🔥 1B — Fire Triangle/Tetrahedron & Combustion

Can energy change from one form to another?

Yes, energy can be converted from one form to another.

What happens to chemical energy during combustion?

The potential chemical energy of the fuel is converted primarily into heat and sometimes light.

What is a joule?

The SI unit used to measure energy.

What is a British thermal unit (Btu)?

The amount of heat required to raise the temperature of 1 pound of water by 1°F.

What is the relationship between joules and Btu?

1 Btu equals approximately 1,055 joules.

What is an exothermic reaction?

A reaction that emits energy as it occurs.

What type of reaction is fire?

Fire is an exothermic chemical reaction that releases energy as heat and sometimes light.

What is an endothermic reaction?

A reaction that absorbs energy as it occurs.

What is an example of an endothermic process?

Converting liquid water into steam because energy must be added.

What is the fire triangle?

A model showing the three elements necessary for combustion: fuel, oxygen, and heat.

What happens when one element of the fire triangle is removed?

The fire is extinguished.

What is the fire tetrahedron?

A model that includes fuel, oxygen, heat, and an uninhibited chemical chain reaction.

What additional element does the fire tetrahedron contain that the fire triangle does not?

The chemical chain reaction.

What must be present for flaming combustion to occur?

Fuel, oxygen, heat, and an uninhibited chemical chain reaction in the proper proportions and physical proximity.

What state must fuels be in to burn in flaming combustion?

Gaseous state.

What must solid and liquid fuels do before they can ignite?

They must be converted to gases or vapors.

What is pyrolysis?

The chemical change that occurs when solid fuel is heated and produces fuel gases.

What is vaporization?

The physical change in which a liquid changes into a vapor or gas.