Separation of Substances: Class 6 Science Q&A
37 free answers on Separation of Substances (Science) for Class 6 students, across CBSE, ICSE and State boards. Includes questions such as “Common salt is obtained from seawater through the process of evaporation.”, “Why is an impure substance considered to be a mixture?”, “Name any two methods used to separate:”.
Question & Answer
Questions
- ScienceClass 6CBSE
Common salt is obtained from seawater through the process of evaporation.
Seawater is collected in shallow pits or large tanks called salt pans. These pans are exposed to sunlight. Due to the heat of the sun, the water slowly evaporates and turns into water vapor. As the water evaporates, the dissolved salts remain behind in solid form. After complete evaporation, the salt crystals are collected from the pans. However, this salt may still contain impurities. Therefore, it is further cleaned and purified to obtain pure common salt su
- ScienceClass 6CBSE
Why is an impure substance considered to be a mixture?
An impure substance contains unwanted materials or impurities along with the main substance. These impurities may be present in small amounts but can still affect the properties of the substance. Since it contains more than one type of particle, it is considered a mixture. The components of an impure substance can often be separated by physical methods, which is another characteristic of mixtures.
- ScienceClass 6CBSE
Name any two methods used to separate:
Solid-solid mixtures: Two methods used for separating solid-solid mixtures are: Hand picking – Used when one component is present in small quantity and can be easily picked out by hand (e.g., removing stones from rice). Winnowing – Used to separate lighter particles from heavier ones using wind (e.g., separating husk from grains). (b) Liquid-solid mixtures: Two m
- ScienceClass 6CBSE
What are heterogeneous mixtures?
Heterogeneous mixtures are those mixtures in which the different components are not uniformly mixed and can be seen separately with the naked eye. The composition is not the same throughout the mixture. Examples include dust in air, muddy water, and a mixture of sand and salt. In such mixtures, the particles are unevenly distributed.
- ScienceClass 6CBSE
Write any two properties of a mixture.
. Mixtures have several important properties. Two of them are: The components of a mixture can be present in any proportion or ratio. There is no fixed composition. The components of a mixture can be separated by physical methods such as filtration, evaporation, or hand picking. No chemical reaction is needed for separation.
- ScienceClass 6CBSE
Name the process which is used to separate grains from stalks.
The process used to separate grains from stalks is called threshing. In this process, harvested crops are beaten or crushed so that the grains get separated from the stalks. This can be done manually or with the help of machines.
- ScienceClass 6CBSE
Which non-useful substance is left after the preparation of tea?
After preparing tea, the non-useful substance left behind is tea leaves or tea granules. These are separated from the liquid tea using a strainer before drinking.
- ScienceClass 6CBSE
Name the two types of mixtures.
Mixtures are classified into two main types: Homogeneous mixtures – These mixtures have a uniform composition throughout. The different components cannot be distinguished easily. For example, salt dissolved in water. Heterogeneous mixtures – These mixtures do not have a uniform composition, and their components can be seen separately. For example, sand in water or oil in water.
- ScienceClass 6CBSE
What is a pure substance?
A pure substance is a material that is made up of only one type of particles and has a fixed composition throughout. This means that its properties remain the same in every sample. Pure substances cannot be separated into simpler substances by physical methods. Examples of pure substances include pure copper, pure gold, and pure water. These substances have uniform characteristics and are not mixed with any other material.
- ScienceClass 6CBSE
A mixture of iron nails, salt, oil and water is provided to you. Give stepwise methods to separate each component from this mixture.
A mixture of iron nails, salt, oil and water can be separated by the following steps: Iron nails can be handpicked or remove by magnet by attracting Oil can be removed by decantation method or separating By evaporation method, evaporate the salt and water Hence water can be condensed back leaving behind the salt at the bottom.
- ScienceClass 6CBSE
Read the story titled “WISE FARMER” and tick the correct option to complete the story. A farmer was sad/happy to see his healthy wheat crop ready for harvest. He harvested the crops and left it under the sun/rain to dry the stalks. To separate the seeds from the bundles of the stalk he handpicked/threshed them. After gathering the seed grains he wanted to separate the stones and husk from it. His wife winnowed/threshed them to separate the husk and later sieved/handpicked to remove stones from it. She ground the wheat grains and sieved/filtered the flour. The wise farmer and his wife got a good price for the flour. Can you tell why?
Solution: Happy Sun Threshed Winnowed Handpicked Sieved The wise farmer and his wife got a good price for the flour because they used correct methods to get good quality of flour.
