Deck 17: Forensic Aspects of Fire and Explosion Investigation

Question 1

Telltale signs of arson include:

A) Separate points of origin.
B) Trails of burn patterns.
C) The presence of containers.
D) All of the above

Answer 1

D

Question 2

When investigators search a fire scene,the first focus must be on:

A) Finding the origin of the fire.
B) Interviewing eyewitnesses.
C) Taking photographs and making sketches.
D) All of the above

Answer 2

A

Question 3

The minimum temperature at which a fuel will spontaneously ignite is called:

A) A dangerous place to store flammable liquids.
B) The ignition temperature.
C) The heat of combustion.
D) The flash point.

Answer 3

B

Question 4

Which of the following statements is true?

A) All chemical reactions give off heat.
B) Heat is required to change one element into another.
C) A chemical equation shows the number of atoms lost during a chemical reaction.
D) Oxidations are chemical reactions that produce new substances.

Question 5

Hydrocarbon accelerants can be detected by:

A) A portable detector (sniffer).
B) Trained dogs.
C) Most people.
D) Both A and B

Question 6

A fuel can only achieve combustion in:

A) The solid state.
B) The liquid state.
C) The gaseous state.
D) A liquid-solid phase.

Question 7

Which is a natural heat-producing process that may give rise to a fire?

A) Chain reaction
B) Flash point
C) Ignition point
D) Spontaneous combustion

Question 8

What is the decomposition of organic matter by heat?

A) Combustion
B) Pyrolysis
C) Ignition temperate
D) Radiation

Question 9

Which instrumentation is considered the most sensitive and reliable for detecting and characterizing flammable residues?

A) NAA
B) IR
C) GC
D) TLC

Question 10

The likelihood that spontaneous combustion will occur in improperly ventilated containers of highly unsaturated oils is ________ the likelihood that such combustion will occur with hydrocarbon lubricating oils.

A) Less than
B) Greater than
C) The same as

Question 11

Which of the following CANNOT be determined from a laboratory examination of evidence recovered from an arson?

A) The presence of gasoline, kerosene, or turpentine in debris
B) Origin of liquid gasolines
C) The brand name of gasoline used to start the fire
D) The ignition mechanism used by the arsonist

Question 12

What is the rapid combination of oxygen with a fuel,which produces a noticeable release of energy?

A) The flash point
B) Explosion
C) Ignition
D) Combustion

Question 13

The minimum temperature at which fuel vapor will ignite is known as:

A) The glow temperature
B) The boiling point
C) The flash point
D) The ignition temperature

Question 14

Which substance has the highest ignition temperature?

A) Turpentine
B) Fuel oil #2
C) Benzene
D) Kerosene

Question 15

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

A) Ignition temperature
B) Sublimation temperature
C) Critical temperature
D) Flash point

Question 16

Which chemical reaction is associated with a fire?

A) Reduction
B) Oxidation
C) Precipitation
D) None of the above

Question 17

Gasoline residues are best characterized by:

A) Ultraviolet analysis.
B) Infrared spectrophotometry.
C) Gas chromatography.
D) Emission spectroscopy.

Question 18

Factors that can contribute to abnormal observations at a fire scene include:

A) Winds or drafts.
B) Secondary fires due to collapsing floors or roof.
C) Stairways or elevator shafts.
D) All of the above

Question 19

What is the concentration at which a vapor-to-fuel mixture in the air is capable of burning?

A) Flammable range
B) Heat of combustion
C) Lethal range
D) Spontaneous concentration

Question 20

Arson investigators must work quickly to collect evidence at a fire scene because:

A) Accelerant residues may quickly evaporate.
B) Safety requirements may require that cleanup and salvage operations begin quickly.
C) Accelerants in soil may rapidly degrade.
D) All of the above

Question 21

Materials that have electrons firmly attached to their molecules:

A) Transfer heat by convection
B) Transfer heat by radiation
C) Are excellent conductors of heat
D) Are poor conductors of heat

Question 22

What is radiation?

