Separation Of Substances - Class 6 Chemistry - Extra Questions

Define the term handpicking.

The process used to separate slightly larger particles from a mixture by hand is called handpicking.
For example, stone pieces can be separated from wheat or rice by handpicking.


If you are given a mix of wheat, barley, and corn and asked to segregate the three then what will you do?

The mixture of wheat, barley, and corn can be separated on the basis of their identifications by picking with our hands.


What do you mean by a saturated solution?

At any particular temperature, a solution that has dissolved as much solute as it is capable of dissolving is said to be a saturated solution.


Which separation technique will you apply for the separation of wheat grains from husk?

Winnowing is a farming method developed by ancient people for separating grain from the chaff. It is also used to remove weevils or other pests from stored grain.
Wheat grains can be separated from husk by the process of winnowing.


Describe an activity to separate a mixture of sand and salt.

(i) Keep the mixture of sand and salt in a beaker and add some water to it.

(ii) Leave the beaker aside for some time the sand will settle down at the bottom.

(iii) The sand is separated by decantation or filtration.

(iv) Transfer the decanted liquid containing salt to a kettle and close its lid. Heat the kettle for some time.

(v) Salt can be separated from water by evaporation and then condensation.


How will you separate mangoes from a mixture of mangoes and apples?

Mangoes can be separated from a mixture of mangoes and apples by handpicking.
As the size of the components of the mixture is large enough, they can be easily separated by handpicking. Handpicking is a method is in which substances are separated based on their size, colour, weight and shape.


You are given a mixture of salt and sand. Can you separate them by picking?

No, we cannot separate them by picking.
A mixture of salt and sand can be separated by dissolving the mixture in water. Sand can be separated from the mixture by filtration, where sand is left on the filter paper as residue and salt solution is filtered out. Salt can be then separated from water by evaporation.


What is evaporation?

Evaporation is a process where liquid changes into a gas below the temperature at which it boils. When water gains heat energy it changes to a gas. An increase in temperature speeds up the rate of evaporation.


Name a method used to separate solid materials of different sizes.

Sieving is as a method in which two or more components are separated from a mixture on the basis of the difference in their sizes. 


Name the process used to separate heavier and lighter components of a mixture using air or wind.

Winnowing is used to separate heavier and lighter components of a mixture by wind or by blowing air. This method is commonly used by farmers to separate lighter husk particles from heavier seeds of grain. The husk particles are carried away by the wind. The seeds of grain get separated and form a heap near the platform for winnowing.


Write various methods of separation of components from their mixture.

The different methods used for separation of components from mixture are:
(i)
Handpicking
(ii)
Threshing
(iii)
Winnowing
(iv)
Sedimentation
(v)
Decantation
(vi)
Filtration
(vii)
Evaporation
(viii)
Condensation
 


Name the method used to separate the pieces of stone from grain.

Hand picking used to separate pieces of stone from grains. 
This method is used to separate those mixtures where one of the component is in small quantity and having large size such as stones in grain.


Can winnowing be used to separate components of a mixture having the same weight?

Winnowing is used to separate heavier and lighter components of a mixture. It cannot be used to separate components having same weight.


How can you separate grains from stalk?

We separate grains from stalk by threshing.


Match the column.
Separation process
The purpose for which we do the separation
What do we do with the separated components?
(1) Separate stones from rice.
(a) To separate two different but useful components.
(i) We throw away the solid component.
(2) Churning milk to obtain butter.
(b) To remove non-useful components.
(ii) We threw away the impurities.
(3) Separate tea leaves
(c) To remove impurities or harmful components.
(iii) We use both components.

The correct math is: (1)- (b) -(i), (2)-(a)-(iii), (3)-(c)-(ii)
1) Separation of stones from rice - to remove non-useful components - we throw away the solid components.
2) Churning milk to obtain butter - to separate two different but useful components- we use both the components.
3) Separate tea leaves - to remove impurities or harmful components - we throw away the impurity.


Write difference between boiling and evpaoration?

