Forensic Science Chapter 4 5 Flashcards

Terms Definitions
physical property
The behavior of a substance without alteration of the substance's composition through a chemical reaction.
chemical property
The behavior of a substance when it reacts or combines with another substance
Fahrenheit scale
The temperature scale using the melting point of ice as 32° and the boiling point of water as 212°, with 180 equal divisions or degrees between
Celsius scale
The temperature scale using the melting point of ice as 0° and the boiling point of water as 100°, with 100 equal divisions or degrees between
weight
A property of matter that depends on both the mass of a substance and the effects of gravity on that mass
mass
A constant property of matter that reflects the amount of material present
density
A physical property of matter that is equivalent to the mass per unit volume of a substance
intensive property
A property that is not dependent on the size of an object
refraction
The bending of a light wave as it passes from one medium to another
refractive index
The ratio of the speed of light in a vacuum to its speed in a given substance
crystalline solid
A solid in which the constituent atoms have a regular arrangement
atom
The smallest unit of an element, which is not divisible by ordinary chemical means; atoms are made up of electrons, protons, and neutrons plus other subatomic particles
amorphous solid
A solid in which the constituent atoms or molecules are arranged in random or disordered positions; there is no regular order in amorphous solids
birefringence
A difference in the two indices of refraction exhibited by most crystalline materials
dispersion
The separation of light into its component wavelengths
tempered glass
Glass that is strengthened by introducing stress through rapid heating and cooling of the glass surfaces
laminated glass
Two sheets of ordinary glass bonded together with a plastic film
Becke line
A bright halo that is observed near the border of a particle immersed in a liquid of a different refractive index
radial fracture
A crack in a glass that extends outward like the spoke of a wheel from the point at which the glass was struck
concentric fracture
A crack in a glass that forms a rough circle around the point of impact
mineral
A naturally occurring crystalline solid
matter
All things of substance; matter is composed of atoms or molecules
element
A fundamental particle of matter; an element cannot be broken down into simpler substances by chemical means
Periodic table
A chart of elements arranged in a systematic fashion; vertical rows are called groups or families, and horizontal rows are called series; elements in a given row have similar properties
compound
A pure substance composed of two or more elements
physical state
A condition or stage in the form of matter; a solid, liquid, or gas
solid
A state of matter in which the molecules are held closely together in a rigid state
liquid
A state of matter in which molecules are in contact with one another but are not rigidly held in place
gas ( vapor)
A state of matter in which the attractive forces between molecules are small enough to permit them to move with complete freedom
phase
A uniform body of matter; different phases are separated by definite visible boundaries
organic
Describes a substance composed of carbon and often smaller amounts of hydrogen, oxygen, nitrogen, chlorine, phosphorus, or other elements
inorganic
Describes a chemical compound not based on carbon
spectrophotometry
An analytical method for identifying a substance by its selective absorption of different wavelengths of light
chromatography
Any of several analytical techniques for separating organic mixtures into their components by attraction to a stationary phase while being propelled by a moving phase
prolysis
The decomposition of organic matter by heat
fluoresce
To emit visible light when exposed to light of a shorter wavelength— that is, ultraviolet light
electrophoresis A
technique for separating molecules through migration on a support medium while under the influence of an electrical potential
visible light
Colored light ranging from red to violet in the electromagnetic spectrum
wavelength
The distance between crests of adjacent waves
frequency
The number of waves that pass a given point per second
electromagnetic spectrum
The entire range of radiation energy from the most energetic cosmic rays to the least energetic radio waves
X- ray
A high- energy, short- wavelength form of electromagnetic radiation
laser
An acronym for light amplification by stimulated emission of radiation; light that has all its waves pulsating in unison
photon
A small packet of electromagnetic radiation energy; each photon contains a unit of energy equal to the product of Planck's constant and the frequency of radiation: E hf
monochromator
A device for isolating individual wavelengths or frequencies of light
monochromatic light
Light having a single wavelength or frequency
ultraviolet
Invisible long frequencies of light beyond violet in the visible spectrum
infrared
Invisible short frequencies of light before red in the visible spectrum
ion
An atom or molecule bearing a positive or negative charge
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