Question:
Define Brownian movement in colloids.
Answer:
The colloidal particles move at random in a zigzag motion in all directions. This type of zig-zag motion of colloidal particles is called Brownian movement. It is caused due to the collision of the colloidal particles with the molecules of the dispersion medium. VIDEO
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 meant by solute and solvent?
Q 9.
What are aqueous solutions?
Q 10.
What is saturated solution? Explain with an example.
Q 11.
What are the physical states of dispersed phase and dispersion medium of a cloud?
Q 12.
What are pure substances ? Give two examples of pure substances.
Q 13.
Classify the following as physical or chemical changes :
(i) Cooking of food
Q 14.
On the basis of composition, how matter is classified?
Q 15.
What is a solution? What are the properties of a solution?
Q 16.
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 18.
What are suspensions? Explain with an example.
Q 19.
What principle is applied in centrifugation? Give examples where this method is applied to separate mixtures.
Q 20.
How crystallization is better than evaporation?
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 23.
What are the constituents of brass?
Q 24.
When we open the cap of a cola drink (or any carbonated beverage), why does excess of bubbles come out?
Q 25.
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 26.
What are the reasons for separating the constituents of a mixture?
Q 27.
Define Brownian movement in colloids.
Q 28.
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 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.
Give two reasons for supposing that water is a compound and not a mixture.
Q 32.
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 33.
Name two properties of a substance to check its purity?
Q 34.
State the differences between compounds and mixtures.
Q 35.
Why air is a mixture not a compound? Give reasons.
Q 36.
What is an unsaturated solution?
Q 37.
Explain with an example what is a colloid?
Q 38.
What is Chromatography?
Q 39.
State whether the following statement is true or false : Milk is a pure substance.
Q 40.
(a) What is meant by a solution ? Give two examples of solutions.
(b)What is a suspension ? Give two examples of suspensions.
(c)
Q 41.
Name the process you would use to separate ammonium chloride from a mixture of sodium chloride and ammonium chloride.
Q 42.
Name one pair of substances whose mixture can be separated by fractional distillation.
Q 43.
Name the process which can be used to separate a mixture of salt solution and sand.
Q 44.
(a) Name the process by which common salt is obtained from sea-water.
(b) Name the process by which common salt is purified.
Q 45.
Which technique can be used to detect and identify traces of poison present in the stomach wash of a person ?
Q 46.
How will you separate iron pins from sand ?
Q 47.
What are the characteristics exhibited by a pure substance?
Q 48.
What are the kinds of mixture?
Q 49.
Based on the type of solvent, how solutions are classified?
Q 50.
What are non-aqueous solutions?
