CHS EXAM 3 QUESTIONS WITH
COMPLETE SOLUTIONS27
Rhodizonate Test - ANSWERS-Test for lead residue around bullet hole
Positive test results in a scarlet color. - ANSWERS-Changes violet with the addition of
hydrochloric acid HCL to distinguish lead from heavy metals
Detecting Primer Residue on Hands - ANSWERS-•Gunpowder and primer residue also blows
back toward shooter when a gun is fired
Early tests focus on the detection of nitrates from gunpowder - ANSWERS-False positives
possible since blue color is also present in
• fertilizers, cosmetics, urine, and tobacco
Diphenylamine color test- - ANSWERS-blue color indicated presence of nitrates
Primers currently manufactured (except .22 caliber ammunitio) - ANSWERS-contain a blend of
lead styphnate, barium nitrate, and antimony sulfide.Deposited on the thumb web or back of
firing hand
Application of an adhesive tape or adhesive to the hand's surface in order to remove any
adhering residue particle - ANSWERS-Swabbing both the firing and nonfiring hands with cotton
that has been moistened with 5 percent nitric acid
• Time for collection is crucial as residue on hand decreases
,Tool mark - ANSWERS-any impression, cut, gouge, or abrasion caused by a tool coming into
contact with another object
What is the main ingredient in ordinary glass? - ANSWERS-sand
Glass that is made stronger than ordinary window glass by introducing stress through rapid
heating and cooling of the glass surface is called - ANSWERS-Tempered Glass
The physical property measured by the formula mass per unit volume is.... - ANSWERS-Density
The bending of a light wave as it passes from one medium to another is referred to as -
ANSWERS-Refraction
Flotation is a method used by scientists to determine the _____ of a particle of glass. -
ANSWERS-density
Immersion is a method used by scientists to determine the _____ of a glass particle - ANSWERS-
Refractive Index
A bright halo that is observed near the border of a particle immersed in a liquid of a different
refractive index is known as - ANSWERS-the becke line
Glass fragments can be analyzed by _______ for additional discrimination information -
ANSWERS-ICP-MS
A computerized database that allows an analyst to obtain information relating to an
automobile's make, model, and year is: - ANSWERS-PDQ
, What is the logical first step in soil analysis? - ANSWERS-Comparison of dried soil sample for
color and texture
The smallest particle of an element that can exist and still retain its identity as that element is
the? - ANSWERS-atom
Which of the following types of light has the most energy? (High energy = highest frequency =
shortest wavelength) - ANSWERS-x-rays
Mass spectrometry is a useful technique for comparing and identifying unknown compounds
because? - ANSWERS-Under carefully controlled conditions, no two substances produce the
same fragmentation pattern
Light amplification by stimulated emission of radiation produces light that has all its waves
pulsating in unison. What is this? - ANSWERS-A laser
The presence of what element differentiates organic compounds from inorganic compounds? -
ANSWERS-carbon
GC, HPLC, and TLC are all analysis techniques that separate molecules based on their ability to
move (partition) between a stationary phase and a mobile phase. This separation technique is
called - ANSWERS-chromatography
A type of radiation composed of a helium atom minus its electrons? - ANSWERS-alpha
Light emitted from a source and separated into its component colors or frequencies? -
ANSWERS-Emission spectra
An emission spectrograph vaporizes samples and heats them to a high temperature to produce
an _____ state in which they emit light. - ANSWERS-Excited State
COMPLETE SOLUTIONS27
Rhodizonate Test - ANSWERS-Test for lead residue around bullet hole
Positive test results in a scarlet color. - ANSWERS-Changes violet with the addition of
hydrochloric acid HCL to distinguish lead from heavy metals
Detecting Primer Residue on Hands - ANSWERS-•Gunpowder and primer residue also blows
back toward shooter when a gun is fired
Early tests focus on the detection of nitrates from gunpowder - ANSWERS-False positives
possible since blue color is also present in
• fertilizers, cosmetics, urine, and tobacco
Diphenylamine color test- - ANSWERS-blue color indicated presence of nitrates
Primers currently manufactured (except .22 caliber ammunitio) - ANSWERS-contain a blend of
lead styphnate, barium nitrate, and antimony sulfide.Deposited on the thumb web or back of
firing hand
Application of an adhesive tape or adhesive to the hand's surface in order to remove any
adhering residue particle - ANSWERS-Swabbing both the firing and nonfiring hands with cotton
that has been moistened with 5 percent nitric acid
• Time for collection is crucial as residue on hand decreases
,Tool mark - ANSWERS-any impression, cut, gouge, or abrasion caused by a tool coming into
contact with another object
What is the main ingredient in ordinary glass? - ANSWERS-sand
Glass that is made stronger than ordinary window glass by introducing stress through rapid
heating and cooling of the glass surface is called - ANSWERS-Tempered Glass
The physical property measured by the formula mass per unit volume is.... - ANSWERS-Density
The bending of a light wave as it passes from one medium to another is referred to as -
ANSWERS-Refraction
Flotation is a method used by scientists to determine the _____ of a particle of glass. -
ANSWERS-density
Immersion is a method used by scientists to determine the _____ of a glass particle - ANSWERS-
Refractive Index
A bright halo that is observed near the border of a particle immersed in a liquid of a different
refractive index is known as - ANSWERS-the becke line
Glass fragments can be analyzed by _______ for additional discrimination information -
ANSWERS-ICP-MS
A computerized database that allows an analyst to obtain information relating to an
automobile's make, model, and year is: - ANSWERS-PDQ
, What is the logical first step in soil analysis? - ANSWERS-Comparison of dried soil sample for
color and texture
The smallest particle of an element that can exist and still retain its identity as that element is
the? - ANSWERS-atom
Which of the following types of light has the most energy? (High energy = highest frequency =
shortest wavelength) - ANSWERS-x-rays
Mass spectrometry is a useful technique for comparing and identifying unknown compounds
because? - ANSWERS-Under carefully controlled conditions, no two substances produce the
same fragmentation pattern
Light amplification by stimulated emission of radiation produces light that has all its waves
pulsating in unison. What is this? - ANSWERS-A laser
The presence of what element differentiates organic compounds from inorganic compounds? -
ANSWERS-carbon
GC, HPLC, and TLC are all analysis techniques that separate molecules based on their ability to
move (partition) between a stationary phase and a mobile phase. This separation technique is
called - ANSWERS-chromatography
A type of radiation composed of a helium atom minus its electrons? - ANSWERS-alpha
Light emitted from a source and separated into its component colors or frequencies? -
ANSWERS-Emission spectra
An emission spectrograph vaporizes samples and heats them to a high temperature to produce
an _____ state in which they emit light. - ANSWERS-Excited State
