Combustion and Flame Notes PDF

COMBUSTION AND FLAME Extra notes I. Give reasons: 1. Water should not be used to put out a fire caused by oil or petrol. Ans. Water is heavier than oil and petrol. Hence if water is used to put off the fire caused due to oil or petrol, the water will sink bel...

COMBUSTION AND FLAME Extra notes I. Give reasons: 1. Water should not be used to put out a fire caused by oil or petrol. Ans. Water is heavier than oil and petrol. Hence if water is used to put off the fire caused due to oil or petrol, the water will sink below the oil. This will keep the fire burning and will not extinguish it. 2. For any fuel to burn, it is necessary to reach the ignition temperature. Ans. The ignition temperature of a substance is the minimum temperature that is required to start or cause combustion. Any combustible substance cannot catch fire as long as its temperature is lower than its ignition temperature. Once the fuel reaches its ignition temperature, the combustion reaction of the fuel becomes self- sustaining only above its ignition temperature. Hence it is necessary to reach the ignition temperature for any fuel to burn. II. Answer the following: 1. Why should we not burn coal in a closed room. Ans. Burning coal in a closed room produces carbon monoxide gas. It is a poisonous gas and has affinity for haemoglobin. This reduces the oxygen carrying capacity of the blood in the human body and can lead to suffocation and eventual death. So, it is advised not to burn coal in closed rooms. 2. Respiration is a type of combustion. Explain. Ans. The process of burning substance in presence of oxygen to generate energy is called as combustion. During the process of respiration, food undergoes oxidation in a slow and controlled manner to produce energy. Oxygen is utililzed during this process. Hence, respiration is a slow combustion process. 3. Distinguish between complete and incomplete combustion. Complete combustion Incomplete combustion 1. The combustion reaction that takes 1. The combustion reaction takes place place in the presence of a sufficient or in the presence of an insufficient abundant amount of oxygen is called a amount of oxygen. combustion reaction. 2. In this type of combustion, the flame 2. In this type of combustion, flame produced is bluish in colour. produced is of yellow colour. 3. Complete combustion does not 3. Incomplete combustion produces produce smoke smoke which contains soot particles