A) Movement of heat through a solid object
B) Transfer of heat energy from a heated surface to a cooler surface
C) Transfer of heat energy by movement of molecules within a liquid or gas
D) None of the above

Question 23

Which is the most widely used low explosive?

A) Potassium chlorate and sugar
B) Black powder
C) Smokeless powder
D) Both B and C

Question 24

Water being heated on a stove illustrates the concept of:

A) Conduction.
B) Radiation.
C) Convection.
D) All of the above

Question 25

Which is a chemical used to synthesize the explosive TATP?

A) Aluminum
B) Magnesium
C) Hydrogen peroxide
D) Potassium chlorate

Question 26

Most explosives can be recovered from debris for future study by being rinsed with:

A) Water.
B) Toluene.
C) Kerosene.
D) Acetone.

Question 27

Which is NOT a high explosive?

A) Black powder
B) Dynamite
C) RDX
D) TNT

Question 28

Heat energy can ignite distant objects through the transmission of:

A) Electrons
B) Streamers
C) Electromagnetic energy
D) Oxidizing agents

Question 29

Which is an explosive readily detonated by heat or shock?

A) Dynamite
B) Secondary explosive
C) Primary explosive
D) ANFO

Question 30

The quantity of heat from a chemical reaction comes from:

A) The breaking and formation of chemical bonds
B) The presence of oxygen in the reaction
C) The emission of radiation
D) The composition of the fuel-air mix

Question 31

Combustion occurring at the surface of a solid describes:

A) Pyrolysis
B) Spontaneous combustion
C) Flash point
D) Glowing combustion

Question 32

What is the major advantage of using the vapor concentration technique with gas chromatography?

A) Low resolution of peaks associated with volatile residues
B) Ability to determine relative concentration of solid residues
C) Only non-volatile residues will be detected
D) High sensitivity for detecting volatile residues

Question 33

Movement of heat through a solid object is caused by:

A) Conduction
B) Radiation
C) Convection
D) Both A and C

Question 34

Which is a homemade explosive that has been used by terrorist organizations in the Middle East?

A) PETN
B) TNT
C) TATP
D) RDX

Question 35

What is NOT true about primary explosives?

A) They will detonate violently.
B) Lead azide and lead styphnate are examples.
C) They are used in blasting caps.
D) They are very stable.

Question 36

Complex chromatographic accelerant patterns can be simplified by:

A) Gas chromatography
B) Thin-layer chromatography
C) Mass spectrometry
D) Headspace analysis

Question 37

Which of the following is a poor conductor of heat?

A) Wood
B) Plastic
C) Paper
D) All of the above

Question 38

All combustible fuels simultaneously igniting to engulf a structure in flames is known as:

A) Pyrolysis
B) Spontaneous combustion
C) Combustion
D) Flashover

Question 39

A common classification system characterizes ignitable liquids based on their boiling point ranges and number of ________ molecules as light,medium,and heavy petroleum distillates.

A) Carbon
B) Hydrogen
C) Petroleum
D) Petrol

Question 40

The transfer of heat energy by the movement of molecules within a liquid or gas is:

A) Radiation
B) Oxidation
C) Convection
D) Conduction

Question 41

The speed in a low explosive is called the speed of:

A) Detonation.
B) Deflagration.
C) Oxidation.
D) Combustion.

Question 42

Single-base smokeless powder consists of:

A) Nitrocellulose and nitroglycerine.
B) Potassium chlorate and nitrocellulose.
C) Nitrocellulose.
D) Nitroglycerine.

Question 43

Rusting is not accompanied by combustion.

Question 44

Which of the following statements is FALSE?

A) Potassium chlorate can be mixed with sulfuric acid and sugar to create a low explosive.
B) Chemicals that supply oxygen are known as oxidizing agents.
C) Smokeless powder is a low explosive.
D) Dynamite is an initiating high explosive.

Question 45

A procedure commonly used as a screening test for explosive residues is:

A) Color spot tests.
B) Thin-layer chromatography.
C) Gas-chromatography-mass spectrometry.
D) All of the above

Question 46

Explosives that decompose at relatively slow rates are classified as:

A) Decomposing explosives.
B) Low explosives.
C) High explosives.
D) Slow explosives.

