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Saturday, July 2, 2011

Class 8 MCQs on Combustion and Flame,

1. In the presence of water, ignition Temperature of paper is-
a. Decrease                              b. Increase
c. Remain constant                  d. None of these
Ans.  (b)
2.The lowest temperature at which a Substance catches fire is called its-
a. Boiling point                                   b. Melting point
c. Ignition temperature                        d. Critical temperature
Ans.(c)
3.Which of the following is inflammable Substances?
a. Petrol                                   b. Wood
c. Paper                                   d. Straw
Ans.(a)
4.  Essential requirements for producing fire are:
a. Fuel                                     b. Air
c. Heat                                     d. All of these
Ans. (d)
5. Fire extinguisher-
a. Cut off the supply of air     b. Bring down the temperature of fuel
c. Both (a) & (b)                      d. None of these
Ans.(c)
6.  Rapid combustion is
a. When gas burns, it produces heat and light            b. When material suddenly burst into flames
c. When there is evolution of heat                  d. None of these
Ans.(a)
7. Explosion is the evolution of
a. Heat                                                             b. light
c. Sound                                                          d. All of these
Ans.(d)
8. Substance which vaporise during Burning gives
a. Sound                                                          b. Flame
c. Combustion                                                 d. None of these
Ans. (b)
9. Which is the hottest part in the flame of the candle
a. Blue                                                             b. Yellow
c. Black                                                                       d. Wax part
Ans. (a)
10. Innermost zone of candle flame  is the
a. Hottest part                                                 b. Moderately hot part
c. Least hot part                                              d. Cold part
Ans. (c)
11. Yellow colour in the cande  flame denotes
a. Outermost part                                            b. Middle zone
c. Innermost zone                                            d. None of these
Ans.(b)
12. Good fuel is
a. Readily available                                         b. Cheap
c. Burn easily in air                                         d. All of these
Ans.(d)
13. On burning fuel produces….. amount of heat
a. Large                                                           b. Less
c. Very less                                                      d. No heat
Ans.(a)
14. Use of ….. in vehicle reduces pollution
a. Petrol                                                           b. Diesel
c. CNG                                                                        d. None of these
Ans.(c)
15. Ideal fuel has ____ calorific value
a. Low                                                 b. High
c. Moderate                             d. Zero
Ans. (b)
16. Calorific value is measured in
a. Kilo joule                             b. Kilograms
c. Kilo joule per Kg                 d. Kilometre
Ans.(c)
17. Unburnt carbon particles causes
a. Stomach infections              b. Respiratory problems
c. Brain infections                   d. Throat problems
Ans.(b)
18. Incomplete combustion gives
a. CO2                                     b. CO
c. Carbon                                 d. None of these
Ans.(b)
19.  Goldsmith uses ____part of the flame for melting gold
a. Outermost                           b. Middle
c. Innermost                            d. Both (b) & (c)
Ans. (a)
20. Burning of coal and diesel releases 
a. NO2                                                b. CO2
c. SO2                                     d. CO
Ans.(c)
21. Petrol engine gives off gaseous oxides of
a. Sulphur                                b. Nitrogen
c. Phosphorous                                    d. Carbon

Ans.(b)
22. Acid rain is caused by oxides of
a. Sulphur, Nitrogen                b. Sulphur, Carbon
c. Carbon, Nitrogen                d. Phosphorous, Carbon
Ans.(a)
23. In the sun, heat and light are produced by
a. Chemical reactions              b.Nuclear reactions
c.Ionic reactions                      d.None of these
Ans.(b)
24. The head of the safety matchsticks contains
a. Antimony disulphide                      b Potassium Chlorate
c. Both (a) and (b)                   d. None of these
Ans.(c)
25. When the matchsticks  struck against rubbing surface, red phosphorous
a. Converts into white phosphorous   b. Reacts with potassium chlorate
c. Ignite antimony disulphide             d. None of these
Ans.(a) 

3 comments:

J.Sunil Sir said...

CHEMISTRY VIII 8th Combustion and Flame Assignment /Worksheet
http://chemistryadda.blogspot.in/2012/08/chemistry-7th-combustion-and-flame.html

Unknown said...

Thank you very much it was very useful for me..... 👏👏😄👌

Unknown said...

good sir

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