Friday, 19 August 2016

CLASS 9 REVISION
1. Neha's mother is a good cook.She uses natural colours to give colours to different foods.She uses turmeric for yellow colour, spinach for green colour and pomegranate for red colour.She avoids synthetic colours.Answer the following questions based on the above information

(a) Name the technique used to separate pigments from natural colours.
(b) Name the  principle of that technique.
(c) Explain the values that are displayed by Neha's mother

2, Define evaporation.Out of nylon and cotton cloth, which is more comfortable.Why?
   Is evaporation and boiling same? if not , Why?

3. Give one example where both chemical and physical change take place together?

4.A solution contains 30g of glucose, 20g of sugar in 500g of water. Calculate the mass percentage of glucose and sugar respectively?

5 A given substance X has definite volume, no fixed shape and can diffuse well. What is the physical state of substance X?

.MCQ'S

1.. The sequence of steps taken for separating a mixture of ammonium chloride , sand and common salt is :
: a) sublimation, adding water, filtration , evaporation
 b) evaporation , adding water , filtration, sublimation
c) filtration , evaporation , sublimation , adding water
d) adding water , evaporation , sublimation , filtration

 2. A student takes some water in a beaker and heats it over a flame for determining the boiling point. He keeps on taking its temperature readings. He would observe that the temperature of water

a) keeps on increasing regularly
 b) keeps on increasing irregularly
 c) first increases slowly , then decreases rapidly and eventually becomes constant
 d) first increases gradually and then becomes constant

 3. The layer deposited on iron nails dipped in copper sulphate solution is a) iron b) copper c) sulphur d) oxygen

4.The gas which evolves when zinc reacts with dil. Sulphuric acid
a) helps to light a glowing splinter into flame
 b) gives a pop sound with lighted match stick
c) extinguishes a lit candle brought near it d) none of the above

5. To prepare a colloidal solution of starch , we should
a) add starch in boiling water and cool
b) add starch to cold water and boil
c) heat starch powder , add cold water and then bring to boil
d) add a thin paste of starch in boiling water while stirring

 6. From which one of the following, its components can be separated by filtration
 a) common salt+ water b)sugar + water c)soil + water d)starch + water

7 . A mixture of iron fillings and sulphur is a
a) homogeneous mixture b) heterogeneous mixture c) true solution d) sol

8. When a mixture containing iron fillings and sulphur powder is treated with carbon disulphide
a) Sulphur dissolves in it
b) iron dissolves in it
 c) both sulphur and iron dissolves
 d) no change

9 . A mixture has the following properties 1) the solution is hazy 2 )the particles are suspended in the solution 3) it shows Tyndall effect. The mixture is a
a) True solution b)colloid b) Suspension d) none of these

10. Rahul was rushing with a bottle of iodine , some iodine solution splashed on his white cotton shirt and also on the white table cloth. The stain on the table cloth was yellowish brown while that on his shirt was blue black. The most possible reason is that
a) Shirt was starched after washing
 b) table cloth was starched but not the shirt
 c) shirt has absorbed sweat
d) table cloth had oil patches

11. Following are 5 steps for testing metanil yellow in arhar dal
 i. Make powder of 5 gm of arhar dal
ii. put dal powder in a test tube
iii. add 2-4 drops of conc. HCl and observe the colour change
 iv. filter the content and keep the filtrate separately
v. add 10 ml of water and shake it well the correct sequence is
 a) i,ii,iii,iv,v b) I,iv,v,ii, iii c) I,iii,iv,v,ii









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