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NCERT solutions Science Textbook For Class 8 chapter 6 Combustion and Flame

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Chapter 6 - Combustion and Flame

Page 75

List conditions under which combustion can take place.

Q 1 | Page 75 |

Fill in the blanks:

Burning of wood and coal causes _______  of air.

Q 2.1 | Page 75 |

Fill in the blanks:

A liquid fuel used in homes is _________.

Q 2.2 | Page 75 |

Fill in the blanks:

Fuel must be heated to its __________ before it starts burning.

Q 2.3 | Page 75 |

Fill in the blanks:

Fire produced by oil cannot be controlled by ________ _

Q 2.4 | Page 75 |

Explain how the use of CNG in automobiles has reduced pollution in our cities.

Q 3 | Page 75 |

Compare LPG and wood as fuels.

Q 4 | Page 75 |

Give reasons

Water is not used to control fires involving electrical equipment.

Q 5.1 | Page 75 |

Give reasons

LPG is a better domestic fuel than wood.

Q 5.2 | Page 75 |

Give reasons.

Paper by itself catches fire easily whereas a piece of paper wrapped around an aluminium pipe does not.

Q 5.3 | Page 75 |

Make a labelled diagram of a candle flame.

Q 6 | Page 75 |

Name the unit in which the calorific value of a fuel is expressed.

Q 7 | Page 75 |

Explain how CO2 is able to control fires.

Q 8 | Page 75 |

It is difficult to burn a heap of green leaves but dry leaves catch fire easily. Explain

Q 9 | Page 75 |

Which zone of a flame does a goldsmith use for melting gold and silver and why?

Q 10 | Page 75 |

In an experiment 4.5 kg of a fuel was completely burnt. The heat produced was measured to be 180,000 kJ. Calculate the calorific value of the fuel.

Q 11 | Page 75 |

Can the process of rusting be called combustion? Discuss.

Q 12 | Page 75 |

Abida and Ramesh were doing an experiment in which water was to be heated in a beaker. Abida kept the beaker near the wick in the yellow part of the candle flame. Ramesh kept the beaker in the outermost part of the flame. Whose water will get heated in a shorter time?

Q 13 | Page 75 |

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