Question:
What are the characteristics of mixture?
Answer:
1. Variable composition: The constituents of a mixture are present in any ratio. Example: A mixture of sand and salt can be in a ratio of 1:2 or 1:3 by weight.
2. Only Physical change: The mixture is a result of physical change. The constituents of a mixture do not bind each other by chemical bonds. Example: In air the main constituents, i.e., oxygen, nitrogen and carbon dioxide, do not bind each other with chemical bonds.
3. No specific properties: The properties of a mixture are the average of the properties of its constituents. Example: The properties of air are average common properties of nitrogen and oxygen.
4. Homogeneity: Most of the mixtures are heterogeneous, i.e., their constituents are not spread evenly throughout. However, some mixtures are homogeneous i.e. constituents are uniformly spread out. Example: In the mixture of iron and sulphur, at some places iron is more and at some places sulphur is more.
5. Separation Methods: In general, the constituents of mixture can be separated by applying suitable physical methods. E.g. Iron can be separated from the mixture of iron and sulphur with the help of a magnet.
6. Energy changes: In general, no energy is released or absorbed during the formation of a mixture. Example: On mixing iron and sulphur, heat energy is neither absorbed nor evolved.
Is Matter Around Us Pure?
Q 1.
What is the general name of the process by which tea-leaves are separated from prepared tea ?
Q 2.
Name the property of any one of the components which can be used for separating the following mixture : Salt and Camphor
Q 3.
Choose one term from the following which includes the other three :
aerosol,
emulsion,
colloid,
sol
Q 4.
Name any two solid substances whose mixture can be separated by sublimation.
Q 5.
What are the physical states of dispersed phase and dispersion medium of a fog?
Q 6.
What are the properties of a colloid?
Q 7.
What are aqueous solutions?
Q 8.
What is saturated solution? Explain with an example.
Q 9.
What are the physical states of dispersed phase and dispersion medium of a cloud?
Q 10.
A solution contains 40 mL of ethyl alcohol mixed with 100mL of water. What is the concentration of the solution in terms of volume by volume percentage?
Q 11.
What are pure substances ? Give two examples of pure substances.
Q 12.
Classify the following as physical or chemical changes :
(i) Cooking of food
Q 13.
Name one pair of liquids which can be separated by using a separating funnel.
Q 14.
What is a solution? What are the properties of a solution?
Q 15.
How crystallization is better than evaporation?
Q 16.
Define Brownian movement in colloids.
Q 17.
Give two reasons for supposing that water is a compound and not a mixture.
Q 18.
Name the process you would use to separate ammonium chloride from a mixture of sodium chloride and ammonium chloride.
Q 20.
What is meant by solute and solvent?
Q 21.
When we open the cap of a cola drink (or any carbonated beverage), why does excess of bubbles come out?
Q 22.
What are suspensions? Explain with an example.
Q 23.
To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water at 293K. Find its concentration at this temperature.
Q 24.
What principle is applied in centrifugation? Give examples where this method is applied to separate mixtures.
Q 25.
Name the following :
(a) a lustrous liquid metal.
(b) a liquid non-metal
(c) a metal which can be cut with a knife
(d) a non-metal which is good conductor of electricity.
(e) an element which melts when kept on the palm.
(f) the best conductor of heat.
Q 26.
Name the property of one of the constituents which can be used to separate a mixture of salt and iodine
Q 27.
What is an unsaturated solution?
Q 28.
What is Chromatography?
Q 29.
What is an emulsion? Give examples
Q 30.
What is the general name of the materials which contain at least two pure substances and show the properties of their constituents ?
Q 31.
What are the characteristics exhibited by a pure substance?
Q 32.
On the basis of composition, how matter is classified?
Q 33.
Name two properties of a substance to check its purity?
Q 34.
What are the kinds of mixture?
Q 35.
State the differences between compounds and mixtures.
Q 36.
What are non-aqueous solutions?
Q 37.
Explain with an example what is a colloid?
Q 38.
What are the reasons for separating the constituents of a mixture?
Q 39.
In beaker A, sugar cubes are dissolved into water while in beaker B, crushed cubes are taken. In which beaker the rate of dissolution is faster?
Q 40.
Name a non-metal which is a good conductor of electricity.
Q 41.
(a) What is meant by a solution ? Give two examples of solutions.
(b)What is a suspension ? Give two examples of suspensions.
(c)
Q 42.
Name the source from which nitrogen and oxygen are obtained on a large scale.
Q 43.
Name one pair of substances whose mixture can be separated completely by distillation.
Q 44.
List the points of differences between homogeneous and heterogeneous mixtures.
Q 45.
What are the constituents of brass?
Q 46.
Why do fish go in deep waters during day light?
Q 47.
Based on the amount of solute in the given solution, how solutions are classified?
Q 48.
Why air is a mixture not a compound? Give reasons.
Q 49.
What are the properties of suspensions?
Q 50.
What do you mean by strength of the solution?
