Combustion and Flame (Class VIII)
| Description: Combustion and Flame | |
| Number of Questions: 17 | |
| Created by: Vaibhav Pathak | |
| Tags: Combustion and Flame Stem and Its Functions Leaf and Its Structure Classification of Plants into Herbs, Shrubs and Trees Combustion, Types of Combustion Flame, Structure of a Flame |
Which of the following is the ignition temperature of phosphorus?
During respiration, the digested food is broken down by the reaction with oxygen in the body cells to produce _______, water and heat energy.
The electrical fires or fires caused due to burning of oil or petrol are extinguished by using _________ fire extinguisher.
Which of the following chemicals is/are poisonous and no longer used in making the tips of matchsticks these days?
a. White phosphorus b. Antimony trisulphide c. Potassium chlorate
Which of the following materials do(es) not support combustion?
a. Nitrogen b. Oxygen c. Noble gases
Match the following ||| |---|---| |a. When a combustible material burns at a slow or moderate rate, it is called|1. spontaneous combustion| |b. When a combustible material burns quickly to produce heat and light, it is called|2. slow combustion| |c. When a combustible material suddenly bursts into flames, without the application of apparent cause, it is called|3. rapid combustion|
Which of the following fuels has the greatest calorific value?
Which of the following statements is/are false?
a. Spontaneous combustion never takes place at the room temperature. b. The heat required for spontaneous combustion is produced inside the substance by its slow oxidation. c. A large amount of gas is released quickly in an explosive combustion.
Which of the following is an example of spontaneous combustion?
Which of the following statements is/are false?
a. The materials that produce light energy on burning in air are called fuels. b. When magnesium is heated in air, it catches fire and burns with a dazzling white flame. c. On heating, charcoal burns to produce a large amount of heat and a dull red light.
Which of the following methods cannot be used to extinguish fire?
a. By removing the combustibe substances b. By removing the heat c. By increasing the supply of air to the burning substances
Which of the following is not a characteristic of an ideal fuel?
If the oxygen supply is sufficient, then the fuel burns completely, producing mainly a blue flame. In which of the following cases is a blue flame produced?
a. The burning of LPG in a kitchen gas stove b. The burning of kerosene in a lamp c. The burning of a wax candle
The substances that do not undergo combustion are called non-combustible substances. Which of the following is a non-combustible substance?
Which of the following substances does not burn by producing a flame?
A few chemicals release carbon dioxide gas, by getting decomposed in the heat of the fire, for extinguishing a fire. Which of the following chemicals cannot be used for this purpose?
a. Baking soda b. Potassium bicarbonate c. Citric acid
Match the following:
| Zones of a flame | Features |
| a. The innermost zone | 1. Blue in colour and the hottest |
| b. The middle zone | 2. Yellow in colour and moderately hot |
| c. The outer zone | 3. Black in colour and the coldest |