- ScienceClass 6CBSE
Paheli was feeling thirsty but there was only a pot of water at home which was muddy and unfit for drinking. How do you think Paheli would have made this water fit for drinking if the following materials were available to her. [Alum, tub, muslin cloth, gas stove, thread, pan and lid.]
Solution: With the following materials available: alum, tub, muslin cloth, gas stove, thread, pan and lid Paheli could undertake the following steps to purify water. Firstly, filter the muddy water with the help of muslin Now, tie the piece of alum with thread and submerge it in water for some time and then leave water undisturbed. After some time, the impurities will settle down at the bottom and the water from the top can be decanted.
- ScienceClass 6CBSE
Both Sarika and Mohan were asked to make salt solution. Sarika was given a teaspoonful of salt and half a glass of water, whereas Mohan was given twenty teaspoons full of salt and half a glass of water. 1. How would they make salt solutions? Who would be able to prepare saturated solution?
Solution: To make a salt solution, mix the salt in water and by continuous stirring results in salt solution. Mohan will be able to prepare saturated solution when some salt will be left undissolved even after mixing the maximum salt in water.
- ScienceClass 6CBSE
Match the mixtures in column I with their method of separation in column II. Column I Column II (a) Oil mixed in water (i) Sieving (b) Iron powder mixed with four (ii) Hand picking (c) Salt mixed with water (iii) Decantation (d) Lady’s figure mixed with French beans (iv) Magnet (e) Rice flour mixed with kidney beans (v) Evaporation
Solution: The correct match is: Column I Column II (a) Oil mixed in water (iii) Decantation (b) Iron powder mixed with four (iv) Magnet (c) Salt mixed with water <td width="336
- ScienceClass 6CBSE
1. Name and describe briefly a method which can be helpful in separating a mixture of husk from grains. What is the principle of this method?
By using the process of winnowing, husk can be separated from grains. When the mixture is allowed to fall down from a height, the lighter husk is carried away by air and reaming falls on the ground. This method is based on the principle that a mixture with components of different weights, the lighter particles are blown away by wind.
- ScienceClass 6CBSE
State whether the following statements are true or false. (a) A mixture of oil and water can be separated by filtration. (b) Water can be separated from salt by evaporation. (c) A mixture of wheat grains and wheat flour can be separated by sieving. (d) A mixture of iron filings and rice flour can be separated by magnet. (e) A mixture of wheat grains and rice flakes can be separated by winnowing. A mixture of tea leaves and milk can be separated by decantation.
The statements are: False – Since, a mixture of oil and water can be separated by separating True True True True True
- ScienceClass 6CBSE
Fill in the blanks with appropriate words. (i) Small pieces of stone can be removed from rice by . (ii) are obtained from stalks by threshing. (iii) Husk from wheat flour is generally removed by . (iv) The process of settling of heavier particles is called . (v) Filtration is helpful in separating an insoluble from a .
hand picking grains sieving sedimentation solid, liquid
- ScienceClass 6CBSE
Sheela, Saima and Ravi have to dissolve maximum amount of sugar in the same amount of milk so as to win in a game. Ravi took hot boiling milk while Saima took ice cold milk. Sheela managed to get milk at room temperature. Whom do you think would win the game and why?
The solubility of solids in liquids increases with temperature. Ravi would win the game because he will be able to dissolve maximum amount of sugar in hot boiling milk. Saima will be able to dissolve minimum amount of sugar in ice cold milk. Sheela will be able to dissolve more sugar than Saima since the milk is at room temperature.
- ScienceClass 6CBSE
Paheli asked for a glass of water from Boojho. He gave her a glass of ice cold water. Paheli observed some water droplets on the outer surface of the glass and asked Boojho how these droplets of water were formed. Which of the following should be Boojho’s answer? (a) Evaporation of water from the glass. (b) Water that seeped out from the glass. (c) Evaporation of atmospheric water vapour. Condensation of atmospheric water vapour.
: Condensation of atmospheric water The droplets of water were formed when the air reaches the surface of ice cold glass, the water vapour of the atmosphere are condensed to form water droplets on the outer surface of glass.
- ScienceClass 6CBSE
During summer, Boojho carries water in a transparent plastic bottle to his school. One day he left his bottle in the school. The bottle still had some water left in it. The following day, he observed some water droplets on the inner surface of the empty portion of the bottle. These droplets of water were formed due to (a) boiling and condensation (b) evaporation and saturation (c) evaporation and condensation condensation and saturation.
Solution: : evaporation and condensation The water droplets were formed due to high temperature in summers; the water gets heated in plastic bottle and evaporates. This happens because the vapours reaches the lid of the bottle and condense to form water droplets which gets collected on the empty portion of the bottle.