  • Evaporation is a normal process that occurs when the liquid form changes into the gaseous form whereas boiling is a process where the liquid gets heated up and vaporized due to continuous heating of the liquid.
  • Evaporation usually occurs on the surface of the liquid whereas boiling occurs throughout the liquid.
  • No bubbles are formed in the liquid during evaporation but in boiling bubbles are formed.


Describe the method of obtaining salt from seawater.

Seawater contains many salts mixed in it. One of them is common salt. When seawater is allowed to stand in shallow pits, water gets evaporated by sunlight and slowly turns into water vapor. In a few days, the water evaporates completely leaving behind the solid salts. Common salt is then obtained from this mixture of salts by further purification.


How will you separate husk or dirt particles from a given sample of pulses before cooking?

Husk or dirt particles can be separated by the winnowing method. It used to separate heavier and lighter components of a mixture by wind or by blowing air.


Write three methods of separation? 

Three different methods of separation are -
  1. Hand-picking: The method of handpicking can be used for separating slightly larger sized impurities like the pieces of dirt, stone, and husk from wheat, rice or pulses
  2. Threshing: The process that is used to separate the grain from stalks etc. is threshing. In this process, the stalks are beaten to free the grain seeds
  3. Winnowing: Winnowing is used to separate heavier and lighter components of a mixture by wind or by blowing air.


Explain the method of separation of solid-liquid mixtures.

  • When the solid particles are large such that they cannot pass through a filter paper, solid and liquid mixtures are separated by the process of filtration. 
  • Sometimes the solid particles in a liquid are very small and can pass through a filter paper. For such particles, the filtration technique cannot be used for separation. Such mixtures are separated by centrifugation. Centrifugation is the process of separation of insoluble materials from a liquid where normal filtration does not work well. The centrifugation is based on the size, shape, and density of the particles.
  • If the solid particles are heavy, they can be separated by sedimentation and decantation. If the mixture is left undisturbed for a long time, the solid particles sediment at the bottom. They can then be separated from the liquid by decantation.


What is winnowing ? Describe this method.

Winnowing is a method of separation which is used to separate heavier and lighter components of a mixture by wind or by blowing air.This method is commonly used to separate lighter husk particles from heavier seed grains The husk particles are carried away by wind and seeds get separated and form heap near the winnowing platform.


On increase of temperature, a saturated solution converts into ________ solution.

on increasing temperature, a saturated solution converts into unsaturated solution. The solubility of the solute in the solvent is directly proportional to temperature, so increasing temperature of the solution, makes a saturated solution unsaturated.




What types of material can be separated using the method of handpicking?

Components of a solid-solid mixture can be separated by handpicking.

Handpicking is used for separating slightly larger-sized impurities such as pieces of dirt, stones, husk from wheat, rice, pulses etc.

The size of particles to be separated should be large and of different colours and shape.


How will you separate husk or dirt particles from a given sample of pulses before cooking?

Husk or dirt particles can be separated by the winnowing method. In the winnowing method lighter particles are separated from heavier ones by using wind or blowing air, being lighter they will fly away from pulses.


You have prepared a saturated solution of sugar at room temperature. Is it possible to dissolve some more grams of sugar to this solution? Justify your answer.

When a solution reaches a state of saturation, no more solute can be dissolved in it. Hence in a given case, more grams of sugar cannot be dissolved into the solution at room temperature.


You have prepared a saturated solution of sugar. Is it possible to dissolve some more sugar into this solution? Justify your stand.

A saturated solution is one in which any additional solute added to the solution can no longer be dissolved. Therefore, it is not possible to dissolve some more grams of sugar for a saturated solution at the given temperature. If we increase the temperature of the solution we can dissolve more sugar.


How will you separate sugar mixed with wheat flour?

Sugar can be separated from wheat flour by sieving. Due to the difference in the size of particles, sugar will stay on a sieve and fine particles of wheat flour will pass through it.


What is sieving? Where can it be used?

Hint: The sieving method is mainly used in flour mills.

Explanation:

Sieving is a method where fine components are separated from heavy particles.

It is mainly used in flour mills to separate wheat from heavy particles like stone, husk, etc.



What is winnowing? Where is it used?

Hint: Winnowing is mainly used by farmers.

