Basic Firefighter Written Practice Exam

To achieve flaming combustion, solid or liquid fuels must be converted to which phase?

1. Solid

2. Liquid

3. Gas

4. Plasma

The correct answer is: Gas

To achieve flaming combustion, solid or liquid fuels must be converted to the gas phase. This is because combustion is a chemical reaction that requires the reactants to be in a state where they can efficiently mix with oxygen in the air. When solid fuels, such as wood, are heated, they undergo a process called pyrolysis, where they break down into gas, vapor, and char. For liquid fuels, the process involves evaporation where the heat converts the liquid into gas. Once in the gas phase, these fuel vapors can then react with oxygen at the flame front, which is necessary for the flaming combustion to occur. While solid and liquid phases are important for the initial fuel source, they must eventually be converted to gas to sustain the combustion reaction that produces flames. Plasma, a state of matter where gas is energized to the point that electrons are disbanded from their parent atoms, is not typically involved in standard flaming combustion processes involving common fuels.