Forensics Review Questions ch. 5

matter

Anything that has mass and occupies space is defined as ________

elements

The basic building blocks of all substances are the ______

118

The number of elements known today is ______

periodic

An arrangement of elements by similar chemical properties is accomplished in the ______ table

atom

An _____ is the smallest particle of an element that can exist

compound

Substances composed of two or more elements are called ______

molecule

A ______ is the smalles unit of a compound formed by the union of two or more atoms

solid

The physical state that retains a definite shape and volume is a __________

has no

A gas (has, has no) definite shape or volume.

sublimation

During the process of ________, solids go directly to the gaseous state, bypassing the liquid state

less

The attraction forces between the molecules of a liquid are (more, less) thatn those in a solid

substances

Different ______ are seperated by definite visible boundaries

organic

Carbon-containing substances are classified as _____.

inorganic

______ substances encompass all non-carbon-containing materials.

qualitative; quantitative

A ______ analysis describes the identity of a material, and a ______ analysis relates to a determination of the quantity of a substance.

spectrophotometry

The study of the absorption of light by chemical substances is known as _______.

chromatography

A mixture's components can be separated by the technique of _______.

true

True or False: Henry's law describes the distribution of a volatile chemical compound between its liquid and gas phases.

higher

The (higher, lower) the solubility of a gas in a liquid, the greater its tendency to remain dissolved in that liquid

true

True of False: In order for chromatography to occur, one phase must move continuously in one direction over a stationary phase.

gas chromatography

A technique that separates mixtures on the basis of their distribution between a stationary liquid phase and a moving gas phase is _______

retention time

The time required for a substance to travel through the gas chromatographic column is a useful identifying characteristic known as ______

pyrolyzed

Solid materials that are not readily dissolved in solvents for injection into the gas chromatograph can be ______ into numerous gaseous products prior to entering the gas chromatograph

room

A major advantage of high-performance liquid chromatography is that the entire process takes place at ______ temperature

thin-layer chromatography

A technique that uses a moving liquid phase and a stationary solid phase to separate mixtures is _____

visualized

Because most chemical compounds are colorless, the final step of the thin-layer development usually requires that they be _____ by spraying with a chemical reagent

Rf

The distance a spot has traveled up a thin-layer plate can be assigned a numerical value known as the _____ value.

false

True of False: Thin-layer chromatography yields the positive identification of a materia.

electrophoresis

The migration of materials along a stationary phase under the influence of an electrical potential describes the technique of ______

true

True or False: Color is a usual indication that substances selectively absorb light.

wavelength

The distnace between two successive identical points on a wave is known as _____

false

True or False: Frequency and wavelength are directly proportional to one another

electromagnetic

Light, X-rays, and radio waves are all members of the _____ spectrum

lower

Red light is (higher, lower) in frequency than violet light

laser

Light that has all its waves pulsating in unison is called a ______

electromagnetic spectrum

One model of light depicts it as consisting of energy particles known as a

true

True or False: The energy of a light particle is directly proportional to its frequency.

more

Red light is (more, less) energetic that violet light

can

The selective absorption of electromagnetic radiation by materials (can, cannot) be used as an aid for identification

Beer's

The amount of radiation a substances will absorb is directly proportional to its concentration as defined by _____ law

spectrophotometer

The ____ is the instrument used to measure and record the absorption spectrum of a chemical substance

spectrometer

The function of the ______ is to select a single frequency of light emanating from the spectrophotometer's source

infrared

An _______ absorption spectrum provides a unique "fingerprint" of a chemical substance

monochromator

The technique of _____ exposes molecules to a beam of high-energy electrons in order to fragment them

true

True or False: A mass spectrum is normally considered a specific means for identifying a chemical substance.