SCIENCE CHAP 5 SEPERATION OF SUBSTANCE WORKBOOK

 5. Separation of substances WORKBOOK ANSWER

1. Choose the correct option. 

a) Which of the following is an example of a gas-liquid mixture? 

i) Sugar syrup ii) Lime water 

iii) Soda water iv) Sea water 

ans: Soda water 

b) ____________ method cannot be used to separate solid-solid mixtures. (a) Handpicking (b) Sieving 

(c) Winnowing (d) Evaporation 

ans: Evaporation 

c) Fine particles of sand in river water are removed by the process of ____________. (a) decantation (b) filtration 

(c) evaporation (d) sedimentation 

ans: filtration 

2. Name the following:  

a) The process of settling down of heavier insoluble particles at the bottom of a  liquid. 

ans: Sedimentation 

b) The process of conversion of water vapour into its liquid form, on cooling. ans: Condensation 

c) The method used to separate grains from their stalks. 

ans: Threshing 

d) A clear liquid obtained by the process of filtration.

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ans: Filtrate  

3. State whether the following statements are true or false. Correct the false  statements. 

a) Cobalt and nickel are magnetic materials. 

ans: True 

b) Solubility of a solute decreases with increase in temperature. 

ans: False 

Solubility of a solute increases with increase in temperature. 

c) A substance in which solute dissolves is known as a solvent. 

ans: True 

d) The constituents of all mixtures can be seen separately. 

ans: False 

The constituents of heterogeneous mixtures can be seen separately.  

4. Assertion-reasoning type questions 

In the following questions, two statements are given- one labelled Assertion (A)  and the other labelled Reason (R). Read the statements carefully and choose the  correct alternative (A), (B), (C) and (D) as given below.  

(A) Both A and R are true and R is correct explanation of the assertion. (B) Both A and R are true but R is not the correct explanation of the assertion. (C) A is true but R is false. 

(D) A is false but R is true. 

a) Assertion: Water is a universal solvent. 

Reason: Water dissolves the nutrients in soil and carries it to all parts of the  plants. 

ans: (B) Both A and R are true but R is not the correct explanation of the  assertion.

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b) Assertion: A magnet is used to separate a mixture of iron fillings from sand. Reason: Iron is a magnetic material and sand is a non-magnetic material. ans: (A)Both A and R are true and R is correct explanation of the assertion. 

5. Define the following: 

a) Decantation  

ans: The process of pouring out a clear liquid from a vessel (after  sedimentation) without disturbing the sediment is called decantation. 

b) Winnowing 

ans: The method of separating heavier and lighter components of a mixture  by wind or blowing air is called winnowing. 

6. Answer the following in brief.  

a) What are immiscible liquids? Give an example of immiscible liquids. ans: Liquids that do not mix with each other are called immiscible liquids.  Mixture of oil and water are examples of immiscible liquids.  

(examples may vary accept all correct responses) 

b) How is a homogeneous mixture different from a heterogeneous mixture? ans: A homogeneous mixture has a uniform composition and its components  cannot be seen separately whereas; a heterogeneous mixture does not  have a uniform composition and its components can be seen separately. 

c) What is solubility? List the factors affecting the solubility of a substance. ans: The amount of solute that can be dissolved in a solvent is known as the  solubility of that solvent.  

Factors affecting solubility:  

∙ Heating  

∙ Stirring  

∙ Size of solute particles

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7. Give reasons for the following statements. 

a) Water droplets are seen on the outer surface of a glass filled with ice cold  water. 

ans: This is because of the condensation of water vapours present in the  atmosphere. 

b) Powdered sugar dissolves faster in water than table sugar. 

ans: This is because solubility increases on using powdered solute. 

8. 

a) Identify and explain the process shown in the diagram. 

ans: Evaporation 

The conversion of a liquid into its gaseous state is known as evaporation. 

b) Give an example of a mixture that can be separated by this method. ans: Salt and water/ sugar and water 

9. Observe your daily life and list activities that involve the processes of  evaporation and condensation. (list at least two activities for each process) 

Evaporation	Condensation
Wet clothes dry in sunlight due to  evaporation.	Formation of dew on grass on a cold  wintery day.

ans:

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Evaporation of nail paint remover.	Formation of cloud by condensation.
After a shower, water evaporates from our body.	Formation of a fog on a window early in the morning.
Evaporation of water from earth  surface.

