is option 'B'. Can you explain this answer?
An example of a colloid is:
a)
Sugar solution
b)
Milk
c)
Oxygen
d)
Water
|
|
Anita Menon answered |
Types of colloids. Colloids are common in everyday life. Some examples include whipped cream, mayonnaise, milk, butter, gelatin, jelly, muddy water, plaster, colored glass, and paper. Every colloid consists of two parts: colloidal particles and the dispersing medium.
What do you understand by the term concentrated solution?- a)Solution containing no solute
- b)Solution with low solute concentration
- c)Solution in which no more solute can be dissolved
- d)Solution with high solute concentration
Correct answer is option 'D'. Can you explain this answer?
What do you understand by the term concentrated solution?
a)
Solution containing no solute
b)
Solution with low solute concentration
c)
Solution in which no more solute can be dissolved
d)
Solution with high solute concentration
|
Sarita Reddy answered |
A concentrated solution contains a relatively large amount of the solute in the same volume of solvent. Most commercial acids are concentrated solutions. For example, commercial hydrochloric acid (HCl) and sulfuric acid (H2SO4) are concentrated solutions.
A dilute solution is one that contains a relatively small amount of the solute in a given volume of solvent. Tap water is an example of a dilute
solution; it contains very small quantities of dissolved minerals.
Statement A: Brass is a solution while gun powder is not
Statement B: Air represents a solution in terms of science
Which of the two statements is true
- a)Statement B
- b)Statement A
- c)Both the Statement A and B
- d)Neither Statement A nor Statement B.
Correct answer is option 'A'. Can you explain this answer?
Statement A: Brass is a solution while gun powder is not
Statement B: Air represents a solution in terms of science
Which of the two statements is true
Statement B: Air represents a solution in terms of science
Which of the two statements is true
a)
Statement B
b)
Statement A
c)
Both the Statement A and B
d)
Neither Statement A nor Statement B.
|
|
Arun Sharma answered |
Brass is a homogeneous mixture of copper and Zinc. Gun powder is not a powder is a simple mixture of saltpeter, sulfur and charcoal.
Air is an example of a solution (gaseous solution) because it is a homogeneous mixture of different gases like oxygen, nitrogen, helium, hydrogen, etc.
Air is an example of a solution (gaseous solution) because it is a homogeneous mixture of different gases like oxygen, nitrogen, helium, hydrogen, etc.
During filtration, the solid that remains on the filter paper is called:- a)Solute
- b)Residue
- c)Solvent
- d)Filtrate
Correct answer is option 'B'. Can you explain this answer?
During filtration, the solid that remains on the filter paper is called:
a)
Solute
b)
Residue
c)
Solvent
d)
Filtrate
|
|
Chinu answered |
Residue means the small amount of something remains after the main substance had gone. Thus in filtration also the solid remain is called residue.
Which one of the following statement is incorrect regarding different separation techniques?- a)Chromatography is used to separate dyes and pigments.
- b)Evaporation is used to separate components of chlorophyll.
- c)Churning technique is used for separating cream from milk.
- d)The process of evaporation is used on a large scale to obtain common salt from sea-water.
Correct answer is option 'B'. Can you explain this answer?
Which one of the following statement is incorrect regarding different separation techniques?
a)
Chromatography is used to separate dyes and pigments.
b)
Evaporation is used to separate components of chlorophyll.
c)
Churning technique is used for separating cream from milk.
d)
The process of evaporation is used on a large scale to obtain common salt from sea-water.
|
|
Hansa Sharma answered |
Evaporation is used to separate salt from seawater.
The process of separation of insoluble solids from a liquid is called:- a)Filtration
- b)Decantation
- c)Crystallisation
- d)Evaporation
Correct answer is option 'A'. Can you explain this answer?
The process of separation of insoluble solids from a liquid is called:
a)
Filtration
b)
Decantation
c)
Crystallisation
d)
Evaporation
|
|
Krishna Iyer answered |
Filtration is a method for separating an insoluble solid from a liquid. When a mixture of sand and water is filtered: the sand stays behind in the filter paper (it becomes the residue ) the water passes through the filter paper (it becomes the filtrate).
Which of the following apparatus is not required in sublimation?- a)Condenser
- b)Funnel
- c)China dish
- d)Wire gauze
Correct answer is option 'A'. Can you explain this answer?
