Assignment - Is Matter Around Us Pure, Class 9, Science PDF Download

FILL IN THE BLANKS :
1. Compound is a ............substance.
2. Wood is a .............
3. Electrolysis of water is a ............change.
4. Digestion of food is a............change.
5. ............is a metal which exists as liquid.
6. Gases can be separated from air by............method.
7. ............show tyndall effect.
8. Brass is a mixture of ............and ...............
9. 10% by mass of a solution means............g of solute are present in 50gm of solution.
10. Air is a.............

WRITE T FOR TRUE AND F FOR FALSE STATEMENT :
1. Steam is a compound.
2. Mercury is a liquid non-metal.
3. Mass percentage of a solution containing 10 g of solute in 100g of water is 10%.
4. Mixture of salt and ammonium chloride can be separated by cyrstallisaion process.
5. Constituents of a mixture can be separated by physical methods.
6. Milk, coffee and brass are example of mixtures.
7. Digestion of food is a physical change.
8. Solutions cannot be separated by the process of filtration.
9. Fog is an example of liquid dispersed in gas.

Q.1 What is the other name of impure substances ? Give two examples of impure substances.

Q.2 Name three mixtures found in nature.

Q.3 Which of the following is a mixture ? Salt, Air, Water, Alum, Sugar.

Q.4 A solution contains 80 g of common salt in 640 g of water. Calculate the concentration in terms of mass by mass percentage of the solution

Q.5 A solution contains 40g of acetic acid and 500 ml of aq. solution. What is the concentration of acetic acid solution?

Q.6 Out of a colloid, solution and a suspension :

(a) which one has the smallest particles. (b) which one has the largest particles ?

Q.7  Which of the two will scatter light : soap solution or sugar solution ? Why

Q.8 Which of the following will show Tyndall Effect ? Why

(a) Salt solution (b) Starch solution (c) Milk (d) Copper sulphate solution

Q.9 What is the concentration of a solution which contains 16g of urea in 120g of solution ? [13.3%]

Q.10 If 25mL of acetone is present in 150 mL of its aqueous solution, calcualte the concentration of solution.[16.6%]

Q.11  How will you separate a mixture containing kerosene and petrol (difference in their boiling points is
more than 25°C, which are miscible with each other ?

Q.12  Name the technique to separate

(i) butter from curd,

(ii) Salt from sea-water,

(iii) Camphor from salt

Q.13 What type of mixtures are separated by the technique of crystalisation ?

Q.14  Name the apparatus you would use to separate oil from water.

Q.15  You are given a mixture of water, groundnut oil and common salt. How will you separate grounnut oil
and common salt from it ?

Q.16  Name the property of one of the constituents which can be used to separate a mixture of salt and camphor.