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Flashcards in Chapter 5 Deck (57)
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1

What is a chemical process of oxidation that occurs at a rate fast enough to produce heat and usually light i the form of either a glow or a flame?

Combustion

2

What is a rapid oxidation process which is a chemical reaction resulting in the evolution of light and heat in varying intensities?

Fire

3

What is a form of energy characterized by the vibration of molecules and is capable of initiating and supporting chemical changes and changes in state?

Heat

4

What is the measure of a materials ability to transfer heat energy to other objects?

Temperature

5

What is a material that will main combustion under specified environmental conditions?

Fuel

6

What is any material that readily yields oxygen or other oxidizing gas, or that readily reacts to promote or initiate combustion of combustible material?

Oxidizer

7

What is potential energy?

stored energy possessed by an object that can be released in the future to perform work once released

8

What is kinetic energy?

the energy possessed by a body because of its motion

9

What is defined in terms of mechanical energy? It is equal to the energy expanded in applying a force of one newton through a distance of one meter.

Joules

10

What is an exothermic reaction?

chemical reaction that releases thermal energy or heat

11

What is an endothermic reaction?

chemical reaction that absorbs thermal energy or heat

12

What is pyrolysis?

the chemical decomposition of a solid material by heating. Pyrolysis often precedes combustion

13

What is the physical process that changes a liquid into a gaseous state?

Vaporization

14

What is ignition?

the process of initiation self-sustained combustion

15

What are the two forms of ignition?

piloted ignition and autoignition (non piloted)

16

What is the moment when a mixture of fuel and oxygen encounters an external heat source with sufficient heat or thermal energy to start the combustion reaction?

Piloted ignition

17

What is the initiation of combustion by heat but without a spark or flame

autoignition

18

What is the autoignition temperature?

the minimum temperature to which a fuel in the air must be heated in order to start self-sustained combustion. The autoignition temperature of a substance is always higher than its piloted ignition temperature

19

What is a visible, luminous body of a burning gas emitting radiant energy including light of various colors given off by burning gases or vapors during the combustion process?

Flame

20

What is the fire triangle?

a model used to explain the three elements necessary for combustion (heat fuel and oxygen)

21

What is the fire tetrahedron?

model of four elements required for a fire. the four sides represent fuel, heat, oxygen, and self-sustaining chemical chain reaction

22

What are materials that absorb heat but do not participate actively in the combustion process/

Passive agent

23

What causes the most fire deaths?

toxic smoke

24

What is a colorless, odorless, dangerous (both toxic and flammable) gas formed by the incomplete combustion of carbon? It combines with hemoglobin more than 200 times fast than oxygen does

Carbon monoxide

25

What is a colorless toxic and flammable liquid until it reaches 79 degrees F? Above that temperature it becomes a gas with a faint odor similar to bitter almonds

hydrogen cyanide

26

What is a colorless odorless heavier than air gas that neither supports combustion nor burns? This is used in portable fire extinguishers as an extinguishing agent to extinguish class B or C fires by smothering or displacing oxygen.

carbon dioxide

27

What is the kinetic energy associated with the random motions of the molecules of a material or object? This is often used interchangeable with the terms heat and heat energy

Thermal energy

28

What is the measurement of heat?

Temperature

29

What form of oxidation is a chemical reaction that increases the temperature of a material without the addition of external heat?

Self-heating

30

What is the initiation of combustion of a material by an internal chemical or biological reaction that has produced sufficient heat to ignite the material?

Spontaneous ignition

31

What is the measure of the rate of heat transfer to a surface, expressed in kilowatts?

Heat flux

32

What is the transfer of heat through or between solids that are in direct contact?

Conduction

33

What is heat transfer by circulate within a medium such as a gas or a liquid?

Convection

34

What is heat transfer by way of electromagnetic energy?

Radiation

35

What are the three mechanisms in which heat can by transferred from one body to another?

conduction, convection, and radiation

36

What is the tendency or capacity to remain afloat in a liquid or rise in air or gas?

Buoyant

37

What is the upper layer of hot smoke?

a buoyant later of hot gases and smoke produced by a fire in a compartment

38

What is the fuel that is being oxidized or burned during combustion?

reducing agent

39

What is heat of combustion?

total amount of thermal energy that could be generated by the combustion reaction if a fuel were completely burned

40

What is the Heat Release Rate (HRR)

total amount of heat released per unit time

41

What is a unit of measure of power or rate or work equal to one joule per second?

Watt

42

What is the common term used to describe the gaseous state of a fuel that would normally exist as a liquid or solid at standard temperature and pressure?

Vapor

43

What is the rate at which energy is being transferred over time?

Power

44

What describes the density of gases in relation to air?

Vapor density

45

What is the vapor density of air?

1

46

What is the ratio of the mass of a given volume of liquid compared with the mass of an equal volume of water at the same temperature?

Specific gravity

47

What is the specific gravity of water?

1

48

What will flammable liquids do on waters surface? Why?

Float bc the specific gravity is less than one

49

What is the pressure that vapor's escaping from a liquid exert?

vapor pressure

50

What is the measure of the tendency of a substance to evaporate?

vapor pressure

51

What is the minimum temperature at which a liquid gives off enough vapor's to form an ignitable mixture with air near the liquids surface?

flash point

52

What is the temperature at which sufficient vapor's are being generated to sustain the combustion reaction?

Fire point

53

What does miscible mean?

materials that are capable of being mixed in all proportions

54

What are hydrocarbon fuels?

petroleum-based organic compounds that contain only hydrogen and carbon (ex. gasoline, diesel, and fuel oil)

55

What are polar solvents?

flammable liquids that have an attraction for water (ex. alcohol, ketone, methanol, ethanol)

56

What is the flammable (explosive) range?

the range between the upper flammable limit and lower flammable limit in which a substance can be ignited

57

What are free radicals?

molecular fragments that highly reactive