Which of the following apparatus is not required in sublimation?
a)
Condenser
b)
Funnel
c)
China dish
d)
Wire gauze
|
|
Jyoti Kapoor answered |
Condenser is a heat exchanging device in which substances condense. They lose heat and and turn into liquid from gaseous state.
Which of the following substances will not dissolve in water?- a)Sugar
- b)Sodium chloride
- c)Copper sulphate
- d)Carbon
Correct answer is option 'D'. Can you explain this answer?
Which of the following substances will not dissolve in water?
a)
Sugar
b)
Sodium chloride
c)
Copper sulphate
d)
Carbon
|
|
Amit Sharma answered |
A molecule of carbon dioxide has a slight negative charge near the oxygen and a slight positive charge near the carbon. CO2 is soluble because water molecules are attracted to these polar areas. The bond between carbon and oxygen is not as polar as the bond between hydrogen and oxygen, but it is polar enough that carbon dioxide can dissolve in water.
Which of the following statements is incorrect about physical changes?- a)There is no gain or loss of energy.
- b)It is permanent and irreversible.
- c)Composition of the substance remains same.
- d)No new substance is formed.
Correct answer is option 'B'. Can you explain this answer?
Which of the following statements is incorrect about physical changes?
a)
There is no gain or loss of energy.
b)
It is permanent and irreversible.
c)
Composition of the substance remains same.
d)
No new substance is formed.
|
|
Gopal Majumdar answered |
Explanation:
Physical changes are changes in the physical properties of a substance, such as shape, size, state, or appearance. They do not involve any change in the chemical composition of the substance. Some common examples of physical changes are melting, freezing, boiling, condensation, sublimation, and dissolution.
Now, let us analyze the given statements one by one:
a) There is no gain or loss of energy: This statement is correct. Physical changes do not involve any change in the energy of the substance. The energy may be required to carry out the change, but it is not gained or lost by the substance itself.
b) It is permanent and irreversible: This statement is incorrect. Physical changes are usually temporary and reversible. For example, if we melt an ice cube, it will turn into water, but we can freeze the water again to get back the ice cube. Similarly, if we dissolve salt in water, we can evaporate the water to get back the salt.
c) Composition of the substance remains the same: This statement is correct. Physical changes do not involve any change in the chemical composition of the substance. The atoms or molecules of the substance remain the same before and after the change.
d) No new substance is formed: This statement is correct. Physical changes do not involve any chemical reaction, so no new substance is formed. The substance may change its state or appearance, but it remains the same substance.
Therefore, the correct answer is option 'B' which says that physical changes are permanent and irreversible. In reality, physical changes are usually temporary and reversible.
Physical changes are changes in the physical properties of a substance, such as shape, size, state, or appearance. They do not involve any change in the chemical composition of the substance. Some common examples of physical changes are melting, freezing, boiling, condensation, sublimation, and dissolution.
Now, let us analyze the given statements one by one:
a) There is no gain or loss of energy: This statement is correct. Physical changes do not involve any change in the energy of the substance. The energy may be required to carry out the change, but it is not gained or lost by the substance itself.
b) It is permanent and irreversible: This statement is incorrect. Physical changes are usually temporary and reversible. For example, if we melt an ice cube, it will turn into water, but we can freeze the water again to get back the ice cube. Similarly, if we dissolve salt in water, we can evaporate the water to get back the salt.
c) Composition of the substance remains the same: This statement is correct. Physical changes do not involve any change in the chemical composition of the substance. The atoms or molecules of the substance remain the same before and after the change.
d) No new substance is formed: This statement is correct. Physical changes do not involve any chemical reaction, so no new substance is formed. The substance may change its state or appearance, but it remains the same substance.
Therefore, the correct answer is option 'B' which says that physical changes are permanent and irreversible. In reality, physical changes are usually temporary and reversible.
Which technique is used in diagnostic laboratories for blood and urine test?- a)Sublimation
- b)Centrifugation
- c)Evaporation
- d)Magnetic separation
Correct answer is option 'B'. Can you explain this answer?
Which technique is used in diagnostic laboratories for blood and urine test?
a)
Sublimation
b)
Centrifugation
c)
Evaporation
d)
Magnetic separation
|
Nikhil Mehra answered |
Centrifugation is a technique used in diagnostic labs for blood and urine tests.The principle of centrifugation is that denser particles are forced to the bottom and the lighter particles float on the surface.
