Whose water will get heated in a shorter time? Ramesh kept the beaker in the outermost part of the flame. Abida kept the beaker near the wick in the yellow part of the candle flame. So we can call the process of rusting as slow combustion.ДЄbida and Ramesh were doing an experiment in which water was to be heated in a beaker.

The process of rusting emits heat during the formation of its oxide. Calculate the calorific value of the fuel.Д¬alorific value of a fuel = H e a t P r o d u c e d A m o u n t o f f u e lД¬an the process of rusting be called combustion? Discuss. The heat produced was measured to be 180,000 kJ. In an experiment, 4.5 kg of a fuel was completely burnt. Which zone of a flame does a goldsmith use for melting gold and silver and why?ДЄ goldsmith uses the outermost zone of a flame, which is non-luminous, to melt gold and silver as it is the hottest zone of the flame, having more temperature. On the other hand, dry leaves are waterless, so they catch fire easily (having low ignition temperature). The green leaves hold some amount of water, so its ignition temperature gets increased and it does not burn easily. It is difficult to burn a heap of green leaves but dry leaves catch fire easily. In these ways, it plays a significant role in controlling fire. Men over, it brings down the temperature of the burning substance. The unit in which the calorific value of a fuel is expressed is kilojoules per kilogram (kJ/kg).Д®xplain how CO2 is able to control fires.ДЄs CO2 is heavier than oxygen, it forms a blanket around fire, because of which the supply of air is stopped.

Name the unit in which the calorific value of a fuel is expressed. Make a labelled diagram of a candle flame. But a piece of paper wrapped around an aluminium pipe does not catch fire easily, as the heat being given gets absorbed by the aluminium pipe and the piece of paper does not get its ignition temperature. (c) As its ignition temperature is low, the paper by itself catches fire easily. Moreover, it has more calorific value than wood. (b) LPG is better domestic fuel than wood because it does not produce gases, nor does it leave any residue behind. (a) Since water is a good conductor of electricity, it may result in electric shocks to the person trying to extinguish fire. (c) Paper by itself catches fire easily whereas a piece of paper wrapped around an aluminium pipe does not. (b) LPG is a better domestic fuel than wood. (a) Water is not used to control fires involving electrical equipment. (v) It canвЂ™t be transported easily like LPG fuels. (v) It can be easily transported, as it is stored in cylinders.

(iv) It has less calorific value (17000 kJ/kg). (iv) It has more calorific value (55000 kJ/kg). (i) It does not cause pollution on combustion. (b) It leaves behind no residue after its combustion. (a) It gives out less carbon dioxide gas, carbon monoxide gas, sulphur dioxide and nitrogen dioxide, which is beneficial as they play crucial role in global warming and acid rain. The use of CNG in automobiles has reduced pollution in our cities as it is a quality fuel and has some benefits: (d) Fire produced by oil cannot be controlled by _Д®xplain how the use of CNG in automobiles has reduced pollution in our cities. (c) Fuel must be heated to its _ before it starts burning. (a) Burning of wood and coal causes _ of air. (c) attainment of ignition temperature of the substance. (b) oxygen, that is, the supporter of combustion. List conditions under which combustion can take place.Д¬ombustion can take place in the presence of: Topics and Sub Topics in Class 8 ScienceВ Chapter 6 Materials combustion and flame: Section NameД¬ombustion and Flame Class 8 Science NCERT Textbook Questions NCERT Solutions for Class 8 Science Chapter 6 Combustion and Flame

Midiman oxygen 8 can it still be used