Class 9 - Arihant - All in one (Science) - Is matter around us Pure?Contact Number: 9667591930 / 8527521718Class 9 - Arihant - All in one (Science) - Is matter around us Pure?Contact Number: 9667591930 / 8527521718A solution contains 50 g of common salt in 450 g of water. Calculate the concentration of the solution.
4g of a solute is dissolved in a 40 g of water to form a saturated solution at . Calculate the solubility of the solute at .
What is meant by a substance?
List the points of differences between homogenous and heterogeneous mixtures.
or
Differentiate between homogeneous and heterogeneous mixtures with examples.
To make a saturated solution, 36g of sodium chloride is dissolved in 100 g of water at 293 K. Find its concentration at this temperature.
How will you separate a mixture containing kerosene and petrol (difference in their boiling points is more than ), which are miscible with each other?
Name the technique to separate
1. butter from curd
2. salt from sea water
3. camphor from salt
What type of mixtures are seperated by the technique of crystallisation?
Classify the following as chemical or physical changes:
1. cutting of trees,
2. melting of butter in a pan,
3. rusting of almirah,
4. boiling of water to form steam,
5, passing of electric current through water and the water breaking down into hydrogen and oxygen gases,
6. dissolving common salt in water,
7. making a fruit salad with raw fruits and
8. burning of paper and wood.
Try segregating the things around you as pure substances or mixtures.
Which separation techniques will you apply for the separation of the following?
1. Sodium chloride from its solution in water.
2. Ammonium chloride from a mixture containing sodium chloride and ammonium chloride.
3. Small pieces of metal in the engine oil of a car.
4. Different pigments from an extract of flower petals.
5. Butter from curd.
6. Oil from water.
7. Tea leaves from tea
8. Iron pins from sand.
9. Fine mud particles suspended in water.
Write the steps you would use for making tea. Use the words solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.
Pragya tested the solubility of three different substances at different temperatures and collected the data as given below (results are given in the following table, as grams of substance dissolved in 100 g of water to form a saturated solution).
1. What mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in 50 g of water at 313 K?
2. Pragya makes a saturated solution of potassium chloride in water at 353 K and leaves the solution to cool at room temperature. What would she observe as the solution cools? Explain.
3. Find the solubility of each salt at 293 K. Which salt has the highest solubility at this temperature?
4. What is the effect of change of temperature on the solubility of salt?
Classify each of the following as a homogeneous mixture. Soda water, wood, air, soil, vinegar, filtered tea.
How would you confirm that a colourless liquid given to you is pure water?
Which of the following materials fall in the category of pure substance?
1. Ice
2. Milk
3. Iron
4. Hydrochloric acid
5. Calcium oxide
6. Mercury
7. Brick
8. Wood
9. Air
IDentify the solution among the following mixtures.
1. soil
2. sea water
3. air
4. coal
5. soda water
Which of the following will show tyndall effect?
1. Salt solution
2. Milk
3. Copper sulphate solution
4. Starch solution
Classify the following into elements, compounds and mixtures.
1. Sodium
2. Soil
3. Sugar solution
4. Silver
5. Calcium carbonate
6. Tin
7. Silicon
8. Coal
9. Air
10. Soap
11. Methane
12. Carbon dioxide
13. Blood
Which of the following are chemical changes?
1. Growth of a plant
2. Rusting of iron
3. Mixing of iron filings and sand
4. Cooking of food
5. Digestion of food
6. Freezing of water
7. Burning of a candle
Which of the following is a pure substance?
1. Air
2. Distilled water
3. Steel
4. Brass
Which of the following statements are true for pure substances?
(i) Pure substances contain only one kind of particles.
(ii) Pure substances may be compounds or mixtures.
(iii) Pure substances have the same composition throughout.
(iv) Pure substances can be exemplified by all elements other than nickel.
1. (i) and (ii)
2. (i) and (iii)
3. (iii) and (iv)
4. (ii) and (iii)
Which of the following property does not prove that water is a compound?
1. Water is made up of two different elements (H and O). Which chemically combined with one another in a fixed proportion.
2. Water has fixed boiling point (b.p.).
3. The constituents of water cannot be separated by simple physical methods.
4. Distilled water and tap water have same taste and constituents.
Two elements X and Y combine to give a product Z. The correct statement about Z is
1. Z has more mass than that of X
2. Z has less mass than that of X
3. Z has less mass than that of Y
4. Z show same properties as that of X and Y
Two substances, A and B were made to react to form a third substance, according to the following reaction . Which of the following statements concerning this reaction are incorrect?
(i) The product shows the properties of substance A and B.
(ii) The product will always have a fixed composition.
(iii) The product so formed cannot be classified as a compound.
(iv) The product so formed is an element.
1. (i), (ii) and (iii)
2. (ii), (iii) and (iv)
3. (i), (iii) and (iv)
4. (ii), (iii) and (iv)
Which of the following substances are homogeneous in nature?