Explanation:

  • Winnowing is a method where a mixture of heavier particles and lighter particles are separated by the wind.
  • This method is used by farmers to separate the husk from heavy seeds of grain.

  • In this method, the farmer stands on the raised platform and allows the threshed food grains to fall slowly on the group the wind carries lighter particles and thereby setting out the food grains on the ground.

    Threshing, Winnowing, Hand-Picking - Class 6, Separation of Substances

 



Where is decantation used? Give two examples.

Decantation is used to separate insoluble solids or liquid from the liquid. 
(i) Rainwater is a mixture of mud and water. It is purified to some extent by decantation.
(ii) Oil and water also get separated by this method because oil floats up.


Explain the method that can be used for separating the following mixtures:
(i) Sand and husk
(ii) Wheat, sugar, and silk
(iii) Water and petrol
(iv) Rice and salt
(v) Sand and salt.

(i) Mixture of sand and husk: Sand and husk can be separated by the method of winnowing.
(ii) Mixture of wheat, sugar and silk: For separating silk from the mixture, we should follow the winnowing method because silk is lighter than the other two components and get separated. Wheat and sugar can be separated by sieving because their particles are of different sizes.
(iii) Mixture of water and petrol: Water does not dissolve in petrol. So, it can be separated by the use of separating funnel.
(iv) Mixture of rice and salt: Rice and salt can be separated by sieving.
(v) Mixture of sand and salt: Sand and salt is mixed with water, salt dissolves in water and sand can be separated by sedimentation and decantation followed by filtration. After that using evaporation, common salt is separated.


What is a saturated solution?

A solution that cannot dissolve any more of the solute at a given temperature is called a saturated solution.


Name the technique to separate the following:
(a) Cream from milk
(b) Salt from water
(c) Camphor from sand
(d) Oil from water

a)The process of centrifugation is used in dairies to separate cream from milk. Centrifugation is a method for separating the suspended particles of a substance from a liquid in which the mixture is rotated at a high speed in a centrifuge machine.

b)We can separate Salt and Water Using Distillation. We can boil or evaporate the water and the salt will be left behind as a solid. If we want to collect the water, we can use distillation. This works because salt has a much higher boiling point than water.

c)We know that camphor is a sublime substance and sand is not a sublime substance. Thus we can separate camphor from sand by heating the mixture slowly (sublimation). Vapours of camphor should be then collected and cooled down.

d)Oil being lighter forms the top layer, while water being heavier forms the bottom layer. Oil can be separated by decantation. However, a more useful method for separating oil and water is with the separating funnel.


Distinguish between evaporation and boiling.

1. Evaporation usually occurs on the surface. It may occur when the partial pressure of the vapor of a substance is less than the equilibrium vapor pressure. 
Boiling is a phase transition from the liquid phase to the gas phase that occurs at or above boiling temperature. 
2. Evaporation is a surface phenomenon.
Boiling is a bulk phenomenon.
3. Evaporation starts from the surface of the container.
Boiling starts from the bottom of the container. 


Answer in one word/ a few words.
The process by which a liquid is converted into its vapour state.

The process by which a liquid is converted into its vapour state is called vaporization.


Name the process associated with the following phenomenon :
Settling of sand when a mixture of sand and water is left undisturbed for sometime.

Settling of sand when a mixture of sand and water is left undisturbed for sometime is due to sedimentation of sand.


What is saturated solution explain with one example? 

Saturated solutions is the chemical solution containing the maximum concentration of a solute dissolved in the solvent.
$$\rightarrow$$  The additional solute will not dissolve in a saturated solution.
Ex :- Sugar solution.


A solution is said to be________if it cannot dissolved more of the substance in it.

When the solution equilibrium point is reached and no more solute will dissolve, the solution is said to be saturated. A saturated solution is a solution that contains the maximum amount of solute that is capable of being dissolved.so A solution in which no more solute can be dissolved is called a saturated solution.


Prachi 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.

Prachi makes a saturated solution of Potassium chloride in water at $$353K$$ and leaves the solution to cool at room temperature.
Observation- When a saturated solution of potassium chloride is coded at $$353K$$, the amount of potassium chloride which exceeds its solubility at lower temperature separates out as crystals.


