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.
How much water should be added to 15 grams of salt to obtain 15 per cent salt solution ?
Q 3.
Classify the following as physical or chemical changes :
(i) Cooking of food
Q 4.
Name one pair of liquids which can be separated by using a separating funnel.
Q 5.
Name one pair of substances whose mixture can be separated by fractional distillation.
Q 6.
What type of magnet is fitted on a crane to separate scrap iron objects from a heap of waste materials in factories ?
Q 7.
Name the property :
(a) which allows metals to be hammered into thin sheets.
(b)
Q 8.
Give two reasons for supposing that water is a compound and not a mixture.
Q 9.
What are non-aqueous solutions?
Q 10.
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 11.
Calculate the mass of glucouse and mass of water required to make 200g of 25% solution of glucouse.
Q 12.
Name a non-metal which is a good conductor of electricity.
Q 13.
Name the property of any one of the components which can be used for separating the following mixture : Salt and Camphor
Q 14.
Which technique can be used to detect and identify traces of poison present in the stomach wash of a person ?
Q 15.
What is saturated solution? Explain with an example.
Q 16.
Define Brownian movement in colloids.
Q 17.
Which of the following is a mixture ?Salt, Air, Water, Alum, Sugar
Q 18.
How much water should be mixed with 12 mL of alcohol so as to obtain 12 % alcohol solution ?
Q 19.
What is the concentration of a solution which contains 16 g of urea in 120 g of solution ?
Q 20.
Name the process which can be used to separate a mixture of salt solution and sand.
Q 21.
State the differences between compounds and mixtures.
Q 22.
What are different ways to separate solid mixtures?
Q 23.
Identify the following as mixture or compound.
(i) blood
(ii) common salt
(iii) sugar
(iv) brass
Q 24.
State whether the following statement is true or false : Milk is a pure substance.
Q 25.
What is the general name of the materials which contain at least two pure substances and show the properties of their constituents ?
Q 26.
Name the process you would use to separate ammonium chloride from a mixture of sodium chloride and ammonium chloride.
Q 27.
Name the property of one of the constituents which can be used to separate a mixture of salt and iodine
Q 28.
Name the source from which nitrogen and oxygen are obtained on a large scale.
Q 29.
Name the apparatus you would use to separate oil from water.
Q 30.
What are different categories of pure substance?
Q 31.
What are the kinds of mixture?
Q 32.
What is meant by solute and solvent?
Q 33.
What are the physical states of dispersed phase and dispersion medium of a cloud?
Q 34.
How are sol, solution and suspension different from each other?
Q 35.
Winnowing works on what property?
Q 36.
Name the elements are in liquid state at room temperature.
Q 37.
Who used the term 'element' first time?
Q 38.
Give examples of liquids that are
(i) completely miscible
(ii) partially miscible
(iii) practically immiscible
Q 39.
What is meant by saying that metals are malleable and ductile ?
Q 40.
What are pure substances ? Give two examples of pure substances.
Q 41.
(a) What is a physical change ? Give two examples of physical changes.
(b) What is a chemical change ? Give two examples of chemical changes.
Q 42.
Name any two solid substances whose mixture can be separated by sublimation.
Q 43.
Name the process you would use to separate a mixture of water and alcohol.
Q 44.
How is cream separated from milk ?
Q 46.
What is a compound? Give an example.
Q 47.
What is a solution? What are the properties of a solution?
Q 48.
What is an unsaturated solution?
Q 49.
Explain with an example what is a colloid?
Q 50.
What are the properties of a colloid?
