Answer: Although the process of rusting also involves oxidation but it cannot be termed as combustion. The reason for this is that combustion is defined as a process in which oxidation is accompanied by heat, and heat is not produced during rusting.
Question 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? Answer: Since Abida has kept the beaker in the luminous zone of the flame, the beaker will take more time to get heated.
On the other hand, Ramesh has kept the beaker in the non-luminous zone of the flame so his beaker will be heated in shorter time. Answer: Following are the conditions under which combustion can take place: Presence of oxygen Presence of inflammable substance Ignition temperature Question 2: Fill in the blanks: Burning of wood and coal causes ………………. A liquid fuel, used in homes is ……………….
Fuel must be heated to its ………………. Fire produced by oil cannot be controlled by ………………… Answer: a pollution, b kerosene, c ignition temperature, d water Question 3: Explain how the use of CNG in automobiles has reduced pollution in our cities.
Question 4: Compare LPG and wood as fuels. Question 5: Give reasons: a Water is not used to control fires involving electrical equipment. Question 6: Make a labelled diagram of a candle flame. Answer: Question 7: Name the unit in which the calorific value of a fuel is expressed.
Ncert solutions. Book a free class now. Combustion and Flame Exercise. Crop Production and Management 2. Microorganisms: Friend and Foe 3. Synthetic Fibres and Plastic 4. Materials: Metals and Non-Metals 5. Coal and Petroleum 6. Combustion and Flame 7.
Conservation of Plants and Animals 8. Cell — Structure and Functions 9. Reproduction in Animals Reaching the Age of Adolescence Force and Pressure Friction Sound Chemical Effects and Electric Current Some Natural Phenomena Light Stars and the Solar System Q1 List conditions under which combustion can take place.
There must be Fuel to burn. There must be Air to supply oxygen. There must be Heat ignition temperature to start and continue the combustion process.
With a continuous supply of heat furnished by the combustion process itself , the ignition of additional fuel will continue as long as there is enough oxygen present. Thus it is obvious that these three elements must be present and satisfactorily combined before combustion can occur and continue. Remove any one of the three sides or elements and the fire will cease to burn.
Weaken any one, and the fire will weaken. Increase any one or more of the elements, and the fire will increase in intensity. Armed with this knowledge the fire fighter or the prescribed burner can do much to manage a fire.
Do not touch it without protection. Young children should not attempt this exercise without adult supervision. There are various ways in which the fire triangle can be broken or altered. One example of how the triangle can be broken can be done with a short candle and a jar.
Light the candle and set it on a flat surface. After a short time, the candle will go out. This occurs because all of the oxygen inside the jar has been used up by the burning candle and no additional oxygen can get to the candle because of the jar.
Before you put the jar over the burning candle, you had all the ingredients necessary for combustion; heat from the match, fuel in the candle and oxygen from the air.
Relight the candle. This time, take a pair of scissors and cut off the wick below the flame and remove the candle. Again, the fire will go out after a short period when the rest of the wick that was left on the scissors is consumed. This time you had plenty of oxygen in the air but you removed the fuel. The same principle is used in fighting wildfires. Remove heat, oxygen or fuel and the fire goes out.
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