1.
How does combustion take place?
Correct Answer
B. Oxygen reacts with another substance
Explanation
Combustion is a chemical reaction that occurs when a substance reacts with oxygen. In this process, the substance undergoes rapid oxidation, releasing heat and light energy. The given answer correctly states that combustion takes place when oxygen reacts with another substance. This reaction typically involves the elements carbon, hydrogen, and oxygen, which are commonly found in fuels like wood, gasoline, and natural gas. The oxygen acts as an oxidizing agent, breaking the chemical bonds in the fuel molecules and producing carbon dioxide, water, and other combustion byproducts.
2.
What does incomplete combustion produce?
Correct Answer
A. Carbon monoxide
Explanation
Incomplete combustion occurs when there is insufficient oxygen for a fuel to burn completely. In this case, carbon monoxide is produced as a byproduct. Carbon monoxide is a colorless, odorless, and highly toxic gas. It is formed when carbon-based fuels, such as coal, oil, or gas, are burned without enough oxygen. This is why it is important to ensure proper ventilation and complete combustion to avoid the dangerous buildup of carbon monoxide in enclosed spaces.
3.
What is required to make a flame?
Correct Answer
C. Oxygen
Explanation
To make a flame, oxygen is required. Oxygen is a crucial component in the process of combustion. It supports the chemical reaction that occurs between a fuel source and heat, allowing the fuel to burn and produce a flame. Without oxygen, the fuel cannot undergo combustion and a flame cannot be formed.
4.
What does combustion in general produce?
Correct Answer
C. Heat and light
Explanation
Combustion in general produces heat and light. When a substance undergoes combustion, it reacts with oxygen in the air to release energy in the form of heat and light. This process is commonly observed in the burning of fuels, such as wood or gasoline. The heat produced during combustion is a result of the chemical reaction, while the light is emitted as a byproduct of the high temperatures reached during the process.
5.
Incomplete combustion only happens when there is not enough ____ to react
Correct Answer
oxygen
Explanation
Incomplete combustion occurs when there is insufficient oxygen available for a substance to react completely. In this case, the question is asking for the missing element that is required for complete combustion, and the correct answer is oxygen.
6.
Complete combustion produces ____
Correct Answer
carbon dioxide
Explanation
Complete combustion occurs when a fuel combines with oxygen in the presence of a sufficient amount of heat. In this process, the fuel is completely oxidized, resulting in the production of carbon dioxide as the only product. This means that all the carbon in the fuel is converted into carbon dioxide. Therefore, the correct answer is carbon dioxide.
7.
Combustion is an endothermic reaction
Correct Answer
B. False
Explanation
Combustion is an exothermic reaction, not an endothermic reaction. In combustion, a substance reacts with oxygen to produce heat and light. This process releases energy in the form of heat, making it an exothermic reaction. Endothermic reactions, on the other hand, absorb heat from their surroundings.