(answers may vary accept all relevant examples) 

10. Identify the word from the given clues: 

a) A shallow vessel with small holes at the bottom used to separate wheat bran from  flour. 

ans: Sieve 

b) A special type of paper with small pores that is used to separate sand from water. ans: Filter paper 

HOTS

11. Why do we feel cool on sweating on a hot summer day? 

ans: We feel cool on sweating on a hot summer day because sweat absorbs extra  heat from our body and gets evaporated. 

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SCIENCE CHAP-5 SEPERATION OF MATERIAL

 ANS TO TEXTBOOK QUESTION

Check your progress on page 45

Homogenous - Fog, Idli batter

Heterogeneous - Vegetable poha, Oil and water,  Salad

Check your progress page 48

1. Handpicking

2. Threshing

3. Handpicking

4. Winnowing

Check your progress page 52

1. False

2. True

3. False 

4. False

Check your progress page 56

1. Magnet

2. The Mixture of a solute and solvent is a solution.

3. Saturated solution

Answers to Let’s Exercise questions

Chose the correct option Threshing Evaporation Freezing the solution Smoke  Filtration

Fill in the blanks with the given words in the brackets Visible Blowing air Husk, grains Solute gas

State whether the following statements are true or false True False False False False

Answer the following questions in short Smoke, storms A magnet can attract magnetic materials. The materials which are not attracted by a magnet are known as non-magnetic materials. When we come across a mixture of magnetic and non-magnetic materials, we can use a magnet for separating the mixture.  Separation of mixtures into their constituents is often necessary for removal of undesirable substance and separation of useful components. A pure substance is a homogeneous material with a definite, fixed chemical composition. While impure substances are mixtures of two or more elements or compounds or both. Components of a pure substance cannot be separated by physical methods of separation while components of a impure substance can be separated by physical methods of separations such as - magnetic separation, evaporation, etc.

Define the following A saturated solution is a chemical solution containing the maximum concentration of a solute dissolved in the solvent. When a liquid changes to gas, the process is called as evaporation. When a gas changes into liquid, the process is called as condensation. Decantation is a process in which the clear liquid is transferred to another container without disturbing the sediments. A mixture is a substance made by combining two or more pure substances in such a way that no chemical reaction occurs.

Answer the following questions in detail The different methods used  to separating solid-solid mixtures are –  Handpicking – it involves simply picking out substances by hand and separating them from others. Handpicking is not preferred if the quantity of the mixture to be separated is too large. Handpicking can only be used if the impurities are visible and large enough to be picked out.  Threshing – is used to separate the seeds or grains from the stalks of the plants.  Winnowing -The method of separating heavier and lighter components of a mixture by wind or blowing air is called winnowing. Chaff from the grains is separated by blowing air. Sieving- when the components of a mixture are of different sizes, a sieve can be used to separate them. A sieve is a shallow vessel that has small holes at its bottom. The size of the holes in the sieve depends on the size of the components to be separated. The method of separating the components of a mixture that are of different sizes by using a sieve is called sieving. Evaporation is used for separating a mixture of a soluble solid and a solvent. The process involves heating the solution until the solvent evaporates leaving behind the solid residue. The water vapor can be condensed to collect the water. Mixture is a combination of two or more substances to make either a compound or a solution. It has two major types: A homogeneous mixture is a mixture where the components that make up the mixture are uniformly distributed throughout the mixture.  A heterogeneous mixture is a mixture where the components of the mixture are not uniform.

Diagram based question A- oil B- water

HOTS We see water droplets outside of a cold glass or bottle because of condensation of water vapours. River water is constantly being restocked by fresh water from rain and springs, thus they do not taste salty. But the sea collects all of the river water salt and minerals from all of the rivers that flow into it and becomes saltier. Hence, River water is sweet while sea water is salty.

 संस्कृत (पाठ 5 ) - मध्यम: पुरुष:

https://drive.google.com/file/d/1oH4ASIHFTY0TBh0M-_hdJRy0B2jSthp0/view?usp=sharing

STD: 6 SUB : GUJARATI [ CH: 8]

                   poem video :  https://www.youtube.com/watch?v=U3c8sFDtWK8 

STD: 6 SUB: GUJARATI [CH: 2 ]

 

 संस्कृत  पाठ ४- प्रथम: पुरुष:

https://drive.google.com/file/d/1IJjbPGYRapZ1udwcx1bOVuBhA8XOUvF_/view?usp=sharing