Question 47

Which are common chemical ingredients of black powder?

A) Aluminum, potassium, nitrate, nitrocellulose
B) Sulfur, carbon, nitrogen
C) Carbon, nitrocellulose, potassium chlorate
D) Potassium nitrate, charcoal, sulfur

Question 48

A low explosive has a velocity of detonation less than:

A) 150 meters per second.
B) 500 meters per second.
C) 1000 meters per second.
D) 1500 meters per second.

Question 49

High explosives can be classified as either ________ or ________ explosives.

A) Civilian; military
B) Initial; secondary
C) Military grade; non-military grade
D) Primary; secondary

Question 50

Which type(s)of screening and confirmation tests are used for analyzing evidence of explosives?

A) TLC
B) Color spot tests
C) Gas chromatography/mass spectrometry
D) All of the above

Question 51

Which is an initiating explosive often used in detonators?

A) Lead azide
B) PETN
C) TNT
D) Dynamite

Question 52

Which is often used as the explosive core in a detonating cord?

A) TNT
B) PETN
C) RDX
D) C-4

Question 53

Which type of explosives detonate almost instantaneously to produce a smashing or shattering effect?

A) Dentoating explosives
B) Low explosives
C) High explosives
D) Instantaneous explosives

Question 54

Which is a device used to screen objects for the presence of explosive residues?

A) X-ray diffraction
B) Mass spectrometry
C) Infrared spectrophotometry
D) Ion mobility spectrometry

Question 55

Molecules must absorb energy when their bonds are reformed and they liberate energy when their bonds break apart.

Question 56

Which is available in commercial form as fertilizer?

A) Ammonium nitrate
B) Triacetone triperoxide
C) Diazodinitrophenol
D) Potassium chlorate

Question 57

The quantity of heat from a chemical reaction comes from the presence of oxygen in the reaction.

Question 58

Examples of secondary explosives do NOT include:

A) TNT
B) PETN
C) RDX
D) Lead azide

Question 59

Which of the following is NOT a military explosive?

A) RDX
B) C-4
C) TNT
D) Nitroglycerin

Question 60

Many explosives must have their own source of:

A) Fuel.
B) Oxygen.
C) Heat.
D) Energy.

Question 61

Two to three quarts of ash and soot debris must be collected at the point of origin of a fire when arson is suspected.

Question 62

If the fuel concentration in the fuel-air mix is too low or too great,combustion does not occur.

Question 63

The only ingredients required for a low explosive are fuel and a good oxidizing agent.

Question 64

A fuel must be in its gaseous state to produce combustion when it reacts with oxygen.

Question 65

The phenomenon of flashover is an example of radiation.

Question 66

Water does not interfere with laboratory methods used to detect and characterize flammable liquid residues.

Question 67

A fuel does not need to be present to initiate and sustain combustion.

Question 68

Paper is not good for spreading a fire and causing ignitions far from the initial heat source.

Question 69

Detonation is characterized by very rapid oxidation that produces heat,light,and a subsonic pressure wave.

Question 70

The most common igniter is an electrical sparking device.

Question 71

A burning cigarette is an example of spontaneous combustion.

Question 72

The easiest way to recover accelerant residues from fire-scene debris is to heat the airtight container in which the sample is sent to the laboratory.

Question 73

A search of the fire scene must focus on finding the fire's point of origin.

Question 74

Arson investigators must work quickly to collect evidence at a fire scene because any accelerant residues may evaporate within a few days or even hours.

Question 75

A fire will burn until either the oxygen or the fuel is exhausted.

Question 76

Combustion is accompanied by the production of noticeable heat and light.

Question 77

Wood is a poor insulator.

Question 78

The brand name of a gasoline sample cannot currently be determined by any technique.

Question 79

Heat energy is liberated in an endothermic reaction and absorbed in an exothermic reaction.

Question 80

Low explosives detonate relatively slowly (less than 1,000 meters per second),while high explosives detonate very rapidly (from 1,000 to 8,500 meters per second).