Ch. 10 Arson

Question 1

accelerant

Answer 1

any material that is used to start a fire, but usually an ignitable liquid

Question 2

activation energy

Answer 2

the amount of energy that must be applied to reactants to overcome the energy barrier to their reaction

Question 3

alkane

Answer 3

a hydrocarbon containing only carbon-carbon single bonds

Question 4

backdrift

Answer 4

an event in which an oxygen-starved fire suddenly receives oxygen

• sudden rush of oxygen causes the smoldering materials present to reignite at the same time
• causes an explosion

Question 5

combustible liquids

Answer 5

liquids w/ flash points ≥ 100˚F (38˚C)

(ie) kerosene & fuel oil

Question 6

endothermic reaction

Answer 6

a chemical reaction in which heat is absorbed

Question 7

energy

Answer 7

the ability to do work

- forms: heat, chemical, electrical, or mechanical

Question 8

exothermic reaction

Answer 8

a chemical process that releases heat to the surroudnings

Question 9

flammable liquids

Answer 9

liquids w/ flash points ≤ 100˚F (38˚C)

Question 10

flammable range

Answer 10

the range of vapor concentrations in air that is capable of burning

Question 11

flashover

Answer 11

the temperature at which a fire begins unrestrained growth

- can cause complete destruction

Question 12

flash point

Answer 12

the minimum temperature at which a liquid fuel will produce enough vapor to burn

Question 13

fractional distillation

Answer 13

the separation of components of petroleum by boiling followed by condensation into fractions w/ similar boiling ranges

• small molecules w/ low bp emerge 1st
• large molecules w/ high bp emerge 2nd

Question 14

gas chromatography (GC)

Answer 14

a technology used to separate complex mixtures of hydrocarbons, alcohols, ethers & ketones

Question 15

gas chromatography-mass spectrometry (GC-MS)

Answer 15

use of a gas chromatograph (separates components of a mixture) in conjunction w/ a mass spectrometer (identifies each component by measuring its mass)

Question 16

headspace

Answer 16

the space above fire debris that has been stored in a sealed container

Question 17

hydrocarbon

Answer 17

a chemical that contains only two elements: carbon & hydrogen

Question 18

incipient stage

Answer 18

the growth phase of a fire, which begins at ignition

Question 19

kerosene

Answer 19

a petroleum fraction that boils at temperatures btwn 100˚F (149˚C) and 550˚F (288˚C)
- used in space heaters, cook stoves & wick lamps

Question 20

lower explosive limit (LEL)

Answer 20

the lowest concentration of vapor in air that will burn

Question 21

oxidation

Answer 21

a chemical reaction in which oxygen is combined w/ other substances

Question 22

pyrolysis

Answer 22

the decomposition of a substance by application of heat

Question 23

structural isomers

Answer 23

organic compounds that have the same formula but different molecular structures

Question 24

upper explosive limit (UEL)

Answer 24

the highest concentration of vapor in air that will burn

Question 25

_________ is the leading cause of arson.

Answer 25

drugs

Question 26

Oxidation is a chemical reaction between a substance and _________.

Answer 26

oxygen

Question 27

_______ reactions produce heat.

Answer 27

exothermic

Question 28

_______ reactions absorb heat.

Answer 28

endothermic

Question 29

The rate of chemical reaction is the ________ at which reactions are converted into products.

Answer 29

energy

Question 30

The minimum amount of energy that a reactant molecule must possess to react is called the ________.

Answer 30

activation energy

Question 31

The three factors that affect the rate of a chemical reaction are _________, ________, and _________.

Answer 31

1) temperature 2) concentration of reactants 3) presence of catalysts

Question 32

A fuel will produce a flame only when a sufficient number of fuel molecules are in the ________ state.

Answer 32

gaseous

Question 33

The _______ is the minimum temperature at which a liquid fuel will produce enough vapor to burn.

Answer 33

flash point

Question 34

Liquids with flash points of 100˚F (38˚C) or higher are known as _______ liquids.

Answer 34

combustible

Question 35

Liquids with flash points of 100˚F (38˚C) or lower are known as _______ liquids.

Answer 35

flammable

Question 36

The breakdown of solids by heat is called ________.

Answer 36

pyrolysis

Question 37

Yellow flames indicate ________ combustion.

Answer 37

incomplete

Question 38

________ is a term that describes combustion at a surface that occurs without flames.

Answer 38

combustion

Question 39

The concentration of gaseous fuel that will support combustion is called the _________.

Answer 39

flammable range

Question 40

The lowest concentration of gaseous fuel that will support combustion is called the _______.

Answer 40

lower explosive limit (LEL)

Question 41

A vapor density that is ________ (greater/less) than 1 means the vapor is lighter than air.

Answer 41

less

Question 42

The rate of chemical oxidation (burning) ______ for every 50˚F (10˚C) rise in the temperature.

Answer 42

doubles

Question 43

The first stage of a fire is called the ________ stage.

Answer 43

incipient

Question 44

The second stage of a fire is called the ________ stage.

Answer 44

growth

Question 45

______ occurs when there is spontaneous combustion of all fuels in a room.

Answer 45

flashover

Question 46

If oxygen suddenly comes in contact with smoldering material, an explosive reaction can take place that is commonly called ________.

Answer 46

backdrift

Question 47

Heating wood causes it to decompose by releasing gases and leaving a solid residue called _________.

Answer 47

ash

Question 48

A common fire pattern has a distinctive ______ shape.

Answer 48

V

Question 49

In determining the origin of a fire, the _______ theory helps identify the source of the fire.

Answer 49

backwards

Question 50

Hydrocarbons that contain only single bonds are called ________.

Answer 50

alkanes

Question 51

Crude petroleum is separated by _______ ________ in the refinery.

Answer 51

fractional distillation

Question 52

Accelerant residue in fire debris is removed by one of two techniques ________ or ______.

Answer 52

passive headspace diffusion (charcoal sampling) | solid-phase microextraction

Question 53

In gas chromatography, the sample is usually introduced into the GC instrument by a(n) _________.

Answer 53

injector

Question 54

Generally, the component of the sample with the _______ boiling point comes out last.

Answer 54

highest

Question 55

Individual components of a sample produce symmetrically shaped GC peaks, and the ________ is proportional to the concentration of that component.

Answer 55

area under each peak

Question 56

Each component of a sample has a unique GC _______ ________.

Answer 56

fingerprint