Question:
What are suspensions? Explain with an example.
Answer:
A suspension is a heterogeneous mixture in which very fine particles (about 10-5 m size) of solid are dispersed in any medium (liquid or gas). In suspension, the solute particles are visible to the naked eye, and remain suspended throughout the bulk of the medium. The Tyndall effect is observed in this mixture. Muddy pond water, smoke coming out of a chimney, chalk-water mixture, coarse lime particles in water are examples of suspension.
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 substances whose mixture can be separated by fractional distillation.
Q 5.
Name one pair of liquids which can be separated by using a separating funnel.
Q 6.
Define Brownian movement in colloids.
Q 7.
What is saturated solution? Explain with an example.
Q 8.
Calculate the mass of glucouse and mass of water required to make 200g of 25% solution of glucouse.
Q 9.
Give two reasons for supposing that water is a compound and not a mixture.
Q 10.
What is the concentration of a solution which contains 16 g of urea in 120 g of solution ?
Q 11.
What type of magnet is fitted on a crane to separate scrap iron objects from a heap of waste materials in factories ?
Q 12.
Name the property of one of the constituents which can be used to separate a mixture of salt and iodine
Q 13.
Name the process which can be used to separate a mixture of salt solution and sand.
Q 14.
State the differences between compounds and mixtures.
Q 15.
What are non-aqueous solutions?
Q 16.
What is an unsaturated solution?
Q 17.
How are sol, solution and suspension different from each other?
Q 18.
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 19.
Name a non-metal which is a good conductor of electricity.
Q 20.
Name the property :
(a) which allows metals to be hammered into thin sheets.
(b)
Q 21.
What is meant by saying that metals are malleable and ductile ?
Q 22.
Name the process you would use to separate ammonium chloride from a mixture of sodium chloride and ammonium chloride.
Q 23.
Which technique can be used to detect and identify traces of poison present in the stomach wash of a person ?
Q 24.
What are different categories of pure substance?
Q 25.
Give examples of liquids that are
(i) completely miscible
(ii) partially miscible
(iii) practically immiscible
Q 26.
What is the general name of the materials which contain at least two pure substances and show the properties of their constituents ?
Q 27.
Which of the two will scatter light: soap solution or sugar solution ? Why ?
Q 28.
How much water should be mixed with 12 mL of alcohol so as to obtain 12 % alcohol solution ?
Q 29.
Name the property of any one of the components which can be used for separating the following mixture : Salt and Camphor
Q 30.
Name the source from which nitrogen and oxygen are obtained on a large scale.
Q 31.
Name the process which is used in milk dairies to separate cream from milk.
Q 32.
How is cream separated from milk ?
Q 34.
Explain with an example what is a colloid?
Q 35.
What are different ways to separate solid mixtures?
Q 36.
Who used the term 'element' first time?
Q 37.
Identify the following as mixture or compound.
(i) blood
(ii) common salt
(iii) sugar
(iv) brass
Q 38.
State whether the following statement is true or false : Milk is a pure substance.
Q 39.
Which of the following is a mixture ?Salt, Air, Water, Alum, Sugar
Q 40.
Classify the following into elements and compounds :
(i)
Q 41.
Name the process you would use to separate a mixture of anthracene and copper sulphate ?
Q 42.
Name the process by which the various gases of the air are separated.
Q 43.
Name any two solid substances whose mixture can be separated by sublimation.
Q 44.
What are the characteristics of mixture?
Q 45.
What is meant by solute and solvent?
Q 46.
Why do fish go in deep waters during day light?
Q 47.
Why air is a mixture not a compound? Give reasons.
Q 48.
Winnowing works on what property?
Q 49.
Name the elements are in liquid state at room temperature.
Q 50.
What are the differences and similarities between concentration and solubility?
