Given below are the Class 9 Science Is matter around us pure extra questions with answers. These are important questions to prepare for examinationIt has below type to practice and excel in examination
(a) 1 Mark Questions
(b) Very Short questions
(c) Short questions
(d) Numericals Based on Concentration
(e) Long Anwer questions
(f) Crossword Puzzl
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1 Mark Questions
Question 1.
Salt can be recovered from its solution by evaporation. Can you suggest any other technique also? Solution
Crystallisation method.
Question 2. Each Part Carry 1 Marks
Non-metals are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non-malleable and are coloured.
a.Name a lustrous non-metal.
b.Name a non-metal which exists as a liquid at room temperature.
c.The allotropic form of a non – metal is a good conductor of electricity. Name the allotrope.
d.Name a non-metal which is known to form the largest number of compounds.
e.Name a non-metal other than carbon which shows allotrophy.
f.Name a non-metal which is required for combustion. Solution
(a) Iodine is a lustrous non-metal.
(b) Bromine is a non-metal which exists as a liquid at room temperature.
(c) Graphite is the allotropic form of carbon and it is a good conductor of electricity.
(d) Carbon is a non-metal which is known to form the largest number of compounds.
(e) Phosphorus is a non-metal other than carbon which shows allotropy.
(f) Oxygen is a non-metal which is required for combustion.
Question 3. Each Part Carry 1 Marks
Name the appropriate methods to separate the following:
a.Nitrogen from air
b.Dye from blue ink
c.Butter cream from milk
d.Ammonium chloride from common salt Solution
a. Fractional distillation
b. Process of evaporation
c. Process of centrifugation
d. sublimation
Question 4. Each Part Carry 1 Marks
Identify the physical and chemical changes from the following:
(i) Heating the mixture of iron and sulphur
(ii) Ripening of fruits
(iii) Dissolution of salt in water(iv) Rusting of iron – chair
(v) Making egg omelets Solution
i) Chemical change
ii) Chemical change
iii) Physical change
iv) Chemical change
v) Chemical change
Question 5. Each Part Carry 1 Marks
Classify the following into physical or chemical change:
(i) Burning of a candle
(ii) Freezing of water
(iii) Mixing of iron filings and sand
(iv) Fading of clothes Solution
i. Physical and chemical change both
ii. Physical change
iii. Physical change
iv. Chemical change
Question 6. Each Part Carry 1 Marks
(a) Name the separation technique you would follow to separate
(i) Dyes from black ink.
(ii) A mixture of salt and ammonium chloride
(iii) Cream from milk
(iv) Sodium chloride from its solution in water
(b) State the principle used in separating a mixture of two immiscible liquids. Solution
a) i)chromatography
ii)sublimation
iii)centrifugation
iv) evaporation
Question 7.Each Part Carry 1 Marks
Give an example for each of following:
a)Solid -liquid homogeneous mixture
b)Gas- gas homogeneous mixture
c)Liquid -liquid heterogeneous misture Solution
a) salt in water
b) Air
c) Water and oil
Very Short Answers questions
Question 1.
State any one difference between pure and impure substances. Solution
The constituents, which make up a pure substance cannot be separated by physical means
The constituents of an impure substance can be separated by physical means.
Question 2.
What is meant by concentration of a solution? Solution
The concentration of a solution is the amount of solute present per unit volume or per unit massof the solution or solvent.
Question 3.
List the two conditions essential for using distillation as a method for separation of the components from a mixture. Solution
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 less than 25k.
Question 4.
Smoke and fog both are aerosols. In what way are they different? Solution
They differ by their composition. They both are colloidal mixtures but smoke is consists of air mixed with carbon particles but fog consists of air mixed with water vapour ( mostly).
Question 5.
What do you understand by the statement 'the solubility of NaCl is 36.5 g at room temperature'? Solution
It means that, at room temperature 36.5 g of Nacl can be dissolved in 100 g (or 100 ml) of water.
Question 6
What is tincture of iodine? Identify the solute and solvent in it. Solution
Tincture of iodine means the solution of iodine and alcohol.The solute is iodine and solvent is alcohol.
Question 7.
Can we separate alcohol dissolved in water by using a separating funnel? If yes, then describe the procedure. Of not, explain. Solution
No, being miscible they cannot be separated by using a separating funnel.
Question 8.
Crystallization is a better technique than sample evaporation. Give one reason to justify the statement. Solution
Crystallization is better than evaporation in mainly two ways :
1. In evaporation, the solution needs to be at the boiling point of the solvent, the whole time. This may degrade the solute.
2. In crystallization, the crystals automatically throw away impurities to arrange themselves in a regular manner. Therefore, the degree of purity is higher than the solute left after evaporation.
Element as a basic form of matter that cannot be broken down into simpler substances by chemical reactions.
Question 10.