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.

Firstly, Paheli would filter the muddy water using the muslin cloth. 
Then, she would hang the piece of alum with thread and submerge it in water and leave it untouched for some time.
She'll see that the impurities have settled down at the bottom and the water can be poured out. Now, she'll boil the poured out water using the gas stove. She can now drink the water after cooling it.


Give reasons: 
(a) Sand and saw dust cannot be separated by hand picking.
(b) Magnet is used to separate a mixture of iron and sulphur.
(c) Alum is used in purification of river water.

(a) Because in hand picking method substances should be large enough in size to be recognized and picked out by hand but sand and saw dust particles are very small in size so they can’t be picked by hand. It can be separated by filtration.
(b) Mixtures of iron and sulphur can be separated by moving a magnet over them. Iron gets attached to the magnet and hence gets separated.
(c) Water from a river, pond or lake contains very fine clay particles. To make them settle at a faster rate, a chemical substance called alum in powdered form is added to such mixtures. It dissolves in water and forms clusters with clay and dust particles making them heavier and increasing the rate of sedimentation.


Which method is mostly used for purification of solids?

Crystallization is the most commonly used method for the process of purification of solids. In this method, impure substances are dissolved in a minimum amount of water and then filtered. The filtered solution is then heated to obtain a saturated solution. It is then cooled overnight to obtain crystals of the substance.


You are provided with a mixture of petroleum and water. Can you suggest a method to separate the two?

Petroleum is lighter than water. We can separate these two by the method by the method of decantation. Light petroleum can be poured carefully as it remains at the top of the water. So, we can easily separate this by this method.


Define unsaturated solution.

Unsaturated solution: A solution that can take up (dissolve) more of the solute at a given temperature, is said to be an unsaturated solution.


State the principle involved in the separation of solid-solid mixtures. 
(a) Sieving
(b) Magnetic separation
(c) Sublimation

(a) Sieving Principle - Based on the difference in the size of the solid particles. 
Example - Mixture of rice and soil
(b) Magnetic separation Principle - One component of the mixture is a magnetic substance. 
Example - Mixture of iron and sand.
(c) Sublimation Principle - One of the components sublimes on heating.
Example - Mixture of iodine and salt, the mixture of ammonium chloride and sand.


Explain the term 'sieving'. State the structure of a sieve and explain the separation of different sized particles by sieving.

Sieving - is a method of separation, which is used for separating substances of different sizes that cannot be separated in hand picking. 
Principle - Based on the difference in size of the solid particles.
Technique of Separation - The large sized particles are separated from the small or finer particles by passing the mixture through a sieve. The sieve has a wooden frame, with a metal mesh at its base. The mixture is added from the top of the sieve, when the larger particles stay above and the finer particles collect below it on shaking the sieve. 
Examples - Separation of rice powder from soil, separation of different sized particles of diamond and of sand.


The solid particles which separate from their solution on slow evaporation are known as ____________.

The solid particles which separate from their solution on heating slowly are known as $$crystals$$.


Differentiate between the terms sedimentation and decantation with a suitable experimental technique.

Sedimentation is defined as the process of settling down of the heavier components present in a mixture. For example: When the mixture of sand in water is allowed to stand undisturbed for some time, it is observed that sand settles at the bottom.

Decantation is defined as the process of separating the liquid portion of a mixture when the heavier component settles at the bottom as sediments. In other words, it is the process of transferring a liquid from one container to another without disturbing the sediments that are present at its bottom. 
For example: When a mixture of sand and water is allowed to stand, sand settles at the bottom of a container since it is heavier. Water is present in the upper portion of the container. This can be separated from sand settled at the bottom simply by pouring in a different container without using any other separating device. This is known as decantation.


Two varieties of wheat flour can not be separated by sieving.

Wheat flour particles are the same throughout on a random observation. For sieving, you require two different particle sizes like that of coarse particles and rice, etc. So, wheat varieties can't be separated by sieving.


