kalakadu.com: Matter Around Us Class 9th Science Tamilnadu Board Solution

Matter Around Us Class 9th Science Tamilnadu Board Solution

Class 9^th Science Tamilnadu Board Solution

Exercise-1 Multiple Choice Questions
The physical state of water at 373 K is _______A. Solid B. liquid C. vapour D.…
Among the following _ is a mixtureA. Common Salt B. Juice C. Carbon dioxide D.…
When we mix a drop of ink in water we get a _A. Heterogeneous Mixture B.…
The constituents that form a mixture are also calledA. Elements B. Compounds C. Alloys D.…
has the same properties throughout the sampleA. Pure substance B. Mixture C.…
Exercise-2 Multiple Choice Questions
The difference in _ is the principle used in fractional distillationA. solubility B.…
The separation of denser particles from lighter particles done by rotation at high speed…
_ is essential to perform separation by solvent extraction method.A. Separating…
Filtration method is effective in separating _ mixtureA. Solid-solid B.…
For a simple distillation process, we need to haveA. an evaporating dish. B. a separating…
Exercise-2 True Or False
Butter from curd can be separated by centrifugation.
Oil and water are immiscible in each other.
Sublimation is the property of a substance to directly change from liquid to solid state.…
Liquid-liquid colloids are called gels.
Fractional distillation is used when the boiling point of the components have large…
Exercise-2 Match The Following
Match the following:
Exercise-2 Fill In The Blanks
Alcohol can be separated from water by
Sand is removed from naphthalene by _ method.
In petroleum refining, the method of separation used is _…
Chromatography is based on the principle of _
The solubility of solid in water _ with an increase in temperature…
Exercise-2 Very Short Answer Type
Name the method you would adopt to separate a mixture of ammonium chloride and common…
Define a solute and a solvent.
Name the sublimate that you will be getting when you heat a mixture of i. Iodine and sand…
What is meant by desalination of sea water?
Exercise-2 Short Answer Type
What is an adsorbate and adsorbent?
What is meant by Rf value?
Differentiate between filtrate and distillate.
Name the apparatus that you will use to separate the components of mixtures containing…
How will you separate a mixture containing saw dust, naphthalene and iron filings?…
Exercise-2 Long Answer Type
How is a mixture of common salt, oil and water separated? You can use a combination of…
Group activity (group of four): Use your research skills (including the Internet) to find…
Field Trip: Visit a milk dairy and note down the at least two separating techniques used…
Exercise-2 Hots
Two immiscible liquids are taken in the above funnel for separation. Which is denser, X or…
The most appropriate labelling of X and Y in a filtration set up are…
Exercise-1 True Or False
State whether the following statements are true or false. If false give the correct…
Exercise-1 Match The Following
Match the following:
Exercise-1 Fill In The Blanks
Evaporation is always accompanied by_ in temperature
150°C = K
A _mixture has no distinguishable boundary between its components.…
An example of a substance that sublimes is
Latent heat is the energy used for ____.
Exercise-1 Very Short Answer Type
Why is it possible to row a boat in water but not pass through a wooden fence?…
How gaseous pressure arises?
Define Sublimation.
Which state of matter has the highest kinetic energy?
A few drops of ‘Dettol’ when added to water the mixture turns turbid. Why?…
Exercise-1 Short Answer Type
Why are gases easily compressible whereas solids are incompressible?…
Hold a ‘smiley ball’ and squeeze it. Can you compress it? Justify your answer?…
Which of the following are pure substances? Ice, Milk, Iron, Hydrochloric acid, Mercury,…
Oxygen is very essential for us to live. It forms 21% of air by volume. Is it an element…
You have just won a medal made of 22-carat gold. Have you just procured a pure substance…
Exercise-1 Long Answer Type
Write the differences between elements and compounds and give an example for each.…
Explain Tyndall effect and Brownian movement with suitable diagram.…
How are homogenous solutions different from heterogeneous solution? Explain with examples.…
Exercise-1 Get Together And Do
ProjectMake a model to demonstrate any characteristic property of particles in a solid,…
Exercise-1 Hots
Fill in the numbered blanks to make the heating curve meaningful.…
‘Shake well before use’. This is the instruction on a bottle of medicine. What kind of a…
What produces more severe burns, boiling water or steam? Why?