Ch 2 - Introduction to OpenOffice Calc

1. Shortcut Keys File

2. Textbook Exercise Answer sheet

3. Workbook Answer Sheet 

SCIENCE GROUPING MATERIALS WORKBOOK Q -ANS

 4. Grouping materials WORKBOOK Q-ANS

1 Choose the correct option. 

1. Identify the gas that does not dissolve in water. 

(a) oxygen (b) methane 

(c) carbon dioxide (d) both (b) and (c) 

ans: methane 

2. Which of the following substances is lustrous? 

(a) sand (b) plastic 

(c) brass (d) wood 

ans: brass 

3. Identify the correct statement. 

(i) Solids have definite shape but do not have definite volume. (ii) Gases have definite volume but do not have definite shape. (iii) Liquids have definite volume but do not have definite shape. (a) only (i) (b) only (ii) 

(c) only (iii) (d) both (i) and (ii) 

ans: only (iii) 

2 In the following questions, two statements are given- one labelled  Assertion (A) and the other labelled Reason (R). Read the statements  carefully and choose the correct alternative (A), (B), (C) and (D) as  given below.  

(A) Both A and R are true and R is the correct explanation of the  assertion. 

(B) Both A and R are true but R is not the correct explanation of the  assertion. 

(C) A is true but R is false. 

(D) A is false but R is true.

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1. Assertion: A substance exists in solid state. 

Reason: The molecules of solids can move throughout the volume  occupied by the substance. 

ans: (C) A is true but R is false. 

2. Assertion: An iron nail sinks in water. 

Reason: The density of the iron nail is more than water. 

ans: (A) Both A and R are true and R is the correct explanation of the  assertion. 

3 State whether true or false. Correct the false statements. 

1. Chalk is soluble in water. 

ans: False 

Chalk is insoluble in water. 

2. Stones and metal keys float on water. 

ans: False 

Stones and metal keys sink in water. 

3. Cotton is soft and iron is hard. 

ans: True 

4 Classify the following things as transparent, translucent and opaque . (marble, water, frosted glass, glass door, brick, butter paper)

Transparent

Translucent

Opaque

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glass door  water

frosted glass  butter paper

marble  brick

5 Answer in one sentence. 

1. Name five objects that can be made from wood? 

ans: Table, chair, door, boat, bed 

(answer may vary, accept all correct answers) 

2. What are immiscible liquids? 

ans: The liquids which do not dissolve in water are called immiscible  liquids.  

3. How are rough materials different from smooth materials? 

ans: Rough materials have irregular surfaces with bumps or ridges whereas  smooth materials have plain and even surfaces. 

6 Give reasons for the following statements. 

1. Sweets are kept in transparent glass containers in sweet shops. 

ans: Glass is transparent and can make light pass through it. When sweets  are kept in glass containers, it is easy for the customer to select their  choice of sweet without touching it. 

2. Metals are lustrous, but the iron used in window grills does not shine. ans: The iron used in window grills does not shine because it reacts with  air and moisture. This results in rough appearance and reddish brown  colour. 

7. The arrangement of molecules in three different substances is shown below. Observe 

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the figure and identify whether the substances are solids, liquids or gases. Justify your  answer. 

________________________ _________________________ _________________________ ________________________ _________________________ _________________________ ________________________ _________________________ _________________________ ________________________ _________________________ _________________________ 

Gaseous substance  because the particles are  

very far from each other. 

Liquid substance  because the particles  are close but not as  close as in solids. 

Solid substance  

because the particles  are very close to each  other.

8. Zain, Mira, Tim and Ella were given red chilli powder, butter, kerosene and honey respectively, and were asked to check the solubility of each in water. Design an experiment that they can conduct to identify the soluble substances. ans: 

Take four test tubes. Fill 1/3 rd of the test-tubes with water. Add red chilli  powder, butter, kerosene and honey respectively in each test tube using a  spatula. Shake the test tubes and allow the test tubes to stand for fifteen  minutes. Record the results in the following table: 

Test Observation Inference 

1. red chilli powder + Red chilli powder is  seen at the bottom of  

Red chilli powder is  

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water the test tube. insoluble in water. 

2. butter+ water Butter is seen floating  on water. 

3. kerosene+ water Kerosene forms a  separate layer on water. 

Butter is insoluble in  water. 

Kerosene is insoluble in  water. 

4. honey + water Clear water is seen. Honey is miscible in  water. 

HOTS

Take a small cotton ball and place it in a tumbler/ bowl filled with water. Observe it for at  least 10 minutes. Will it float or sink in water? Why? 

ans: The cotton ball will absorb water and sink to the bottom. This is due to  increase in the density of the cotton ball after absorbing water.