What are metalloids? Give two examples. Solution
Metalloid, a chemical element with properties intermediate between those of typical metals and nonmetals. Usually considered under this classification are the chemical elements boron, silicon, germanium, arsenic, antimony, and tellurium
Question 11.
Classify the following as metals, non-metals and metalloids:
Copper, silicon, carbon, chlorine, gold, boron.two non – metals from the following elements: Solution
Copper,Gold :Metal
Silicon,Boron: Metalloids
Carbon,Chlorine: Non metals
Question 12.
(a) Identify two non – metals from the following elements:
Carbon, Sodium, Chlorine, Neon, Platinum
(b) Name the appropriate method to separate nitrogen from air.
(c) Identify dispersed phase and dispersion medium in foam and rubber. Solution
a.Carbon,Chlorine: Non metals
b.Fractional distillation
c. Dispersion phase is Gas and dispersion medium is solid
1. elements
2. Compounds
3. homogenous
3. hetrogenous
Short Answers questions
Question 1.
How Tyndall effect can be observed in the canopy of a dense forest. Solution
Tyndall effect refers to the process by which light is scattered by colloids or suspension making the path of the light to be visible.
In the forests, the air contains mists which acts as the colloids hence when light seeps in through the canopy one clear sees its path.
Question 2.
How do solultion and gel differ from each other? Give one example for each. Question 3.
'Sea water can be classified as homogeneous as well as heterogeneous mixture.' Comment. Question 4.
Explain why particles of a colloidal solution do not settle down when left undisturbed, while in the case of a suspension they do. Question 5.
Mention in tabular form any two differences between heterogeneous and homogeneous mixtures. Question 6.
What are aerosols? Give any two examples. Question 7.
What is meant by an aqueous and non-aqueous solutions? Give one example of each. Question 8.
What is a solution? Write two examples. Question 9.
When is a solution said to be saturated? How can you change an unsaturated solution to a saturated solution without adding any more solvent to it? Question 10.
Smoke and fog are aerosols. How do they differ from each other? Question 11.
What is Tyndall effect? Why the solution of copper sulphate does not show Tyndall effect? Solution
Tyndall effect refers to the process by which light is scattered by colloids or suspension making the path of the light to be visible
Copper sulphate when dissolves in water forms a true solution. True solution does not show tyndall effect.
Question 12.
You are provided with solution of substance ‘X’. how will you test whether it is saturated or unsaturated with respect to ‘X’ at a given temperature? What happens when a hot saturated solution is allowed to cool? Question 13.
What is chromatography? Mention its two applications. Solution
Chromatography is a method used to separate mixture that comprises solutes that dissolve in the same solvent.This method gets its name from the Greek word for colour -Kroma, as it was first used for separating colours.
Principle: Chromatography is based on differential affinities of compounds towards two phases, i.e stationary and mobile phase.
The fraction with greater affinity towards stationary phase travels shorter distance while the fraction with less affinity towards stationary phase travels longer distance.
Chromatography is used for separating colors in a dye, pigments from natural colors and drugs from blood.
Question 14.
Draw a flow diagram showing the process of obtaining gases from air. Solution
Question 15.
State the separation technique used for the separation of the following:
a.Ammonium chloride from a mixture containing sodium chloride and ammonium chloride
b.Copper sulphate from its solution in water. Solution
a. Sublimation
b. Crystallisation
Question 16.
Classify the substances given in below figure into elements and compounds Solution
Question 17.
Define solubility. How does solubility. How does solubility of a solid in water change with temperature? Solution
Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a solution of the solute in the solvent.
For many solids dissolved in liquid water, the solubility increases with temperature. The increase in kinetic energy that comes with higher temperatures allows the solvent molecules to more effectively break apart the solute molecules that are held together by intermolecular attractions.
Question 18.
Two students A and B were given 10 ml of water in a bowl and a plate respectively. They were told to observe the rate of evaporation. Name the student whose water evaporates faster and explain its reason. Solution
Student B water will evaporates faster as it has bigger surface area
Question 19.
Why the inter-conversion of states of matter is considered as a physical change? Give three reasons to justify your answer. Question 20.
‘Colloidal solution appears to be homogeneous but actually it is heterogeneous.’ Give justification for this statement. Question 21.
When a fine beam of light enters a room through a small hole, Tyndall effect is observed. Why does this happen? Give one more example where this effect can be observed. Question 22.
With the help of a flow diagram, show the process of obtaining different gases from air. if the boiling point of oxygen, argon and nitrogen are 183° C, - 186° C and - 196° C respectively, which gas gets liquefied first as the air is cooled? Solution
Since Oxygen has the highest boiling point,it get get liquiefied first as the air is cooled
Question 23.
List three differences between a physical change and a chemical change. Solution
Physical Change
Chemical Change
The chemical composition of a substance does not change.
