Question

Which of the following substances must be present in the products of a combustion reaction?

Answer 1

In combustion reactions, oxygen is required with carbon and hydrogen-containing substances to produce carbon dioxide and water as products, along with the release of heat.

Step-by-step explanation:

In a combustion reaction, specific substances must be present in the products. Oxygen is a necessary reactant for combustion to occur. The combustion process typically involves the reaction of a substance containing carbon and hydrogen with oxygen, resulting in the formation of carbon dioxide (CO2) and water (H2O), along with the release of energy in the form of heat and sometimes light. For instance, when methane (CH4) combusts, the reaction with oxygen yields carbon dioxide, water vapor, and heat as represented by the equation:

CH4 + 2O2 → CO2 + 2H2O + Heat

Under ideal conditions with ample oxygen, these are the only products. However, in non-ideal situations with limited oxygen supply, incomplete combustion can occur, potentially producing carbon monoxide (CO) and other unwanted by-products.

Answer 2

For a complete combustion reaction to occur, the essential components are the fuel, oxygen (O2), and a source of heat or ignition. The primary products of a complete combustion reaction are carbon dioxide (CO2) and water (H2O), although other byproducts may also be present depending on the specific conditions and fuel composition.

In a complete combustion reaction, several substances must be present in the products to satisfy the reaction's chemical equation. A complete combustion reaction typically occurs when a fuel combines with oxygen (O2) to produce carbon dioxide (CO2) and water (H2O) as the primary products. Here's a step-by-step breakdown:

1. Fuel: The starting point of a combustion reaction is the fuel. This is the substance that will react with oxygen to release energy. Common examples of fuels include hydrocarbons like methane (CH4), gasoline, and natural gas.

2. Oxygen (O2): Oxygen is a crucial reactant in combustion reactions. It combines with the fuel to facilitate the combustion process. In most cases, atmospheric oxygen is used, which is approximately 21% oxygen by volume.

3. Heat or Ignition Source: Combustion reactions require an initial source of heat or ignition to start the reaction. This heat energy breaks the initial chemical bonds in the fuel, allowing it to react with oxygen. Common ignition sources include sparks, flames, or other forms of heat.

4. Carbon Dioxide (CO2): The primary product of the combustion of hydrocarbons or carbon-containing fuels is carbon dioxide (CO2). This is the result of the carbon in the fuel combining with oxygen from the air.

5. Water (H2O): Another significant product of complete combustion is water (H2O). This is formed when the hydrogen in the fuel combines with oxygen from the air.

6.Other Products: Depending on the specific fuel and combustion conditions, there may be other products present in smaller quantities. These can include nitrogen oxides (NOx), sulfur dioxide (SO2), and particulate matter. The formation of these byproducts depends on the composition of the fuel and the combustion process.

It's important to note that a combustion reaction can be incomplete under certain conditions, such as insufficient oxygen or incomplete combustion of the fuel. In such cases, carbon monoxide (CO) and other incomplete combustion products may be present in the products.