Exercise-1 Multiple Choice Questions

Question 1.
The physical state of water at 373 K is _______
A. Solid

B. liquid

C. vapour

D. plasma

Answer:
373K is equivalent to 100°C in celsius scale which is the boiling point of water so water takes in the latent heat of vaporisation at 373K and converts itself to gas(vapour) state.

Question 2.
Among the following _ is a mixture
A. Common Salt

B. Juice

C. Carbon dioxide

D. Pure Silver

Answer:
Common salt, carbon dioxide and Pure silver are pure substances while juice is mixture of water, sugar, fruits and other ingredients. Another way of identifying is that, mixture do not have any formula, here we see that juice does not have any fixed formula while others have.

Question 3.
When we mix a drop of ink in water we get a _
A. Heterogeneous Mixture

B. Homogeneous Mixture

C. Compound

D. Suspension

Answer:
Ink does not dissolve into water uniformly and mixture has different composition at different point.

Question 4.
The constituents that form a mixture are also called
A. Elements

B. Compounds

C. Alloys

D. Components

Answer:
The constituents of the mixture are also known as components of the mixture.

Question 5.
____ has the same properties throughout the sample
A. Pure substance

B. Mixture

C. Colloid

D. Suspension

Answer:
Apart from pure substances, others have different ratio of elements as we move across that thing so they have different properties at different position while pure substances have same composition everywhere.

Exercise-2 Multiple Choice Questions

Question 1.
The difference in ___ is the principle used in fractional distillation
A. solubility

B. melting point

C. boiling point

D. adsorption

Answer:
.

Question 2.
The separation of denser particles from lighter particles done by rotation at high speed is called
A. Filtration

B. sedimentation

C. decantation

D. centrifugation

Answer:
.

Question 3.
_ is essential to perform separation by solvent extraction method.
A. Separating funnel

B. centrifuge machine

C. filter paper

D. sieve

Answer:
.

Question 4.
Filtration method is effective in separating _______ mixture
A. Solid-solid

B. solid-liquid

C. liquid-liquid

D. liquid-gas

Answer:
.

Question 5.
For a simple distillation process, we need to have
A. an evaporating dish.

B. a separating funnel.

C. a filter with filter paper.

D. a Liebig condenser.

Answer:
.

Exercise-2 True Or False

Question 1.
Butter from curd can be separated by centrifugation.

Answer:
False

Butter from milk can be separated by centrifugation.

Question 2.
Oil and water are immiscible in each other.

Answer:
True

Question 3.
Sublimation is the property of a substance to directly change from liquid to solid state.

Answer:
True

Question 4.
Liquid-liquid colloids are called gels.

Answer:
False
Liquid – liquid colloids are called emulsions.

Question 5.
Fractional distillation is used when the boiling point of the components have large difference

Answer:
True

Exercise-2 Match The Following

Question 1.
Match the following:

Answer:

Exercise-2 Fill In The Blanks

Question 1.
Alcohol can be separated from water by ____

Answer:
Alcohol can be separated from water by Fractional Distillation.

Question 2.
Sand is removed from naphthalene by _ method.

Answer:
Sand is removed from naphthalene by a Sublimation method.

Question 3.
In petroleum refining, the method of separation used is _

Answer:
In petroleum refining, the method of separation used is Fractional distillation.

Question 4.
Chromatography is based on the principle of _

Answer:
Chromatography is based on the principle of different solubility of the solute in the same solvent.

Question 5.
The solubility of solid in water _____ with an increase in temperature

Answer:
The solubility of solid in water increases with an increase in temperature.

Exercise-2 Very Short Answer Type

Question 1.
Name the method you would adopt to separate a mixture of ammonium chloride and common salt.

Answer:
Using the process of sublimation we can separate mixture of ammonium chloride and common salt since ammonium chloride sublimes on heating and changes to its vapour form while common salt does not.

Question 2.
Define a solute and a solvent.

Answer:
Solute: Substance (solid, liquid and gas) which is dissolved in another substance is known as solute.

Solvent: The substance on which solute is dissolved is solvent.