Change is only in the state of matter and not in the chemical identity
The chemical composition of a substance changes.
Change is in chemical identity, but may or may not be in the state of matter.
Most changes are reversible
Most changes are irreversible.
No new substances are formed. For example,
Ice → Water → Steam
New substances are formed.For example,
methane → carbon dioxide and water (on heating)
Question 24.
Differentiate between, an element and a compound (any two points) with one example each. Solution
Question 25.
(i) Name the compound formed on heating a mixture of iron filings and sulphur.
(ii) If dilute HCI is added to above compound then name the gas evolved and write down its two properties. Solution
i. Iron Sulphide(FeS)
ii. $FeS + 2HCL \rightarrow FeCl_2 + H_2S$
Question 26.
State any three differences between a mixture and a compound. Solution
Question 27.
How will you separate a mixture of common salt, camphor and iron filings .Describe the process.
Numericals
Question 1.
How many litres of 15% (mass/ volume) sugar solution would it take to get 75 g of sugar? Solution
We want a liquid which has 15% sugar as it's concentration.
Let the volume be x
Now Concentration% = Mass of the solute/Volume of the solution
15% =75/x
x=500ml =.5 l
Question 2.
A solution contains 40 g of common salt in 320 g of water. Calculate the concentration in terms of mass by mass percentage of the
solution. Solution
Mass of solute (salt) = 40 g
Mass of solvent (water) = 320 g
We know,
Mass of solution = Mass of solute + Mass of solvent
= 40 g + 320 g
= 360 g
$\text{mass by mass percentage}= \frac {40}{360} \times 100 = 11.1%$
Question 3.
A solution is prepared by adding 40 g of sugar in 100 g of water. Calculate the concentration in terms of mass by mass percentage of solution. Solution
Given,
mass of sugar= 40g
mass of water= 100g
To find :- concentration of sugar in water
Total mass of solution = mass of sugar + mass of water=100g +40g = 140g
percentage of concentration of sugar in solution=
$\frac {40}{140} \times 100 =28.57% $approx
Question 4.
Calculate the mass of water and mass of glucose required to make 250 g of 40% solution of glucose. Solution
We know that
Mass percent = mass of solute / mass of solution
Here mass of solution = 250g
Mass of solute = x
Mass percent = 40
Hence 40 % = x/ 250
x = 100g
Hence amount of solute needed to make 250g of 40 % solution of is 100 g
Therefore Mass of Solute = 250g - 100g =150g
Question 5.
During an experiment the students were asked to prepare a 10 % (Mass/ Mass) solution of sugar in water. Ramesh dissolved 10 g of sugar in 100 g of water while Sarika prepared it by dissolving 10 g of sugar in water to make 100 g of the solution.
(a)Are the two solutions of the same concentration?
(b)Compare the mass % of the two solutions. Solution
1. No both the solution have different concentration.
2. In case of Ramesh it is 10 gram of solute in total 110 g solution ( 10 g sugar + 100 g water)
So concentration in mass % = 10 / 110 x 100 = 9.09 %
But in case of Sarika ?it is 10 gram of solute in total 100 g solution ( 10 g sugar + 90 g water)
So concentration in mass % = 10 / 100 x 100 = 10 %
The solution prepared by Ramesh contains less amount of solute than Sarika.
Question 6.
Calculate the mass of sodium sulphate required to prepare its 20% (mass percent) solution in 100 g of water. Solution
Let mass of sodium sulphate required be x grams.
Given that the mass of water is 100 g.
20 = [x/(x + 100)] * 100
x = 25
Thus, 25g of sodium sulphate is required.
Question 7.
What volume of ethyl alcohol and water must be mixed together to prepare 250 ml of 60% by volume of alcohol in water. Solution
60% by volume of alcohol solution means, each 100 ml of solution will have 60 ml ethyl alcohol
So, 250 ml of solution will have = (60 /100) x250 = 150 ml of ethyl alcohol
Hence, In a 250 ml solution of 60% by volume of alcohol and water, alcohol should be 150 ml and water should be 100ml
Question 8.
A teacher told three students A, B and C to prepare 25% solution (mass by volume) of KOH. Student A dissolved 25 g of KOH in 100 g of water, student B dissolved 25 g of KOH in 100 mL of water and student C dissolved 25 g KOH in water and made the volume 100 mL. Which one of them has made required 25% solution? Give your answer with reason. Solution
Student C
Mass of solute = 25g
Mass of solution = 100 m
concentration % = (25/100)100
=25%
Therefore Student C has made 25% of solution(mass by volume)
Question 9.
A solution contains 50 g of sugar in 350 g of water. Calculate the concentration of solution in terms of mass by mass percent of the solution. Solution
ass of solute = 50g
mass of solvent = 350g
mass of solution = 50 + 350 = 400g
$\text {mass by mass%} = \frac {\text{mass of solute}}{\text{mass of solution}} \times 100 $
$\text{mass by mass %} = \frac {50}{400} \times 100$
= 12.5%
Question 10.
