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1. Gold and Silvr are used in the preparation of ornaments.

2. Copper and Aluminum are used in the preparation of utensils and in electric cables.

1. There are about 90 natural elements.

2. Plutonium is an artificial element.

Ammonia of the gas is highly soluble in water.

Solution and Suspension

Solution

1. It is an example of the homogeneous mixture.

2. It is formed when a solid dissolves in liquid.

3. For example – sugar dissolved in water.

Suspension

1. It is an example of the heterogeneous mixture.

2. It is formed when an insoluble solid is added to the solvent.

3. For example-chalk dissolved in water.

The smallest particle of a compound is called molecule.

Yes, food that we eat is a mixture of carbohydrates, proteins, fats, minerals, and vitamins.

Correct answer is a. Elements

Compounds are those substances which can be decomposed into constituent elements or can be synthesized out of constituent elements.

A solvent of Iodine is Alcohol

1. Winnowing 

2. Filteration 

3. Hand picking 

4. Churning 

5. Sieving

False. 

Handpicking can be used as a separation technique if the particle size of the constituents of the mixture is the not the same.

1. Winnowing

2. Hand Picking

The technique that you use if only the solid component of a solution is required Evaporation.

Carbon dioxide, air, water, milk, common, salt, blood, fruit juice, iron sulphide.

Carbon dioxide — (Compound)

air — (Mixture)

water — (Compound)

milk — (Mixture)

common salt — (Compound)

blood — (Mixture)

fruit juice — (Mixture)

iron sulphide — (Compound)

Mixtures are impure substances made up of two or more substances. Mixtures may be solids, liquids or gases.

They are heterogeneous.

(a) “Mixtures can be defined as. a kind of matter which is formed by mixing two or more pure substances (elements and compounds) in any proportion, such that they do not undergo any chemical change and retain their individual properties. Therefore they are impure substances. 

(b) Because: The mixtures contain unwanted substances which may be harmful and may degrade the properties of mixtures. So we, need to separated them and extract useful substances. 

This is necessary because 

(i) It removes unwanted and harmful substances 

(ii) to obtain pure and useful substances for them. 

Example: Seawater is rich in common salt which is an important ingredient of our food to add taste and nutrients. But sea water, cannot be directly used to get the salt. Hence, it is necessary to separate both. 

(c) Compound 

1. A compound is formed from its constituent elements as a result of chemical reaction. 

2. A compound is always homogeneous in nature. 

3. In a compound the elements are present in a fixed ratio by weight. 

4. The components of a compound can’t be separated by physical methods but can be separated by chemical methods only. 

5. The properties of a compound are different from those of its elements. 

6. The formation of a compound from its elements is accompanied by energy changes. 

Mixture 

1. A mixture is obtained from its (elements, compounds) components as a result of the physical change. 

2. The mixtures can be homogeneous or heterogeneous. 

3. In a mixture the components can be present in any ratio. 

4. The components of a mixture can be separated by physical methods only. 

5. The properties of a mixture lie between those of its components. 

6. The formation of a mixture from its constituents is not accompanied by energy changes.

Filter Paper and Alum

Filter Paper

1. It is a special paper fitted in funnel during filtration.

2. It does not dissolve in water.

3. It does not speed up-loading.

Alum

1. It is a solid which is used to load suspended mud particles in water.

2. It dissolves easily in water.

3. It speeds uploading

In using distillation:

1. Allow sufficient space to work in, working area should be well lit and well ventilated to prevent the accumulation of alcoholic vapours.

2. Keep a fire extinguisher handy.

3. There should be no obstruction in the piping that could cause pressure build-up in the stills and cause it to burst.

In using separating funnel:

1. Stopper should be tightly fitted so that the solution does not leak out when the separating funnel is inverted. 

2. Never throw any layer away until you are absolutely sure that you isolated the final product.

We can separate iron metal from non-magnetic impurities by the method of magnetic separation.

homogeneous mixtures

False. 

A heterogeneous mixture has a non-uniform composition throughout the mixture.

Bromine, Soil, Water, Iron, Air, Helium, Sugar, Lime Juice, Methane, Carbon.

During filtration, the substance left behind on the filter paper is called residue.

1. Elements are made up of same kind of atoms.

2. Elements and compounds are pure substances.

3. In a mixture, the substances are not combined chemically.

4. Clay is separated from water by the method called loading and decantation.

5. Crystallisation is a process to obtain a very pure form of a solid dissolved in a liquid.

6. Camphor and ammonium chloride can sublimate

Centrifugation: It is a process which involves application of centrifugal force.

1. It is used in industrial and laboratory settings. It is used for separation of fluids, gas or liquid based on density. In centrifugation mixture is separated through spinning and the solid settles to the bottom and the solution is clear.

2. Best example of centrifugal force is working of washing machine when it dries the clothes. The wet clothes are moving in circular path and a force acts on water particles in clothes and this force pulls water all outer side. Force involved is centrifugal force which removes the water from the clothes and clothes are dried in this way.

3. Cream separation: When the machine moves, the rod set inside milk moves and milk is pressurised and solid part from this milk goes outside due to centrifugal force and this solid part is cream. In this way the cream is separated from the milk.

During centrifugation, solid particles of the mixture move towards the bottom. True

In Chromatography two properties of substances are used,

(a) They are the stability of the substances in the solvent that moves up. The ability of the substance to stick to the stationary filter paper,

(b) So all the components of the mixture do not rise all the way to the upper end of the filter paper but remain behind at limited heights.

