Science
Class 8th Test From Ch. 6 – Combustion And Flame
Total Marks: 30 Time: 30 minutes
Dated: 09/10/2010
Question 1: What are combustible substances?
Give two examples. (2 marks)
Question
2: State whether True or False.
(1 mark x 2 = 2marks)
(i) Fuel,
air and heat are not necessary for combustion.
(ii)
Stone and glass pieces are non-combustible.
Question
3: Choose the correct statement. (1 mark)
(i) If a
thick piece of dry wood is kept over a burning matchstick, it catches fire.
(ii) When
a paper cup containing water is heated over a candle flame, the paper does not
burn.
(iii)
Inflammable substances have high ignition temperature.
Question 4: Name the parts
labelled (i) and (ii) in the given figure of flame. (1 mark x 2 = 2 marks)
Question 5: Name the different
types of combustion. (1 mark x 3 = 3 marks)
Question
6: Fill in the blanks.
(1 mark x
4 = 4 marks)
(i)
Candle burns with a flame, but ________ does not.
(ii) A
chemical process in which a substance reacts with _______ to give off heat is
called combustion.
(iii)
Light is given off during combustion in the form of either ________ or
________.
Question 7: Why does not a
matchstick catch fire on its own at room temperature? (2 marks)
Question 8: How can fires
involving electrical equipments be controlled? Explain your answer. (2 marks)
Question
9: Match the following. (1 mark x 4 = 4 marks)
CNG
|
Respiratory
problem
|
Deforestation
|
Coal
mine, forest fire
|
Unburnt
carbon particles
|
Cutting
of trees
|
Spontaneous
combustion
|
Clean
fuel
|
Question
10: Explain the following (2 marks x 4 = 8 marks)
(i)
Characteristics of good fuel
(ii)
Calorific value and its unit
(iii)
Acid rain
(iv)
Global warming
