Question:
Why do fish go in deep waters during day light?
Answer:
During day time, the shallow water is warmer and hence it has less dissolved oxygen. Therefore fish tend to go in deep water during day time.
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.
Choose one term from the following which includes the other three :
aerosol,
emulsion,
colloid,
sol
Q 3.
Name the property of any one of the components which can be used for separating the following mixture : Salt and Camphor
Q 4.
What are the physical states of dispersed phase and dispersion medium of a fog?
Q 5.
What are the properties of a colloid?
Q 6.
Name any two solid substances whose mixture can be separated by sublimation.
Q 7.
Name the property of one of the constituents which can be used to separate a mixture of salt and iodine
Q 8.
What is saturated solution? Explain with an example.
Q 9.
What is a solution? What are the properties of a solution?
Q 10.
What are aqueous solutions?
Q 11.
What are the physical states of dispersed phase and dispersion medium of a cloud?
Q 12.
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 13.
What are pure substances ? Give two examples of pure substances.
Q 14.
Classify the following as physical or chemical changes :
(i) Cooking of food
Q 15.
What is meant by solute and solvent?
Q 16.
What are suspensions? Explain with an example.
Q 17.
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 18.
How crystallization is better than evaporation?
Q 19.
Define Brownian movement in colloids.
Q 20.
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 21.
Name one pair of liquids which can be separated by using a separating funnel.
Q 22.
Name one pair of substances whose mixture can be separated completely by distillation.
Q 24.
When we open the cap of a cola drink (or any carbonated beverage), why does excess of bubbles come out?
Q 25.
What principle is applied in centrifugation? Give examples where this method is applied to separate mixtures.
Q 26.
What is an emulsion? Give examples
Q 27.
Give two reasons for supposing that water is a compound and not a mixture.
Q 28.
Fill in the following blanks :
(a)Milk is a.........solution but vinegar is a.......solution.
(b)A colloid is a........mixture and its components can be separated by the technique known as........
Q 29.
Name the process you would use to separate ammonium chloride from a mixture of sodium chloride and ammonium chloride.
Q 30.
On the basis of composition, how matter is classified?
Q 31.
What are the constituents of brass?
Q 32.
State the differences between compounds and mixtures.
Q 33.
What are non-aqueous solutions?
Q 34.
What is an unsaturated solution?
Q 35.
What are the reasons for separating the constituents of a mixture?
Q 36.
What is Chromatography?
Q 37.
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 38.
What is the general name of the materials which contain at least two pure substances and show the properties of their constituents ?
Q 39.
(a) What is meant by a solution ? Give two examples of solutions.
(b)What is a suspension ? Give two examples of suspensions.
(c)
Q 40.
(a) Name the process by which common salt is obtained from sea-water.
(b) Name the process by which common salt is purified.
Q 41.
Which technique can be used to detect and identify traces of poison present in the stomach wash of a person ?
Q 42.
What are the characteristics exhibited by a pure substance?
Q 43.
Name two properties of a substance to check its purity?
Q 44.
What are the kinds of mixture?
Q 45.
What factors affect the solubility of solvent and solute?
Q 46.
Based on the amount of solute in the given solution, how solutions are classified?
Q 47.
What do you mean by strength of the solution?
Q 48.
Describe sieving method.
Q 49.
Name the technique to separate
(i) butter from curd
(ii) salt from sea-water
(iii) camphor from salt
Q 50.
A good method to separate alum (phitkari) from impure samples is
(a) Filtration
(b) Sedimentaion
(c) Crystallization
(d) Sublimation