E.g in the salt solution, salt is solute and water is solvent and together they make solution.

Question 3.
Name the sublimate that you will be getting when you heat a mixture of

i. Iodine and sand

ii. Sodium chloride and ammonium chloride.

Answer:
i) Iodine since it sublimes and changes to its vapour state on heating which then can be cooled to again get back the iodine.
ii) Ammonium chloride since it t sublimes and changes to its vapour state on heating which then can be cooled to again get back the Ammonium chloride.

Question 4.
What is meant by desalination of sea water?

Answer:
Desalination of sea water implies taking out salt and other vital minerals from sea water.

Exercise-2 Short Answer Type

Question 1.
What is an adsorbate and adsorbent?

Answer:
Adsorbate: Substance which get adsorbed (atoms or ions of the substance get attached to other surface by adhesive force) on the adsorbent.
Adsorbent: Substance on whose surface substance gets adsorbed. Its concentration is high.

Question 2.
What is meant by Rf value?

Answer:
Rf is known as Retardation factor. It is helpful in chromatography.
Rf = Distance moved by the solute/Distance moved by the solvent.

Here distances are measured from the common origin.

Question 3.
Differentiate between filtrate and distillate.

Answer:

Question 4.
Name the apparatus that you will use to separate the components of mixtures containing two,

i. miscible liquids, ii. immiscible liquids.

Answer:
i) For separating miscible liquids we use fractional distillation method in which we use fractionating column (long vertical glass tube) and distillation flask.

ii) For separating immiscible liquids we use separating funnel (funnel with stop cock at its top)

Question 5.
How will you separate a mixture containing saw dust, naphthalene and iron filings?

Answer:
Mixture containing saw dust, napthalene and iron filling can be separated as follows :

a) We bring magnet near the mixture as a result iron filling get attracted to it and we are left with saw dust and napthalene.

b) Now we adopt the process of sublimation and heat the given mixture gently then napthalene sublimes which then can be collected by cooling and sand dust is left behind.

Exercise-2 Long Answer Type

Question 1.
How is a mixture of common salt, oil and water separated? You can use a combination of different methods.

Answer:
Common salt has polar nature (actually ionic) and water is a polar solvent whereas oil is non-polar so salt gets dissolved only with water. (Like dissolves like)

a) We know that oil and water are immiscible liquids and salt is dissolved only in water so we make use of separating funnel. Water along with dissolved salt is present in the lower layer while oil forms the upper layer. On opening the stop-cock, water runs out while oil remains which can then be removed.

b) Now, water boils at 100°C while common salt doesn’t so they can easily be separated with boiling or vaporisation technique.

Question 2.
Group activity (group of four): Use your research skills (including the Internet) to find out what is forensic science and obtain information about the use of chromatography in forensic science.

Answer:
Forensic science is the way of utilising science in catching the criminals in our society.

Application of chromatography in forensic science:

a) The blood samples that are recovered from the crime scene.

b) chromatography is used to analyze the explosive material.

c) It is helpful to analyze whether content written is using the same ink or different ink.

d) It is used to catch the suspect of stealing the money by mixing the money with the dye and then analyzing it using chromatography.

Question 3.
Field Trip: Visit a milk dairy and note down the at least two separating techniques used there.

Answer:
Two separating techniques used there are

a) Centrifugation : To obtain cream from raw milk. A rotating machine knowns as centrifuge is used.

b) Evaporation : After getting raw milk from farmers, it is evaporated so as to get its condensed form which is then mixed with small amount of sugar and packed in can.

Exercise-2 Hots

Question 1.

Two immiscible liquids are taken in the above funnel for separation. Which is denser, X or Y? Suggest any one example for X and one for Y. A third liquid Z which is soluble only in Y is added to the mixture and contents in the funnel are shaken well. How many layers will you observe now? How will you separate the three liquids? Boiling point of X is 98° C, that of Y is 43° C and that of Z is 75° C.

Answer:
Y is denser. One example for X is kerosene and one example for Y is water. Third liquid Z is alcohol (ethanol) which is soluble in water. We will observe two layers.

Now we will employ the process of fractional distillation since every liquid has different boiling point.