Draw a neat labelled diagram for separation of the following mixtures. 
(a) Coarse sand from fine sand
(b) A magnetic particle from a non-magnetic particle
(c) Naphthalene from sodium chloride
(d) Chalk and water using a filter paper
(e) Sand and water without using a filter paper
(f) Common salt from a solution of common salt and water


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Name two methods by which solid-solid mixtures can be separated.

Two methods by which solid-solid mixtures can be separated:
  1. Winnowing
  2. Hand picking


What is meant by unsaturated solution?

A solution in which more solute can be dissolved at a given temperature is called an unsaturated solution.


Explain the meaning of the term: 
Saturated Solution

A saturated solution cannot dissolve more of the solute at a given temperature. This solution contains the maximum amount of solute that can be dissolved in a solvent at a given temperature.


How are substances separated using handpicking and winnowing?

(i) Winnowing is used to separate heavier and lighter components of a mixture by wind or by blowing air. This method is commonly used by farmers to separate lighter husk particles from heavier seeds of grain.

(ii) Hand Picking is used for separating slightly larger sized impurities like pieces of dirt, stone, and husk from wheat, rice or pulses. The quantity of such impurities is usually not very large.


How can you show that your solution of copper sulphate is really saturated?

Take this saturated solution of copper sulphate some solution in a test tube and add some copper sulphate crystals. The crystals do not dissolve but settle down, which indicates that the solution is saturated.


Which method is used for purification of water by alum ?

Aluminium Sulfate, Shortly known as Alum, when added to water, reacts with the bicarbonate, alkalinities present in water, and forms a gelatinous precipitate. This floc attracts other fine particles and suspended material in raw water, and settles down at the bottom of the container.
This method is called $$\text {Sedimentation}$$


Write any two method of separation ?

1. $$\text{Filtration}$$: Filtration is a physical, biological or chemical operation that separates solid matter and fluid from a mixture with a filter medium that has a complex structure through which only the fluid can pass.

2. $$\text {Evaporation}$$: The evaporation method is used to separate a component of a mixture of dissolved solid and liquid. It is the process in which a liquid is converted to a gas by providing heat. Some liquid molecules become vapor, an equal number of liquid vapor molecules condense back into the liquid state. We can collect those vapor molecules in another chamber and condense them back to liquid. In this way, we can separate liquids from its mixture.


What is threshing ?

$$\textbf {Threshing}$$ is used for separating seeds from the harvested stalks. The method of separation is based on the fact that stalks of the crop plant and the chaff are soft materials whereas grains themselves are hard. Being soft, stalks and chaff can be broken into pieces on beating on rocks or wooden planks but grains remain unaffected. Nowadays, threshing machines are used for this purpose. Separation out of the food grains from dried plants is called threshing


What do you mean by separation ? 

$$Separation$$ is a method/ process used to separate two substances, that once formed a mixture.


Write the answer to the following question in your own words.
How are the components of mixtures separated by simple methods?

The components of mixtures are separated by simple methods like:

$$Distillation$$: Distillation and separating funnels are used in the separation of liquid mixtures. Distillation is a method that is used for separating two miscible liquids. It is based on the difference in the boiling points of two liquids. Distillation can either be simple or fractional. Simple distillation can be used for liquids which have huge difference in their boiling points whereas fractional distillation is used in case of liquids which have close boiling points. Distillation can be used in the production of gasoline, distilled water, xylene, alcohol, paraffin, kerosene apart from separating mixtures.​

$$Separating\  funnels$$: Separation using separating funnels is used in case of immiscible liquids. It is based on the difference in the density of the two liquids. It can be used in the separation of oil from water etc, two different types of immiscible oils, etc.

$$Chromatography$$: It can be used to separate the coloured components of a mixture on the basis of the difference in the speeds of the components on chromatograph paper, when dissolved in the same solvent. The adsorbent paper acts as the stationary phase; it carries the components of the mixture on the paper. The mixture acts as the mobile phase and the components get separated. The component which moves slowly (i.e., the less-soluble component) appears as a spot on the lower side of the paper. The component which moves faster (i.e., the more-soluble component) appears as a dot on the higher side of the paper.

$$Centrifugation$$: Centrifugation is the process where a mixture is separated through spinning. It is used to separate skim milk from whole milk, water from your clothes, and blood cells from the blood plasma.


