Exam 4

Air is a mixture of _____% oxygen and _____% nitrogen, with 1% of other elements remaining.

21; 78

What source of heat or form of energy is based on the breaking down and recombination of molecules?

Chemical

What fire classification refers to combustible metals?

Class D

Scientific theory and experiments show that there is no limit below which matter can be cooled.

False

What is the term for the minimum temperature of a liquid at which it gives off vapors sufficient to form an ignitable mixture with air, but ignition is not sustained?

Flash point

_____ is described as anything that will burn.

Fuel

Which of the following fuels always fills the container in which it is stored?

Gas

Which of the following statements is true?

Gas molecules vibrate faster than solid molecules.

During what fire stage does convected heat rise and preheat fuels above the fire?

Growth

What is the main element in organic fuels?

Hydrocarbon

What is the term for the ability of a substance to mix with water?

Miscibility

Which of the following is not a by-product of incomplete combustion?

Oxygen

What is the chemical decomposition of matter through the action of heat?

Pyrolysis

Which of the following terms refers to the transfer of heat by wavelengths of energy?

Radiation

All molecules vibrate at normal temperatures.

True

A vapor that is ______ its upper flammable limit is said to be too rich to burn.

above

The point at which vapor pressure equals atmospheric pressure at the surface of the liquid is called _____ .

boiling point

The four components of a fire tetrahedron are fuel, air, heat, and ____ .

chemical chain reaction

Solids, liquids, and gases are the three states of _____ .

matter

The weight of a liquid as compared to the weight of an equal volume of water is called ____ .

specific gravity

Fire is based on three elements known as the fire triangle.

true

Fire is the rapid, self-sustaining oxidation process accompanied by the evolution of heat and light in varying intensities.

true

Most common fires involve a fuel composed of mostly carbon and hydrogen in an atmosphere with oxygen present.

true

The relative density of a vapor or gas as compared to air is the _____.

vapor density

The ease with which a fuel gives off vapors at ambient temperature is called _____ .

volatility