Upon taking them in fractionating column, first the liquid with least boiling point will evaporate and will be collected as pure compound and then the next one and in this we can separate all three liquids.

Question 2.
The most appropriate labelling of X and Y in a filtration set up are

Answer:
C
In the process of filtration we separate solids from the liquids in which they are insoluble. So the components that is unable to pass funnel is residue while one that has successfully passed is filtrate.

Exercise-1 True Or False

Question 1.
State whether the following statements are true or false. If false give the correct statement

(a) Liquids expand more than gases on heating.

(b) A compound cannot be broken into simpler substances chemically.

(c) Water has a definite boiling point and freezing point.

(d) Buttermilk is an example of heterogeneous mixture.

e) Aspirin is composed of 60% Carbon, 4.5% Hydrogen and 35.5% Oxygen by mass. Aspirin is a mixture.

Answer:
(a) False

Gases expand more than liquid on heating since they have more intermolecular space as compared to liquid so on heating the molecules in gases gets more space to increase in size as compared to molecules in liquid.

(b) False

Compound breaks down into simpler substance during chemical change such as when heat is supplied to calcium carbonate which is compound breaks down into simpler substances which are the constituents of it.

(c) False

The boiling point of water depends upon the surrounding pressure since at boiling point, vapour pressure of the gas coming out of the liquid equals the pressure on it because of environment. So as we move up, pressure drops as a result boiling point decreases similar is the case with melting point.

(d) True

Butter and milk are immiscible into one another and a layer of butter can be seen clearly at the top.

(e) False

Aspirin is composed of 60% Carbon, 4.5% Hydrogen and 35.5% Oxygen by mass. Aspirin is a compound.

Aspirin has fixed proportion of carbon, hydrogen and oxygen combined in the ratio of their mass. So it has fixed formula and hence it cannot be mixture as mixture has no formula.

Exercise-1 Match The Following

Question 1.
Match the following:

Answer:
i) Element –Pure substance

ii) Compound - Made up of atoms

iii) colloid – made up of molecules

iv) Suspensions - Settles down on standing

v) Mixture - Impure substance

Exercise-1 Fill In The Blanks

Question 1.
Evaporation is always accompanied by_____ in temperature

Answer:
Evaporation is always accompanied by decrease in temperature.

Question 2.
150°C = K

Answer:
150°C = 423K

Question 3.
A _mixture has no distinguishable boundary between its components.

Answer:
A Homogeneous mixture has no distinguishable boundary between its components.

Question 4.
An example of a substance that sublimes is

Answer:
An example of a substance that sublimes is camphor.

Question 5.
Latent heat is the energy used for ____.

Answer:
Latent heat is the energy used for changing state of the substance.

Exercise-1 Very Short Answer Type

Question 1.
Why is it possible to row a boat in water but not pass through a wooden fence?

Answer:
It is possible to row a boat in water as it has some spaces between its molecules so when we place boat over water, it displaces some amount of water and water displaced provides it necessary buoyant force.
Wooden fence is solid in state and has no space so it is impossible to pass through it.

Question 2.
How gaseous pressure arises?

Answer:
We know that gases have large amount of intermolecular spaces and they move freely in random direction so when we fill any container with gas then the gas molecules collides with the wall of the container and apply some force on the wall of the container and in this way gases exert pressure on the container.

Question 3.
Define Sublimation.

Answer:
Sublimation is the process in which solid directly changes to its gaseous state upon heating without passing through its liquid state.

Question 4.
Which state of matter has the highest kinetic energy?

Answer:
Gaseous/Vapour state has the highest kinetic energy since in this state the intermolecular space is more and molecules have lots of space to move and since kinetic energy is due to the movement/motion of the particles, hence it has highest kinetic energy.

Question 5.
A few drops of ‘Dettol’ when added to water the mixture turns turbid. Why?

Answer:
Turbid means Cloudiness. Dettol and water are immiscible with one another and form emulsion so when we mix them dettol particles get suspended in water and scatter white light . Therefore it appears turbid.

Exercise-1 Short Answer Type

Question 1.
Why are gases easily compressible whereas solids are incompressible?