(i) Ice
(ii) Wood
(iii) Soil
(iv) Air
1. (i) and (iii)
2. (ii) and (iv)
3. (i) and (iv)
4. (iii) and (iv)
Which of the following will not show Tyndall effect?
1. Smoke
2. Foam
3. Jelly
4. Salt solution
The method used to separate a dye from blue ink is
1. evaporation
2. sedimentation
3. crystallisation
4. filteration
The most suitable technique used to separate mixture of different gases from bulk of air can be
1. chromatography
2. sublimation
3. fractional distillation
4. centrifugation
Which of the following are chemical changes?
(i) Decaying of wood
(ii) Burning of wood
(iii) Sawing of wood
(iv) Hammering of a nail into a piece of wood
1. (i) and (ii)
2. (ii) and (iii)
3. (iii) and (iv)
4. (i) and (iv)
Assertion A solution of table salt in a glass of water is homogeneous.
Reason A solution having different composition throughout is homogeneous.
1. If both Assertion and Reason are true and reason is the correct explanation of Assertion.
2. If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
3. If assertion is true but Reason is false.
4. If assertion is false but reason is true.
Assertion A mixture of sugar and benzoic acid can be separated by shaking with ether.
Reason Sugar is insoluble in water.
1. If both Assertion and Reason are true and Reason is correct explanation of assertion.
2. If both Assertion and Reason are true but Reason is not the correct explanation of th assertion.
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
Assertion True solutions exhibins Tyndall effect.
Reason Particles are very small in size.
1. If both Assertion and Reason are true and reason is the correct explanation of Assertion.
2. If both Assertion and Reason are true but reason is not the correct explanation of Assertion.
3. If Assertion is true but Reason is false.
4. If Assertion is false but Reason is true.
Assertion Impure benzoic acid can be purified by sublimation.
Reason Benzoic acid sublimes on heating.
1. If both Assertion and Reason are true and Reason is the correct explanation of explanation.
2. If both Assertion and Reason are true but Reason is not the correct explanation of assertion.
3. If Assertion is true but Reason is false
4. If Assertion is false but Reason is true.
Assertion Chromatography can be used to separate a mixture of plant pigments.
Reason Chromatography is a process of separation of components of a mixture.
1. If both Assertion and Reason are true and Reason is the correct explanation of assertion.
2. If both Assertion and Reason are true but Reason is not the correct explanation of assertion.
3. If assertion is true but reason is false.
4. If assertion is false but reason is true.
Is ice water homogeneous or heterogeneous substance? Is it pure or impure substance?
The 'sea water' can be classified as a homogeneous as well as heterogeneous mixture. Comment.
Is fresh air free of dust particles and impurities of all other kind, a pure substance?
What is meant by concentration of a solution?
Why particles in a true solution can not be seen with naked eyes?
Do suspension show the property of Tyndall effect?
State which of the following solutions exhibit Tyndall effect?
Starch solution, sodium chloride solution, tincture of iodine, smoke.
How can you seperate particles of colloidal solution? Name the process.
How can we obtain coloured component (dye) from blue/ black ink?
List the two conditions essential for using distillation as a method for seperation of the components from a mixture.
What are the favourable qualities given to gold when it is alloyed with copper or silver for the purpose of making ornaments?
Which of the tubes in the figures (a) and (b) will be more effective as a condenser in the distillation apparatus?
Salt can be recovered from its solution by evaporation. Suggest some other technique for the same.
How will you justify that rusting of iron is chemical change?
Non-metal are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non-malleable and are coloured.
1. Name a lustrous non-metal.
2. The allotropic form of a non-metal is a good conductor of electricity. Name the allotrope.
3. Name a non-metal which is known to form the largest number of compounds.
4. Name a non-metal other than carbon which shows allotropy.
5. Name a non-metal which is required for combustion.
6. Name a non-metal that form common salt with sodium.
Classify the substances given below into elements and compounds.
Which of the following are not compounds?
1. Chlorine
2. Potassium
3. Iron
4. Iron sulphide
5. Aluminium
6. Iodine
7. Carbon
8. Carbon monoxide
9. Sulphur powder
Tell whether each of the following properties describes a homogeneous mixture, a solution, a heterogeneous mixture, a compound or an element.
1. A homogeneous liquid which leaves a solid residue on boiling.
2. A cloudy liquid which after some time appears more cloudy towards the bottom.
3. A colourless liquid which boils at a definite temperature and can be decomposed into simpler substances.
What would you observe when
1. a saturated solution of potassium chloride prepared at is allowed to cool to room temperature?
2. an aqueous sugar solution is heated to dryness?
3. A mixture of iron filings and sulphur powder is heated strongly?
Why copper sulphate solution in water does not show Tyndall effect, but mixture of water and milk shows?
Explain the term 'Centrifugation'. Give its two applications.
A mixture containing two liquids is placed in seperating funnel. Answer the following questions.
