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Separation of Substances

Description: Separation of Substances, Chemistry, Science
Number of Questions: 15
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Tags: Chemistry Science Threshing Methods of Separation Separation of Substances Saturated Solution Use of More Than one Method of Separation
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The method of separating the grain from the stalk is called ____________ .

  1. winnowing

  2. seiving

  3. ginning

  4. harvesting

  5. threshing


Correct Option: E
Explanation:

It is correct. The method of separating the grain from the stalk is called threshing. It is basically the beating of dry stalks to shake off the dried grains. It can be done by hand, by cattle or by machines. Traditionally, threshing was done by hand, but cattle help do the job quickly. Nowadays, threshing machines are also used to separate large quantities of grain quickly.

Which of the following methods is not used for separation of substances?

  1. Winnowing

  2. Transfusion

  3. Evaporation

  4. Threshing

  5. Sieving


Correct Option: B
Explanation:

 Blood transfusions are used to replace blood lost during surgery or a serious injury. It means that blood is mixed with the blood in the body. Therefore it is a method of mixing and not separating substances.

Which of the following is a method of separating solid substances?

  1. Evaporation

  2. Filtration

  3. Sieving

  4. Decantation

  5. Distillation


Correct Option: C
Explanation:

It is correct. Sieving is a method of separating substances that are of different sizes. For example, wheat flour has some fine powdered wheat as well as some bigger impurities. When it is put this through a sieve, the fine powder falls through the small holes in the sieve, while the thicker impurities remain as they are too big to pass through these holes. The solid substances are thus separated.

Which of the following combinations of separating sand, salt and water is incorrect?

  1. Separation

  2. Sedimentation

  3. Evaporation

  4. Decantation

  5. Condensation


Correct Option: A
Explanation:

It is correct. The mixture of the sand, salt and water can be separated successfully using a combination of sedimentation, decantation, evaporation and condensation. The separation of solids from gas streams is a common unit operation in production plants. This is called the separation process.

Which of the following is an example of a component separated from a mixture?

  1. Soil

  2. Seawater

  3. Paneer

  4. Soap

  5. Coking oil


Correct Option: C
Explanation:

It is correct. The method of filtration is used in the process of preparing cottage cheese (paneer) in our homes. For making paneer, a few drops of lemon juice are added to milk as it boils. This gives a mixture of particles of solid paneer and a liquid. The paneer is then separated by filtering the mixture through a fine cloth or a strainer.

Which of the following substances is insoluble in water?

  1. Salt

  2. Sugar

  3. Coffee

  4. Chalk

  5. Air


Correct Option: D
Explanation:

 Chalk is insoluble in water.

What is a saturated solution?

  1. A solution which can dissolve more of the solute at a given temperature.

  2. A solution in which more quantity of a solute cannot be mixed.

  3. A solution which is overflowing from its container.

  4. A solution in which there are no unsaturated fats.

  5. A solution in which filtration is not possible.


Correct Option: B
Explanation:

Correct. A solution is said to be saturated if it cannot dissolve more of the solute in it.

Shilpa made tea for her mother. She noticed that the water boiled and then it decreased. What happened to the water as it boiled?

  1. It evaporated

  2. It distilled

  3. It decanted

  4. It saturated

  5. It filtered


Correct Option: A
Explanation:

Yes, it is correct. The water evaporated on boiling.

Match the methods of separation in column A from the substances it can be used to separate in Column B:

 
Column A Column B
1. Sieving a. Grains from the stalk
2. Decantation b. Pebbles from sand
3. Threshing c. Oil and water
  1. 1 - a, 2 - b, 3 - c

  2. 1 - b, 2 - c, 3 - a

  3. 1 - b, 2 - a, 3 - c

  4. 1 - c, 2 - a, 3 - b

  5. 1 - a, 2 - c, 3 - b


Correct Option: B
Explanation:

It is correct. All are correctly matched. Sieving can be done to separate pebbles from sand. Decantation can be used to separate oil and water. Threshing is done to separate grains from stalk.

Which of the following statements is false?