Answer:
Gases are easily compressible since they have lot of spaces between its molecules (intermolecular space) so when we apply pressure during compressing, the molecules gets room to move from its original position while in case of solids, molecules are very close to each other and have almost no intermolecular space to move when we apply pressure on them.

Question 2.
Hold a ‘smiley ball’ and squeeze it. Can you compress it? Justify your answer?

Answer:
Yes, we can compress it. We know that smiley ball is solid in state yet it can be compressed since it has tiny pores in it, in which air resides so when we squeeze it, air is driven out and in this way we are able to compress it.

Question 3.
Which of the following are pure substances? Ice, Milk, Iron, Hydrochloric acid, Mercury, Brick and Water.

Answer:
Hydrochloric acid, mercury, Ice, Iron and Water are pure substances since they are made up of one or more than one atom of its kind. Also they have their fixed formula while in case of milk (mixture of butter, milk and other ingredients) and brick (mixture of clay, sand etc), they are made by mixing ingredients whose ratio is not fixed. Also they do not have fixed chemical formula.

Question 4.
Oxygen is very essential for us to live. It forms 21% of air by volume. Is it an element or compound?

Answer:
An element has fixed symbol and is made up of only one atom of its kind. Since Oxygen has fixed symbol (O₂) and is made up of only one atom of its kind (2 O merge together to form oxygen) it is an example of element.

Question 5.
You have just won a medal made of 22-carat gold. Have you just procured a pure substance or impure substance?

Answer:
It is an impure substance since the purity of gold is measured in terms of carat. 24 carat is the pure form of gold so 22 carat gold = (22/24) ×100 = is 91.66 % pure only. It is actually alloy of gold, silver and nickel.

Exercise-1 Long Answer Type

Question 1.
Write the differences between elements and compounds and give an example for each.

Answer:

Question 2.
Explain Tyndall effect and Brownian movement with suitable diagram.

Answer:
Tyndall effect : It is the effect in which the light is scattered due to colloidal particles in its path as a result path of light becomes visible.

In the figure shown above, the first solution is plain water which does not exhibit Tyndall effect while the second one is a colloidal solution which shows Tyndall effect as the path inside it becomes visible due to scattering of the light by the colloidal particle.

Brownian Motion: Upon dropping some tiny particles in the fluid and observing it with a microscope, we see the zig-zag movement of the particles which occurs due to the collision with the particles of the fluid. This phenomenon is known as

Brownian movement of the particles. Below figure depicts the erratic movement of the particles inside the fluid.

Question 3.
How are homogenous solutions different from heterogeneous solution? Explain with examples.

Answer:

Exercise-1 Get Together And Do

Question 1.
Project

Make a model to demonstrate any characteristic property of particles in a solid, liquid and gas.

Answer:
Model described below describes one of the important characteristics of the particles in a solid, liquid and gas.
Steps :

a) Take a beaker filled with more than half of water.

b) Put some copper sulphate at the bottom of the beaker.

c) Keep it for some time.

Observation :

After few minutes, we notice that whole solution turned blue.

Reason :

Initially, copper sulphate was placed at the bottom of the beaker. Particles of the copper sulphate start moving randomly in all direction and collide with the water particles since water particles are colourless and copper sulphate is blue in color so the particles of the copper sulphate imparts blue color to the whole solution.

Conclusion:

Particles of solid, liquid and gas are constantly moving.

Exercise-1 Hots

Question 1.
Fill in the numbered blanks to make the heating curve meaningful.

Answer:

Question 2.
‘Shake well before use’. This is the instruction on a bottle of medicine. What kind of a mixture is contained in the bottle? Give reason.

Answer:
Bottle of the medicine such as cough syrup is colloidal mixture that comes under category of emulsion in which liquids immiscible with one another are taken together.
It is advised to shake the contents of the bottle as particles inside the bottle settle down after sometime so in order to mix well the particle thoroughly so that its composition becomes same throughout.

Question 3.
What produces more severe burns, boiling water or steam? Why?

Answer:
Steam produces more severe burns as compared to boiling water.
Reason: We know that water boils at 100°C and for converting to steam at 100°C it takes the latent heat of vaporization so steam has more heat than boiling water which is the latent heat which causes more severe burns than boiling water.