Deck 13: Trace Evidence I: Hairs and Fibers

Question 1

A natural heat-producing process that may give rise to a fire is:

A) a chain reaction.
B) spontaneous combustion.
C) flash point.
D) ignition point.
E) glowing combustion.

Answer 1

B

Question 2

Which substance has the highest ignition temperature?

A) kerosene
B) benzene
C) fuel oil #2
D) turpentine
E) octane

Answer 2

B

Question 3

A fuel can only achieve combustion in:

A) the solid state.
B) in a liquid-solid phase.
C) the liquid state.
D) the gaseous state.
E) none of the above

Answer 3

D

Question 4

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

A) a dangerous place to store flammable liquids.
B) the flash point.
C) the heat of combustion.
D) the boiling point.
E) the ignition temperature.

Question 5

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

A) accelerants in soil may rapidly degrade.
B) accelerant residues may quickly evaporate.
C) safety requirements may require that cleanup and salvage operations begin quickly.
D) untrained personnel may contaminate the scene.
E) all of the above

Question 6

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

A) sublimation temperature.
B) flash point.
C) flammable range.
D) ignition temperature.
E) critical temperature.

Question 7

Heat energy can ignite distant objects through the transmission of:

A) electrons.
B) electromagnetic energy.
C) streamers.
D) oxidizing agents.
E) none of the above

Question 8

The concentrations at which a vapor-to-fuel mixture in the air is capable of burning is referred to as the:

A) ignition value.
B) flammable range.
C) heat of combustion.
D) lethal range.
E) spontaneous concentration.

Question 9

The decomposition of organic matter by heat describes:

A) convection.
B) radiation.
C) ignition temperate.
D) pyrolysis.
E) combustion.

Question 10

Hydrocarbon accelerants can be detected by:

A) a portable detector (sniffer).
B) trained dogs.
C) most people.
D) both A and B
E) both B and C

Question 11

Materials that have electrons firmly attached to their molecules

A) transfer heat by radiation.
B) are usually metals.
C) are poor conductors of heat.
D) are excellent conductors of heat.
E) transfer heat by convection.

Question 12

The movement of heat through a solid object is a process known as:

A) convection.
B) radiation.
C) pyrolysis.
D) oxidation.
E) conduction.

Question 13

Telltale signs of arson include:

A) separate points of origin.
B) "streamers" connecting burned areas.
C) the presence of accelerant containers.
D) trails of burn patterns.
E) all of the above

Question 14

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

A) stairways or elevator shafts.
B) winds or drafts.
C) secondary fires due to collapsing floors or roof.
D) holes in the structure.
E) all of the above

Question 15

The rapid combination of oxygen with a fuel, which produces a noticeable release of energy, is called:

A) ignition.
B) liberation.
C) combustion.
D) explosion.
E) the flash point.

Question 16

The chemical reaction associated with a fire is:

A) reduction.
B) acid-base.
C) precipitation.
D) oxidation.
E) none of the above

Question 17

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

A) finding the origin of the fire.
B) taking photographs and making sketches.
C) looking for signs of breaking and entering.
D) interviewing eyewitnesses.
E) all of the above

Question 18

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

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

Question 19

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) greater than
B) the same as
C) less than

Question 20

Gasoline residues are best characterized by:

A) emission spectroscopy.
B) ultraviolet analysis.
C) infrared spectrophotometry.
D) gas chromatography.
E) atomic absorption.

Question 21

List and explain the telltale signs that a fire has been accelerant initiated.

Question 22

Combustion occurring at the surface of a solid describes:

A) pyrolysis.
B) flash point.
C) glowing combustion.
D) spontaneous combustion.
E) convection.

Question 23

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

A) only non-volatile residues will be detected
B) long analysis time allows for full separation of components
C) high sensitivity for detecting volatile residues
D) ability to determine relative concentration of solid residues
E) low resolution of peaks associated with volatile residues

Question 24

List the conditions that are necessary to initiate and sustain combustion.

Question 25

Describe the three mechanisms of heat transfer.

Question 26

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

A) oxidation.
B) conduction.
C) pyrolysis.
D) radiation.
E) convection.

Question 27

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

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

Question 28

Complex chromatographic patterns can be simplified by passing the components emerging from the gas chromatographic column through a(n):

A) TLC
B) SEM-EDX
C) capillary column
D) infrared microspectrophotometer
E) mass spectrometer

Question 29

Describe how an investigator would collect and preserve evidence at a scene of a suspected arson fire.

Question 30

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

A) flashover.
B) pyrolysis.
C) combustion.
D) flash point.
E) spontaneous combustion.

Question 31

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) Petroleum
B) Hydrogen
C) Oxygen
D) Petrol
E) Carbon

Question 32

Complex chromatographic accelerant patterns can be simplified by:

A) headspace analysis.
B) thin-layer chromatography.
C) mass spectrometry.
D) gas chromatography.
E) a portable hydrocarbon detector.

Question 33

Explain how a forensic laboratory technician would test for the presence and identification of hydrocarbon residues.