To make a saturated solution, 72 g of sodium chloride is dissolved in 200 g of water at 200C. find its concentration at the same temperature. Solution
Concentration is given by = $ \frac {\text{Mass of solute}{\text{Mass of solution}} \times 100$
mass of solute= 72g
mass of solution= 72g + 200g
$Concentration= \frac {72}{272} \times 100 = 26.47%$
5-Marks Questions
Question 1.
Write your observation when the following processes take place:
a. An aqueous solution of sugar is heated till it gets dried up.
b. A saturated solution of KCL at 60° C is allowed to cool at room temperature.
c. A mixture of iron filings and sulphur powder is heated strongly.
d. A bean of light is passed through colloidal solution.
e. Dilute HCI is added to mixture of iron filings and sulphur powder. Solution
a. When an aqueous solution of sugar is heated to dryness, the sugar will be left behind in the container after the vaporization of water.
b. we would observe crystals of potassium chloride being formed in the liquid solution
c. Iron Sulphide(FeS) will be formed
d. The light is scattered and it is called tyndall effect
e. It will separate S and Fe, to form $H_2S$ gas and iron chloride($FeCl_2$)
Question 2.
what is chromatography? How will you separate the components of black ink using chromatography? Write any two applications of chromatography. Question 3.
(a) You are given a mixture of sand, water and mustard oil. How will you separate the components of this mixture? Explain it with the help of different separation methods involved in it.
(b) Give flow diagram showing the process of obtaining gases from air. Question 4.
A.Which of the following are chemical changes and physical change?
(i) Decaying of wood
(ii) Sawing of wood
(iii) Burning of wood
(iv) Hammering of a nail into a piece of wood
B.We know that Tincture of iodine has antiseptic properties. This solution is made by dissolving
(a) iodine in alcohol
(b) iodine in vaseline
(c) iodine in $H_20$
(d) iodine in $KI$ Solution
A. Chemical change : (i) and (iii)
Physical change: (ii) and (iv)
B. (d)
Question 5.
To make a saturated solution 36 g of sodium chloride is dissolved in 100 g of water at 293 K. find its concentration at this temperature. Solution
Mass of solute (sodium chloride) =36g
Mass of solvent (water) =100g
Mass of solution = Mass of Solute + Mass of solvent
= 36g +100g = 136g
$Conc \; % = \frac {36}{136} \times 100 =26.47%$
Question 6.
Give two examples from daily life where Tyndall effect is observed. Question 7.
Identify homogeneous and heterogeneous mixtures among the following:
Air, salt solution, kerosene in water, muddy water, soil, soda water Question 8.
Show diagrammatically how water is purified in the water works system and list the processes involved.
Question 9.
(i) What is meant by crystallization? How is impure copper sulphate purified by the process?
(ii) Differentiate between simple distillation and fractional distillation. Solution
Crystallization is the process of slow precipitation of solid crystals of a substance from a concentrated homogeneous solution. It is basically a separation method in which a substance is transferred from the liquid (i.e. solution) phase to the solid state. The substance is thus obtained in pure crystalline form and has no impurity. It is used by chemists for the purification of solid substances.
Simple Distillation is the process of distillation used to seperate two substance when the boiling point difference is more than 250 C. No fractionating column is used.
fractional distillation is the process of distillation used to seperate two substance when the boiling point difference is less than 250 C.Fractionating column used to separate substance
Question 10.
(a) Compare metals and non - metals based on their physical properties. (any four points)
(b) What are metalloids? Give two examples.
(c) Identify metals from the following: Boron, sodium, mercury, carbon. Solution
a.
b. Elements which show some properties of metals and some other properties of nonmetals are called metalloids. Boron and Silicon
c. Sodium and Mercury
Question 11.
Distinguish between homogeneous and heterogeneous mixtures. Classify the following mixtures as homogeneous and heterogeneous:
(i) Tincture of iodine (ii) Smaoke
(iii) Brass(iv) Sugar solution
Crossword Puzzle
Across
1. hydrogen ______ is a color gas with a smell of rotten eggs
5. The major components in solution
6. Melting point and boiling point are _______ properties
7. Two elements are liquid at room temperature are mercury and _______ Down
2. In colliads ,The particles are called the ______ phase and the medium in which they are distributed is called the dispersion medium.
3. amount of solute present per unit volume or mass of the solution or solvent
4. denser particles are forced to the bottom and the lighter particles stay at the top when spun rapidly Solution
This Is matter around us pure extra questions with answers is prepared keeping in mind the latest syllabus of CBSE . This has been designed in a way to improve the academic performance of the students. If you find mistakes , please do provide the feedback on the mail.