Which of the following statement is correct?- a)Both burning of a paper and cooking of food are examples of a physical change
- b)Both burning of wood and cooking of food are are examples of a chemical change.
- c)Burning of a paper is a physical change and cooking of food is a chemical change.
- d)Burning of a paper is chemical change and cooking of food is a physical change.
Correct answer is option 'B'. Can you explain this answer?
Which of the following statement is correct?
a)
Both burning of a paper and cooking of food are examples of a physical change
b)
Both burning of wood and cooking of food are are examples of a chemical change.
c)
Burning of a paper is a physical change and cooking of food is a chemical change.
d)
Burning of a paper is chemical change and cooking of food is a physical change.
|
|
Avinash Patel answered |
Examples of Chemical Changes
A new compound (product) results from a chemical change as the atoms rearrange themselves to form new chemical bonds.
A new compound (product) results from a chemical change as the atoms rearrange themselves to form new chemical bonds.
- Burning wood
- Souring milk
- Mixing acid and base
- Digesting food
- Cooking an egg
- Heating sugar to form caramel
- Baking a cake
- Rusting of iron
Air shows the property of- a)N2
- b)O2
- c)Both (a) and (b)
- d)None of these.
Correct answer is option 'C'. Can you explain this answer?
Air shows the property of
a)
N2
b)
O2
c)
Both (a) and (b)
d)
None of these.
|
|
Niharika reddy answered |
Air is a mixture of gases consisting of approximately 4/5 Nitrogen and 1/5 Oxygen.
Which of the following method can be used to separate a mixture of camphor and sugar?- a)Sublimation
- b)Filtration
- c)Distillation
- d)Crystallisation
Correct answer is option 'A'. Can you explain this answer?
Which of the following method can be used to separate a mixture of camphor and sugar?
a)
Sublimation
b)
Filtration
c)
Distillation
d)
Crystallisation
|
|
Arun Sharma answered |
Sublimation is the process which is used to separate the mixture of camphor and salt. Camphor gets directly converted to its gaseous state, leaving the salt behind.
Which technique is used to separate blood cells from plasma?- a)Evaporation
- b)Sublimation
- c)Centrifugation
- d)Filtration
Correct answer is option 'C'. Can you explain this answer?
Which technique is used to separate blood cells from plasma?
a)
Evaporation
b)
Sublimation
c)
Centrifugation
d)
Filtration
|
|
Pratiksha Choudhary answered |
Centrifugation is a technique used to separate blood cells from plasma.
Explanation:
Centrifugation is the process of spinning a mixture at high speeds in order to separate the components based on their density. In the case of blood, the heavier blood cells are separated from the lighter plasma.
Steps of Centrifugation:
The following steps are involved in the centrifugation technique of separating blood cells from plasma:
1. Collection of blood: A sample of blood is collected from the patient in a tube containing an anticoagulant to prevent the blood from clotting.
2. Preparation of the sample: The tube is then centrifuged at high speed for a few minutes.
3. Separation of components: During centrifugation, the heavier blood cells settle at the bottom of the tube, while the lighter plasma remains on top.
4. Removal of plasma: The plasma is carefully removed from the top of the tube using a pipette or syringe.
5. Collection of cells: The remaining blood cells at the bottom of the tube can be collected for further analysis or discarded.
Advantages of Centrifugation:
Some advantages of centrifugation as a separation technique are:
1. High precision: Centrifugation is a very precise technique that can separate components with very similar densities.
2. Speed: Centrifugation is a very fast technique that can separate components in a matter of minutes.
3. Non-invasive: Centrifugation is a non-invasive technique that does not require any chemical reactions or other invasive procedures.
Conclusion:
Centrifugation is a very useful technique for separating blood cells from plasma. It is a fast, precise, and non-invasive technique that can be used in clinical settings to diagnose a wide range of medical conditions.
Explanation:
Centrifugation is the process of spinning a mixture at high speeds in order to separate the components based on their density. In the case of blood, the heavier blood cells are separated from the lighter plasma.
Steps of Centrifugation:
The following steps are involved in the centrifugation technique of separating blood cells from plasma:
1. Collection of blood: A sample of blood is collected from the patient in a tube containing an anticoagulant to prevent the blood from clotting.
2. Preparation of the sample: The tube is then centrifuged at high speed for a few minutes.
3. Separation of components: During centrifugation, the heavier blood cells settle at the bottom of the tube, while the lighter plasma remains on top.
