Question:
Explain with an example what is a colloid?
Answer:
A colloid is intermediate between suspension and solution. A homogenous-looking heterogeneous mixture in which particles have size between 1 nm to 100nm (1 nano-m = 10-9 m) and are dispersed in a continuous medium is called a colloid. A Colloidal solution is also called a sol. The continuous medium in a sol is called the dispersion medium and the particles form the dispersed phase or colloidal particles. Examples of colloids are: milk, blood, toothpaste, jelly, fog, cloud etc.
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.
What are the properties of a colloid?
Q 3.
What are the physical states of dispersed phase and dispersion medium of a fog?
Q 4.
Choose one term from the following which includes the other three :
aerosol,
emulsion,
colloid,
sol
Q 5.
Name the property of any one of the components which can be used for separating the following mixture : Salt and Camphor
Q 6.
What is saturated solution? Explain with an example.
Q 7.
Classify the following as physical or chemical changes :
(i) Cooking of food
Q 8.
Name the process you would use to separate ammonium chloride from a mixture of sodium chloride and ammonium chloride.
Q 9.
Name one pair of liquids which can be separated by using a separating funnel.
Q 10.
What is meant by solute and solvent?
Q 11.
Name a metal which is soft and a non-metal which is hard.
Q 12.
What are aqueous solutions?
Q 13.
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 14.
What is a solution? What are the properties of a solution?
Q 15.
What are the various methods to express concentration of a solution?
Q 16.
How crystallization is better than evaporation?
Q 17.
Name the technique to separate
(i) butter from curd
(ii) salt from sea-water
(iii) camphor from salt
Q 18.
How much water should be mixed with 12 mL of alcohol so as to obtain 12 % alcohol solution ?
Q 19.
What are the characteristics of mixture?
Q 20.
What is an unsaturated solution?
Q 21.
What are the physical states of dispersed phase and dispersion medium of a cloud?
Q 22.
What are the reasons for separating the constituents of a mixture?
Q 23.
Name a non-metal which is a good conductor of electricity.
Q 24.
Name the property of one of the constituents which can be used to separate a mixture of salt and iodine
Q 25.
Name the source from which nitrogen and oxygen are obtained on a large scale.
Q 26.
What is meant by a pure substance?
Q 27.
On the basis of composition, how matter is classified?
Q 28.
What are non-aqueous solutions?
Q 29.
What are suspensions? Explain with an example.
Q 30.
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 31.
What are different ways to separate solid mixtures?
Q 32.
Define Brownian movement in colloids.
Q 33.
Identify the following as mixture or compound.
(i) blood
(ii) common salt
(iii) sugar
(iv) brass
Q 34.
What are pure substances ? Give two examples of pure substances.
Q 35.
(a) What is meant by (i) elements (ii) compounds, and (iii) mixtures ? Write down the names of two elements,two compounds and two mixtures.
(b) Classify the following into elements,
compounds and mixtures :
Marble,
Air,
Gold,
Brass,
Sand,
Diamond,
Graphite,
Petroleum,
Common salt,
Sea-water,
Chalk
Q 36.
Which of the following will show Tyndall effect ? Why ?
(a) Salt solution
(b) Starch solution
(c)Milk
Q 37.
What type of magnet is fitted on a crane to separate scrap iron objects from a heap of waste materials in factories ?
Q 38.
Name one pair of substances whose mixture can be separated completely by distillation.
Q 39.
Name the process which can be used to separate a mixture of salt solution and sand.
Q 40.
Name the process which is used in milk dairies to separate cream from milk.
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 kinds of mixture?
Q 43.
How elements are further classified?
Q 44.
State the differences between compounds and mixtures.
Q 45.
Why do fish go in deep waters during day light?
Q 46.
Based on the type of solvent, how solutions are classified?
Q 47.
Based on the amount of solute in the given solution, how solutions are classified?
Q 48.
What are the advantages of preparing solutions?
Q 49.
Explain with an example what is a colloid?
Q 50.
What is Chromatography?