Give scientific reasons.
Buttermilk is churned to get butter.

Butter milk has two components- water and fat/cream. Churning helps in the separation of these two components. The fat/cream collects on the top as a result of churning while the remaining part is left behind as liquid. 


State two ways by which a saturated solution can be changed to the unsaturated solution.

a) A saturated solution can be changed to an unsaturated solution by heating.

b) A saturated solution can be changed to an unsaturated solution by adding more solvent.


Make the mixtures and separate basic components from them.
  • Salt in water
  • Sand in water

Students make the adequate mixture and separate the components using the sedimentation and vaporization technique.
On mixing with water, sand settles down, whereas salt from solution with water. On evaporation, water vaporizes, leaving the salt behind.


Give definition of saturated solution.

A solution that contains the solute to its highest capacity at normal temperature is called a saturated solution. 
A solute when dissolved in a solvent dissolves completely. If more solute is added, it does not dissolve but remains as a substance. 


The method of separating seeds of paddy from its stalks is called ______.

The method of separating seeds of paddy from its stalks is called $$\text{threshing}.$$


What is winnowing? Where is it used? 

Winnowing is a method of separating components of a mixture. It is used to separate heavier and lighter components of a mixture by wind or by blowing air. 
This method is commonly used by farmers to separate lighter husk particles from heavier seeds of grain. 

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What do you mean by saturated solution?

At any particular temperature, a solution that has dissolved as much solute as it capable of dissolving is said to be a saturated solution.


What is sieving? Where is it used? 

Sieving is a process by which fine particles are separated from the bigger particles by using a sieve. It is used in a flour mill or at a construction site. In flour mills, impurities like husks & stones are removed from wheat, pebble, and stones are removed from sand by sieving. 


Identify the separation technique used :
(1) To separate the components of the ink.
(2) To separate cream from milk
(3) To separate alcohol from water 
(4) To separate mustard oil from water.

(1) Chromatography
(2) Centrifugation
(3) Distillation
(4) Separating funnel


Explain evaporation, condensation, and distillation.

  • The process of conversion of water into its vapour is called evaporation.
  • The process of conversion of water vapour into its liquid form is called condensation.
  • Distillation involves two processes i.e. evaporation followed by condensation. Distillation is the process of heating water to form water vapours and then cooling the hot water vapour to get water.


Is it possible to separate sugar mixed with wheat flour? If yes, how will you do it? 

Yes, sugar can be separated from wheat flour by sieving. Due to the difference in the size of particles, sugar will stay on top of a sieve and fine particles of wheat flour will pass through it. 


Explain with example: Sedimentation and Decantation.

  • Sedimentation: The process of setting down of heavier insoluble particles from mixture is called sedimentation.

  • Decantation: The process of transferring the clear and clean liquid without disturbing the sediments is called decantation.

Example: This method can be used to separate a sand and water mixture. First, the mixture is left undisturbed so that the sand can settle down. This is sedimentation. The water is then slowly removed by pouring it into another container without shaking the sediment. This is decantation.


Explain vaporisation by giving one example.


The process of conversion of liquid into vapour is called vaporisation. Salt from seawater can be separated by vaporisation. For this, seawater is collected in small areas called lagoons, water vaporises by the heat of the sun and salt remains in lagoons.

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A child took 3 glasses of equal quantity of water and put half teaspoon salt in one glass and two teaspoon salts in the other.Which is the concentrated solution? Justify your answer.

The concentrated solution is in the second glass because greater the amount of solute, more concentrated the solution will form.


Explain what are saturated and supersaturated solution?

The solution obtained by dissolving maximum amount of solute at a given temperature is known as saturated solution. A solution which contains more amount of solute than that is required to saturate it is known as supersaturated solution.


Name and explain the method of separation of husk from paddy.

Winnowing is the method that is used for the separation of husk from paddy. It is used to separate heavier and lighter components of a mixture by wind or by blowing air. The husk particles, being lighter, are carried away by the wind. The seeds of paddy get separated and form a heap near the platform for winnowing.