(P) Handpicking allows the good grains to be separated from the waste and impurities. (Q) A mixture of milk and water can be separated by filtration. (R) The method of separating seeds of paddy from its stalks is called threshing. (S) More of a substance can be dissolved in a solution by heating it. (T) Sieving is a method of separating substances that are of different sizes.

  1. P

  2. Q

  3. R

  4. S

  5. T


Correct Option: B
Explanation:

Yes, it is correct. A mixture of milk and water cannot be separated by filtration.

What methods of separating will he used to separate the grain seeds from the stalk and then further separation of husk from grains, before it can used it for consumption.?

Directions: Read the given scenario carefully and answer the question that follows.                                                                                                                                                                    
Suresh is a farmer and he has just harvested the paddy crop. He wants to use the rice grains for his own consumption.

  1. Threshing ---------- Winnowing

  2. Winnowing ---------- Threshing

  3. Hand picking ---------- Winnowing

  4. Hand picking ---------- Threshing

  5. Threshing ---------- Sieving


Correct Option: A
Explanation:

Correct. The method of separating the grain from the stalk is called threshing. It is basically the beating of dry stalks to shake off the dried grains. Even though the large stalks can be separated from the grains by threshing, the grains still have dried husk and chaff, which have to be separated and thrown away before the wheat can be used. This method is called winnowing. The husk is blown away as it is much lighter than the grain. So, when the grains are gently dropped to the ground, only the wheat grains collect there, while the husk blows away.

Which of the above given statements is/are correct?

Directions: Consider the following statements and answer the question that follows:

1. Filtration can be used to separate components of a mixture of an insoluble solid and a liquid.
2. Water dissolves similar amount of soluble substances in it.
3. When the heavier component in a mixture settles after water is added to it, the process is called decantation.

  1. Only 1

  2. Only 2

  3. Only 3

  4. Both 1 and 2

  5. Both 2 and 3


Correct Option: A
Explanation:

 This statement is correct. Filtration can be used to separate components of a mixture of an insoluble solid and a liquid.

The process of separation used in this example is called ___________.

Directions: Read the given passage carefully and then complete the statement given below:

Shreya went for a picnic to the forest reserves. They ran out of water and her father collected water from a stream nearby. The water was slightly muddy and her father told her to wait before they could drink it. Soon impurities settled at the bottom when muddy water was kept still. The clear water was then poured off from the top.

  1. distillation

  2. decantation

  3. winnowing

  4. filteration

  5. evporation


Correct Option: B
Explanation:

It is correct. Grains can be separated from dirt by sedimentation and decantation. When water is added to the grains, the dust and dirt dissolve in the water, making it muddy. Thus, the dirt and grains are separated. The grains settle at the bottom because they are heavier. This process of the settling of the heavier substance is called sedimentation. Now, the grains can be separated by simply pouring out the water. This process is called decantation.

There are three examples of separation of substances given above. Which of these three illustrations have followed the method of sedimentation to finally separate the substances?

Directions: Read the given statements carefully and answer the question that follows.

A. The steam that forms on boiling water turns back into water when it comes in contact with a cold metal lid.
B. The grains with dried husk and chaff, are separated and thrown away before the wheat can be used.
C. After a mixture of oil and water is separated, the water left behind can be further cleaned. After this it is further separated, and hence dirt will sift out, leaving the water clean.

  1. A

  2. B

  3. C

  4. All of them

  5. None of them


Correct Option: E
Explanation:

Correct. Example A is condensation. Example B is winnowing. Example C is filtration. Thus neither of the examples have used the method of sedimentation. So, none of them is the correct answer.

What method will her mother have to use to separate the flour and the pulses?

Directions: Read the scenario given below carefully and answer the question that follows.

Trisha was running in the kitchen when she suddenly knocked into her mother and upset the dishes she was working with. The flour her mother had taken out to make chappatis and the pulses she was going to wash for dinner had gotten mixed up.

  1. Filtration

  2. Evaporation

  3. Winnowing

  4. Sedimentation

  5. Sieving


Correct Option: E
Explanation:

Correct. Sieving is used when components of a mixture have different sizes. In this case the flour is fine and the pulses are bigger. So, by sieving the flour can be separated from the pulses.

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