Question:
What are the properties of a colloid?
Answer:
Properties of a colloid are:
- Heterogeneous nature: Colloid or Sol is heterogeneous in nature i.e. it can be seen only with a powerful microscope.
- Particle Size: Colloid particle size lies between 1nm (10-9 m) to 100 nm (10-7 m)
- Separation of colloidal particles by filtration: Colloidal particles cannot be separated from the mixture by the process of filtration. But, a special technique of separation known as centrifugation.
- Brownian Motion: When seen under microscope, the colloidal particles in a colloid are seen to be moving in a random fashion, called Brownian motion.
- Stability: They do not settle down when left undisturbed, that is, a colloid is quite stable.
- Tyndall effect: Colloid exhibit Tyndall effect. When a light is passed through sol kept in dark room, the path of light beam is visible. It is due to scattering of light by colloidal particles and this effect is called Tyndall effect.
- Electrophoresis: Man colloidal particles may have electrical charge (+ve or -ve) on them. When an electric current passes through a sol, colloid particles move towards opposite charged electrodes. This process is called electrophoresis.
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.
Name any two solid substances whose mixture can be separated by sublimation.
Q 6.
What are the properties of a colloid?
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.
Classify the following as physical or chemical changes :
(i) Cooking of food
Q 13.
On the basis of composition, how matter is classified?
Q 14.
What is a solution? What are the properties of a solution?
Q 15.
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 16.
What are pure substances ? Give two examples of pure substances.
Q 17.
What are suspensions? Explain with an example.
Q 18.
What principle is applied in centrifugation? Give examples where this method is applied to separate mixtures.
Q 19.
How crystallization is better than evaporation?
Q 20.
Name one pair of liquids which can be separated by using a separating funnel.
Q 21.
Name one pair of substances whose mixture can be separated completely by distillation.
Q 23.
When we open the cap of a cola drink (or any carbonated beverage), why does excess of bubbles come out?
Q 24.
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 25.
What are the reasons for separating the constituents of a mixture?
Q 26.
Define Brownian movement in colloids.
Q 27.
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 28.
What is an emulsion? Give examples
Q 29.
What is the general name of the materials which contain at least two pure substances and show the properties of their constituents ?
Q 30.
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 31.
Name two properties of a substance to check its purity?
Q 32.
What are the constituents of brass?
Q 33.
State the differences between compounds and mixtures.
Q 34.
Why air is a mixture not a compound? Give reasons.
Q 35.
What is an unsaturated solution?
Q 36.
Explain with an example what is a colloid?
Q 37.
What is Chromatography?
Q 38.
Give two reasons for supposing that water is a compound and not a mixture.
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.
Name the process you would use to separate ammonium chloride from a mixture of sodium chloride and ammonium chloride.
Q 41.
Name one pair of substances whose mixture can be separated by fractional distillation.
Q 42.
Name the process which can be used to separate a mixture of salt solution and sand.
Q 43.
(a) Name the process by which common salt is obtained from sea-water.
(b) Name the process by which common salt is purified.
Q 44.
How will you separate iron pins from sand ?
Q 45.
What are the characteristics exhibited by a pure substance?
Q 46.
What are the kinds of mixture?
Q 47.
Based on the type of solvent, how solutions are classified?
Q 48.
What are non-aqueous solutions?
Q 49.
How are sol, solution and suspension different from each other?
Q 50.
What do you mean by strength of the solution?