List down some advantages of distillation over evaporation?

Distillation is more advantageous than evaporation because
1.) Distillation is a fast process while evaporation is a slow process.
2.) The liquid lost during distillation is recovered after condensation while in evaporation it isn't recovered.
3.) Evaporation cannot be used to separate two or more miscible liquids present in a solution whereas distillation can be used for separating two or more miscible liquids.


Write the various methods of separation of components from their mixture.
a) Hand picking
b) Threshing
c) Winnowing
d) Sedimentation
e) Decantation
f) Filteration
g) Evaporation
h) Condensation 

(a) Hand-picking:- It is the process of separating solid impurities like pieces of stone, husk from rice, wheat, pulses by hand.

(b) Threshing:- It is the process of separating grains from stalks by beating the stalks to free grain seeds.

(c) Winnowing:- Winnowing is the process of separating heavier and lighter components of a mixture by wind or blowing air. Husk and grain are separated by this process.

(d) Sedimentation:- Sedimentation is the process of letting down the suspended material in liquid by gravity.

(e) Decantation:- Decantation is the process of separating solids from liquid or recovering the precipitate. This process is used for the purification of water.

(f) Filteration:- Filteration is a process of separating solids from liquids with the help of filter papers. It may be mechanical, physical, or biological.

(g) Evaporation:- It is the process of formation of vapours from the liquid. Salt is made from seawater by this process.

(h) Condensation:- Condensation is the process of forming liquid from vapours.


Explain the methods that can be used for separating the following mixtures: 
i) Sand and husk 
ii) Wheat, sugar and stalk 
iii) Water and petrol 
iv) Rice and salt 
v) Sand and salt 

i) Sand and husk can be separated by winnowing. The heavier particles of sand and lighter particles of husk can be easily separated by blowing air.

ii) For separating stalk from the mixture, we should follow the winnowing method as stalk is light and will blow away by air. Wheat and sugar can be separated by sieving because they are of different sizes. 

iii) Mixture of water and petrol (oil) can be separated using separating funnel as water does not dissolve in petrol. 

iv) Rice and salt can be separated by sieving as they are of different sizes.

v) Sand and salt can be mixed with water, as salt dissolves in water. Then sand can be separated by sedimentation and decantation followed by filtration because sand particles are heavier. After that using evaporation, common salt can be separated from the water. 


Which are the methods that can be used to separate the components of a mixture made of common salt, ammonium chloride, and sand? Write the methods in the order, in which they are applied.

Order of method is:
Sublimation→Filtration→Distillation
Sand can be separated by filtration/sedimentation. 
Ammonium chloride can be seaparated using sublimation.
And you get the sodium chloride in the end.
Sublimation→Filtration→Distillation


Find the method of separation of components in the following mixture:
(I) Tea dreg from tea.

Filtration is the method used for separating the liquid components from the solid components. Tea dregs refers to sediment at the bottom of a liquid such as tea.



Some sugar is added into a saturated solution of sugar in a beaker. What process/processes if any, do you expect to happen with the passage of time? What is this state called?

Two processes namely dissolution and precipitation will continue to take place at equal rates. It is called a state of equilibrium.


How can we separate a mixture of Salt, Rava and Mustard?

First, add water to this mixture. As we know salt dissolves in water, while Rava and Mustard seeds won't. Now this solution can be filtered, salt along with water will pass through the filter but Rava and mustard won't. Rava and mustard can be separated by handpicking as they are different in shape and size. The salt can be separated from saltwater by the method of evaporation or distillation, where water is allowed to vaporise leaving behind the salt.


Find out the relation and fill in the blank.
Separation salt from saline water:: Evaporation; Separation of components from black colored ink:: _______.

Separation salt from saline water:: Evaporation; Separation of components from black colored ink:: Chromatography.
Colored components of a mixture can be separated by a technique called chromatography. 


The technique used to separate the light particles from heavy particles using the flow of wind is called ________.

The technique used to separate the light particles from heavy particles using the flow of wind is called winnowing.
Example: Separation of lighter particles like fodder from grains, separation of husk and seeds of grain.


Class 6 Chemistry Extra Questions