1. What type of liquids form the mixture?
2. Which of the liquid will form the lower layer?
3. What is the basis of this method?
Name the process associated with the following:
1. Dry ice is kept at room temperature and at one atmospheric pressure.
2. A drop of ink placed on the surface of water contained in a glass spreads throughout the water.
3. A potassium permanganate crystal is in a beaker and water is poured into the beaker with stirring.
4. An acetone bottle is left open and the bottle becomes empty.
5. Milk is churned to separate cream from it.
6. Settling of sand when a mixture of sand and water is left undistrubuted for some time.
7. Fine beam of light entering through a small hole in a dark room, illuminates the particles in its paths.
While diluting a solution of salt in water a student by mistake added acetone (boiling point ). What technique can be employed to get back the acetone? Justify your choice.
1. Name the separation technique you would follow to separate the following mixtures.
a. Clear water from muddy water
b. Kerosene and water
c. Iron filings and sand
2. What is the advantage of fractional distillation over simple distillation?
A colloid is a _________ mixture and its components can be separated by the technique known as________.
Ice, water and water vapour look different an display different_________ properties, but they are________the same.
A mixture of chloroform and water taken in a separating funnel is mixed and left undisturbed for some time.
The upper layer in the separating funnel will be of _________ and the lower layer will be that of_________.
A mixture of two or more miscible liquids, for which the difference in the boiling points is less than 25 K can be separated by the process called_______
When light ios passed through water containing a few drops of milk. It shows a bluish tinge. This is due to the _______ of light by milk and the phenomenon is called _______. This indicates that milk is a __________solution.
Determine whether each of the following change is physical or chemical. Give reason for your answer.
1. A balloon filled with hydrogen gas explodes upon contact with a spark.
2. Copper turns green on exposure to air and water.
3. A metal surface becomes dull because of continued abrasion.
Can physical and chemical changes occur together? Illustrate your answer.
Calculate the mass of sodium sulphate required to prepare its 20% (mass per cent) solution in 100g of water?
110 g of salt is present in 550 g of solution. Calculate the mass percentage of the solution.
1. What are elements?
2. What are the three main types of elements?
3. Write a property of each type of element.
1. Distinguish among the true solution, suspension and colloid in a tabular form under the following heads:
a. Stability
b. Filterability
c. Type of mixture
2. Give expression for the concentration of a solution. How will you prepare a 10% solution of glucose by mass in water?
Write your observations when the following processes take place:
1. An aqueous solution of sugar is heated to dryness.
2. A saturated solution of potassium chloride prepared at is allowed to cool at room temperature.
3. a mixture of iron filings and sulphur powder is heated strongly.
4. A beam of light is passed through a colloidal solution.
5. Dilute HCl is added to the mixture of iron and sulphur.
1. Pond water contains sand grains, clay particles, salt, pieces of paper and some air bubbles. Select from amongst these, an example each of a solvent, solute, colloid and suspension.
2. Give one example of each of the following:
a. A solution of gas in liquid
b. A solution of two solids
c. A solution of two gases.
You are provided with a mixture of napthalene and sodium chloride by your teacher. Suggest an activity to separate them with well-labelled diagram.
Give an example each for the mixture having following characteristics. Suggest a suitable method to separate the components of these mixtures.
1. A volatile and non-volatile components.
2. Two volatile components with appreciate difference in boiling points.
3. Two immiscible liquids.
4. One of the components changes directly from solid to gaseous state.
5. Two or more coloured constituents soluble in same solvent.
1. Write the steps involved in the process of obtaining pure copper sulphate from an impure sample.
2. Give any one application of this method.
3. Why is this technique better than simple evaporation to purify solids?
1. Draw a neat and labelled diagram of the apparatus used to separate components of blue-black ink. Name the process and state the principle involved.
2. Identify the physical and chemical changes from the following.
a. Burning of magnesium in air
b. Tarnishing of silver spoon
c. Sublimation of iodine
4. Electrolysis of water
Classify each of the following as a physical or a chemical change. Give reasons.
1. Drying of a shirt in the sun.
2. Rising of hot air over a radiator.
3. Burning of kerosene in a lantern.
4. Change in the colour of black tea on adding lemon jiuce to it.
5. Churning of milk cream to get butter.
Iron filling and sulphur were mixed together and divided into two parts, A and B. Part A was heated strongly while part B was not heated. Dilute hydrochloric acid was added to both the parts and evolution of gas was seen in both the cases. How will you identify the gases evolved?
Rama tested the solubility of four substances at different temperatures and found gram of each dissolved in 100 g of water to form a saturated solution.
1. Which solution is least soluble at 293 K?
2. Which substance shows maximum change in its solubility when the temperature is raised from 293 K to 313 K?
3. Find the ammount of ammonium chloride that will separate out when 55g of its solution at 333 K is cooled to 293 K.
4. What is the effect of temperature on the solubility of a salt?
5. What mass of sodium chloride would be needed to make a saturated solution in 10g of water at 293 K?
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.
1. Are the two solutions of the same concentration?
2. Compare the mass % of the two solutions.
1. Under which category of mixtures will you classify alloys and why?
2. Whether a solution is always liquid or not comment.
3. Can a solution be heterogeneous?
