Final answer:
True, most common fires involve combustion of hydrocarbon fuels containing carbon and hydrogen, in the presence of oxygen, producing carbon dioxide, water, and heat.
Step-by-step explanation:
The statement that most common fires involve a fuel composed of mostly carbon and hydrogen in an atmosphere with oxygen present is true. This describes the typical combustion reaction involving hydrocarbons, such as methane (CH4), propane, and natural gas. In an adequate supply of oxygen, these compounds combust to form carbon dioxide (CO2), water (H2O), and heat. For example, the combustion of methane is represented by the chemical equation CH4 + 2O2 → CO2 + 2H2O + Heat. This process is the basis for cooking, heating, and many other applications that require energy.
The most common fuels, such as natural gas, coal, and oil, consist largely of hydrocarbons and are the predominant sources of energy through combustion. However, when there is a limited oxygen supply, incomplete combustion may occur, producing carbon monoxide (CO) and potentially leading to dangerous situations.