• Paper Chromatography
• Column Chromatography
• Thin Layer Chromatography
• Gas Chromatography.

1. Sublimation: Change of solid into vapors directly on heating and change of vapors into solid again on 

Example: Salt from ammonium chloride. 

2. Filtration: The process of separating insoluble solid particles from a liquid by allowing it to pass through a filter is called Alteration. These filters allow liquids to pass through them but not solids. The insoluble solid left on the filter is called the residue, while the liquid which passes through the filter is called the filtrate. Mixtures like chalk and water, clay and water, tea and tea leaves, sawdust and water, etc., are separated by this method. 

3. Sedimentation and decantation: The settling down of suspended, insoluble, heavy, solid particles in a solid-liquid mixture when left undisturbed is called sedimentation. The solid which settles at the bottom is called sediment while the clear liquid above it is called supernatant liquid. The process of pouring out the clear liquid, without disturbing the sediment, is called decantation. 

Example: A mixture of sand and water. 

4. Solvent extraction method: This method is used when one of the solid components is soluble in a liquid. 

Example: A mixture of sand and salt can be separated by this method. Salt gets dissolved in water while sand settles down in the container. The salt solution is then decanted. Salt is separated from the solution by evaporation. In this way, they can be separated. 

5. Magnetic separation: This method is used when one of the components of the mixture is iron. Iron gets attracted towards a magnet and hence can be separated. Mixtures of iron and sulphur, iron and sand, etc., can be separated by moving a magnet over them. Iron gets attached to the magnet and is separated. 

6. By using a separating funnel: It is a simple device used to separate the components of a liquid-liquid heterogeneous mixture. 

Example: Kerosene oil and water. The mixture is placed in a separating funnel and allowed to stand for some time. The components form two clear layers. Water being heavier forms the lower layer and oil being lighter forms the upper layer. When the stopper of the funnel is opened, the heavier liquid trickles out slowly and is collected in a vessel. The stopper is closed when the bottom layer has entirely removed from the funnel. In this way, the two liquids are separated. 

7. Fractional distillation: The process of distillation is used for separating the components of a homogeneous liquid-liquid mixture, like water and alcohol. This is based on the fact that alcohol boils at a lower temperature than water. The vapor of alcohol is collected and cooled while water is left behind in the original vessel. Thus, two liquids having different boiling points can be separated by distillation provided that difference in their boiling points must be 25 °C or more.

During filtration, the substance left behind on the filter paper is called residue.

1. The salt and water are mixed to give saltwater and can both be separated.

2. It can be separated by boiling saltwater. 

3. Water can be obtained by condensation whereas the salt will be leftover. 

4. As the salt and water do not react chemically and they are separated by simple processes therefore saltwater is called a mixture.

1. residue.

2. distillate.

3.decantation

4. fractional distillation.

Solutions are homogeneous mixtures.

1. If a magnet is moved through this mixture all iron filings will stick to the magnet, remove them. 

2. Add water to the remaining mixture, all salt will dissolve and then filter through filter paper. 

3. Samolina will settle in filter paper. 

4. The filtrate will be saltwater and salt can be separated by evaporation or distillation.

Liquid when boiled turns into gaseous state (e.g. water vapours) and on cooling it condenses to liquid.

stationary phase

Centrifugation: It is a technique used to speed up sedimentation of fine particles suspended in a solid-liquid mixture.

Principle: The principle of centrifugation is that an object, when spun at high speed, experiences an outward force away from the center of rotation.

1. Evaporation: Is the process of converting a liquid into its vapors state either by exposing it to air or by heating.

2. Filtration: The process of separating solid particles from the liquid by allowing it to pass through a filter paper is called filtration.

3. Sublimation: The process in which a solid changes directly into its vapors on heating is called sublimation.

4. Distillation: Distillation is the method of getting a pure liquid from a solution by evaporating and then condensing the vapors.

5. Miscible liquids : Homogeneous liquid-liquid mixtures are called miscible liquids.

6. Immiscible liquids: Heterogeneous liquid-liquid mixtures are called immiscible liquids.

1. The process of separating different dissolved constituents of a mixture by their absorption on an appropriate material is called chromatography.

2. It is named so because earlier it was used to separate mixtures containing colored components only but these days this technique is applied to colorless substances too.

3. Advantages of chromatography :

(i) A very small quantity of the substance can be separated.

(ii) Components with very similar physical and chemical properties can be separated.

(iii) It identifies the different constituents of a mixture.

(iv) lt also helps in quantitative estimation of components of a mixture.

4. The simplest type of chromatography is “Paper chromatography”.

5. Chromatography is based on differential affinities of compounds towards two phases i.e. stationary and mobile phase.

6. The filter paper acts as “stationary phase” while the solvent act as “mobile phase”.

A pure liquid is obtained from a solution by distillation.

Example of a homogeneous mixture is :

tap water

A mixture of sand and ammonium chloride can be separated by sublimation.

In distillation and evaporation both the solution is allowed to boil by giving heat.

Evaporation does not involve the collection of vapor thus obtained. Distillation involves the condensation of the vapor obtained to obtain the pure solvent. This is done in a specially designed condensation chamber.

The advantage of distillation is that both components of the solid and liquid mixture are obtained. Whereas in evaporation only solid is obtained.

fractional distillation

Sodium is a metal that is stored in kerosene oil as it reacts very fast with air and water. Chlorine is a reactive greenish yellow gas which is poisonous. When these two elements combine chemically they form common salt sodium chloride which is non poisonous colourless solid substance that we use in our food to add taste and to obtain some nutrition.