Fill in blanks
1. Mixture contains two or more substances mixed physically.
2. Salt is obtained from seawater by the process called evaporation.
3. The method of separating seeds of paddy from its stalks is called threshing.
4. The sand from muddy water is separated by sieving.
5. The insoluble solid left on the filter paper is called residue.
B. Multiple choice questions
1. Which of the following is a mixture?
ans. Gold.
2. A bowl of dal mixed with wheat flour can be separated by
ans. sieving
3. A mixture of coconut oil and water can be separated by
ans. separating funnel
4. The property used in separating a mixture of two solids by winnowing is
ans. Difference in weight
5. The process of settling down of particles of a solid in a liquid is
ans. sedimentation
C. Very short answer questions. (ONE WORD)
1. Most substances around us are mixtures. TRUE.
2. Method used to separate wheat grains from chaff. Winnowing
3. Name the paper used in filtration Filter Paper.
4. Name the apparatus used to separate two immiscible liquids Separating Funnel
5. Solubility of substances in water increases with temperature. TRUE
D. Short answer questions.
1. Define:
a. sedimentation b. decantation c. filtration d. sieving
ans.
a. Sedimentation:-
The process of settling down of insoluble heavy particles in a solid-liquid mixture is called sedimentation.
b. Decantation:-
The process of pouring out the clear liquid without disturbing the sediments is called decantation.
c. Filtration:-
The process of separating insoluble solid component from a liquid using a filter paper is known as filtration.
d. Sieving:-
The process of separating components of different size from the mixture is known as sieving.
2. How would you separate peanuts from beans and why?
ans. Peanuts from beans can be separated by handpicking. Peanuts are small in pieces sometimes round or elongated in shape while beans are kidney shaped in structure slightly lighter than peanuts.
3. What is the principle used in the separation of components of mixtures?
ans. There are two main principles used in the separation of components of mixtures
(i) Separating solids from other solids:- Handpicking, threshing,winnowing, sieving come under this category.
(ii) Separating insoluble solids from liquid:- sedimentation, decantation,filtration, evaporation come under this category.
4. In what condition, sieving is used to separate components of a mixture?
ans. This method is used when the mixture contains components of different sizes.
5. What is saturated solution? How is it obtained?
ans. A solution which cannot dissolve any more of a substance at a particular temperature. This called saturated solution.
E. Long answer questions.
1. List some properties of mixture.
ans. Some properties of mixture are as under
(i) The components of mixture each keep their original properties.
(ii) The separation of components can easily be done.
(iii)The proportion of components is variable
2. Why is separation of mixtures necessary?
ans. Separation of mixture is necessary to get pure substances and the pure substances have
- Definite composition by nature.
- Definite physical properties such as melting point, boiling point and density.
- Homogeneous nature, e.g. elements like gold, silver, hydrogen and oxygen; compounds like copper sulfate or blue vitriol, water and sugar.
Most of the material found in nature are mixtures. Mixtures contain more than one substance which are mixed physically. In order to se the substances that we need,we have to separate the constituents of such mixtures.
3. Explain with the help of a diagram how can a mixture of oil and water can be separated?
(NOTE:-Make a diagram of separating funnel here)
ans. A mixture of oil and water can be separated with the help of separating funnel. Here are the procedure how you can do that.
Oil and water form two different lyres in the separating funnel as they are immisible liquids. Let it stand undisturbed for sometime. So that the separate layers of water and oil are formed. Now open the stopcock of the funnel and pour out of the lower layer of water carefully. In this way, water and oil can be separated using separating funnel.
4. What is difference between sediment and residue?
ans. The settling down of insoluble heavy solid components in a solid-liquid mixture is called sedimentation. and the solid particles that settle down during sedimentation are called sediments.
and the in soluble solid left on the filter is called residue.
5. How is winnowing done?
ans. Winnowing is the method of separating heavier and lighter components of a mixture b wind or by blowing air. In the method the mixture of chaff and grains is allowed to fall from a height. Grain being heaver, fall vertically down while chaff gets blown away and form a heap at a small distance away from the grains.
6. Explain with the help of a diagram, how will you separate a mixture of chalk powder and water using a filter paper.
ans.
- Take some water that is mixed with chalk water.
- Take a circular piece of filter paper and fold it twice as shown in the figure.
Filtration of chalk mixed water - Open the filter paper in such a way that one fold is on one side and other three folds on the other side. This forms a cone.
- Take a clean funnel and fit the folded filter paper cone in the funnel
- Keep a beaker below the funnel.
- Pour the chalk-powder mixed water slowly on the filter paper.
- Collect the filtrate in the beaker and observe.
You will find the chalk particles left behind on the filter paper and a clear filtrate in the beaker. Chalk particle form the residue.
For notes of other chapters (class VI), click on the heading of the chapters given below: Forward the links to as many students as you can..
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