4. Removal of plasma: The plasma is carefully removed from the top of the tube using a pipette or syringe.
5. Collection of cells: The remaining blood cells at the bottom of the tube can be collected for further analysis or discarded.
Advantages of Centrifugation:
Some advantages of centrifugation as a separation technique are:
1. High precision: Centrifugation is a very precise technique that can separate components with very similar densities.
2. Speed: Centrifugation is a very fast technique that can separate components in a matter of minutes.
3. Non-invasive: Centrifugation is a non-invasive technique that does not require any chemical reactions or other invasive procedures.
Conclusion:
Centrifugation is a very useful technique for separating blood cells from plasma. It is a fast, precise, and non-invasive technique that can be used in clinical settings to diagnose a wide range of medical conditions.
Which of the following statement is not true?- a)The solubility of gases in liquids decreases on increasing the temperature.
- b)The solubility of solids in liquids remain unaffected by changes in pressure.
- c)The solubility of solids in liquids increases on increasing the temperature.
- d)The solubility of gases in liquids increases on increasing the temperature.
Correct answer is option 'D'. Can you explain this answer?
Which of the following statement is not true?
a)
The solubility of gases in liquids decreases on increasing the temperature.
b)
The solubility of solids in liquids remain unaffected by changes in pressure.
c)
The solubility of solids in liquids increases on increasing the temperature.
d)
The solubility of gases in liquids increases on increasing the temperature.
|
|
Jyoti Kapoor answered |
The reason for this gas solubility relationship with temperature is very similar to the reason that vapor pressure increases with temperature. Increased temperature causes an increase in kinetic energy. The higher kinetic energy causes more motion in molecules which break intermolecular bonds and escape from solution. As the temperature increases, the solubility of a gas decreases.
Match the following with correct response. 
- a)1-C, 2-B, 3-D, 4-A
- b)1-A, 2-C, 3-B, 4-D
- c)1-D, 2-A, 3-C, 4-B
- d)1-B, 2-D, 3-A, 4-C
Correct answer is option 'C'. Can you explain this answer?
Match the following with correct response.
a)
1-C, 2-B, 3-D, 4-A
b)
1-A, 2-C, 3-B, 4-D
c)
1-D, 2-A, 3-C, 4-B
d)
1-B, 2-D, 3-A, 4-C
|
|
Pooja Shah answered |
Mixtures are one product of mechanically blending or mixing chemical substances such as elements and compounds, without chemical bonding or other chemical change, so that each ingredient substance retains its own chemical properties and makeup.
A chemical compound is a substance composed of two or more different elements chemically bonded together in a fixed proportion by mass. However, not all molecules are compounds. Compounds are pure substances that contain two or more elements combined in a definite fixed proportion.
Any substance that contains only one kind of an atom is known as an element. Because atoms cannot be created or destroyed in a chemical reaction, elements such as phosphorus (P4) or sulfur (S8) cannot be broken down into simpler substances by these reactions.
When a molecule is formed from elements of a different species it is a heteroatomic molecule. As an atom is the smallest particle of an element that retains the properties of that element, a molecule is the smallest particle of a compound.
A chemical compound is a substance composed of two or more different elements chemically bonded together in a fixed proportion by mass. However, not all molecules are compounds. Compounds are pure substances that contain two or more elements combined in a definite fixed proportion.
Any substance that contains only one kind of an atom is known as an element. Because atoms cannot be created or destroyed in a chemical reaction, elements such as phosphorus (P4) or sulfur (S8) cannot be broken down into simpler substances by these reactions.
When a molecule is formed from elements of a different species it is a heteroatomic molecule. As an atom is the smallest particle of an element that retains the properties of that element, a molecule is the smallest particle of a compound.
A compound is a _______ substance made up of _______ .- a)impure; two or more simpler substances
- b)soft; only one kind of atoms
- c)hard; only one element
- d)pure; two or more elements
Correct answer is option 'D'. Can you explain this answer?
A compound is a _______ substance made up of _______ .
a)
impure; two or more simpler substances
b)
soft; only one kind of atoms
c)
hard; only one element
d)
pure; two or more elements
|
|
Ananya Sharma answered |
A molecule is the smallest particle of a substance that exists independently. Molecules of most elements are made up of only one of atom of that element. Oxygen, along with nitrogen, hydrogen, and chlorine are made up of two atoms.
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