A.Tick the correct answer:-

 1a.      2a.       3a.    4c.  

B.Differentiate between the following:-

 1. Evaporation is heating a substance to gaseous form and then cooling that to its former state is called condensation.

2. When an insoluble solid in a liquid is allowed to stand for a long time, the insoluble substance settle at the bottom, this when allow to pour on a filter paper placed over a funnel. This process is decantation. The residne we obtain on filter paper and filtrate. This process is called filtration.

3. The crop which is obtained from agriculture field is hold on hand and is beaten on ground to obtain crop. This is called thereshing. Crop mixed with ctaff is placed near  wind where by chaff is separated from crop .This process is called winnowing.

4. In the forces of filtration the clear liquid that passes out of filter paper is called filtrate; while the insoluble solid that left on the filter paper is known as residue.

C.Give one word answer for each of the following:-

 1. Solute         2.  Vapourisation.

   3. Solubility.    4. Threshing.

D.Match column A with column b:-

 1.-------->.  Pure substance. 

    2. -------->. Homogeneous.

    3. ---------> combine harvester.

    4. ----------> heterogeneous.

    5. -----------> mixture of metal.

E.Give two nexamples for each of the following:-

 1. Dry clothes, To purify water 

    2. Air, perfume.

    3. Rainwater, diamond.

    4. Petroleum, coal

F.Give reasons each of the following:-

1. We separate mixture to get its individual component.

2. Different methods are used according to the nature of mixtures.

3. Because pure substance is one which is made up of one kind of substance.

4. Because wind in winnoing separate contituents according to their density.

5. Because mixture of sugar and water is clear liquid and we will not get any residue on filter paper.

G.Write true or false:-

 1.False     2.False     3.False.     4False.   

H.Circle the odd one out:-

 1. Sedimentation.      2. Smoke

     3. Water.                     4. Aluminium

I.Fill in the blanks:-

1.Decantation         2.  Chaff 

3.  Soluble substance.    4. Water.

J.Short answer question:-

1.A mixture is a combination of two or more substance which mixed together without any chemical reaction it is two types:- 

a. Homogeneous.     b.  Heterogeneous.

2. Sedimentation, decantation and filtration.

3. By a separating funnel.

4. Loading is used to separate suspended impurities. Loading is a process in which chemical substance like alum is added to liquid to help suspended liquid to form a sediment.

5. A mixture of iron and sulphur

K.Long Answer question

1.  Sedimentation:- The method of allowing an insoluble, heavy solid mixed with a liquid to settle at the  bottom of the liquid is called sedimentation. While the process of separating the liquid from the top disturbing the sediment in is called decantation.

Filtration:- Another method of removing insoluble solid impurities present in a liquid in filtration. By this method   the separation is effected more completely then in the other process, and insoluble solid both heavier and lighter than a liquid, can be removed. In the laboratory filtration is ordinarily effected by pouring the liquid down a glass rod into a circular piece of filter paper. The clear liquid that passes out of the filter paper is called filtrate while the substance left is known as residue.

Distillation:- It is the process of converting a liquid first into his vapour and then condensing the vapour into the same liquid

Crystallization:- When the hot solution of a solid in a liquid is allowed to cool down, it is formed that a quantity of the solid, held in solution is deposited as a particle of geometric shape . This the process is known as crystallization.

Centrifugation:- The process in which the centrifugal force is used for sedimentation of heterogeneous mixture with the centrifuge is called centrifugation. For example to separate cream from milk.

2. Decantation:- The method consists in allowing an insoluble heavy solid, held in suspension in a liquid to settle at the bottom (sedimentation) and then carefully pouring of as much as of clear supernatant liquid as possible. example the coarse particles of sand in muddy water can be separated by decantation. 

          Before cooking, rice pulse etc are washed with water and separated by decantation.

3. A homogeneous mixture is a mixture where the components that make up the mixture are uniformly distinguish throughout the mixture i.e the composition of the mixture is uniform throughout In homogeneous  mixture the components cannot be seen with ordinary eyes or by using a magnifying glass. Air in a homogeneous mixture of several gases such as oxygen, nitrogen etc.

      A heterogeneous mixture is simply any mixture that is not uniform in composition. In a heterogeneous mixture the component can be seen by ordinary eye or through a microscope for example salad etc. Soil is a mixture of sand clay various salt and remains of plant or animals.

4. Such liquid which mix up throughly are called miscible liquid eg:- water and milk, kerosine and petrol also mixup thoroughly.

       Immiscible liquids are in capable of being mixed or blended together. Even when shaken together then finally separated into layers. Oil and water are immiscible.

       It is very different to separate out miscible liquid, while immiscible liquid can easily be separated. One of the immiscible liquid may be heavier than the other. Therefore when they are put together they soon separate out in two distinct layer. The upper layer is of the lighter liquid, while the lower layer is of the heavier liquid.

5. Threshing:- The process used to separate grain from the stalks is called threshing. In threshing the stalks are beaten against any hand surface such as large rocks or a stone slab etc to free the grains.

      Threshing is also done with the help of machines. Large quantities of stalks are put into a machine called thresher to obtain grains more easily.