Chemistry: A Molecular Approach Chapter
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atom - ANSA submicroscopic particle that constitutes the fundamental building block of ordinary
matter; the smallest identifiable unit of an element.
molecule - ANSTwo or more atoms joined chemically in a specific geometrical arrangement.
chemistry - ANSThe science that seeks to understand the behavior of matter by studying the
behavior of atoms and molecules.
hypothesis - ANSA tentative interpretation or explanation of an observation. A good one is
falsifiable.
experiment - ANSA highly controlled procedure designed to generate observations that may
support a hypothesis or prove it wrong.
scientific law - ANSA brief statement or equation that summarizes past observations and
predicts future ones.
law of conservation of mass - ANSA law stating that matter is neither created nor destroyed in a
chemical reaction.
atomic theory - ANSThe theory that each element is composed of tiny indestructible particles
called atoms, that all atoms of a given element have the same mass and other properties, and
that atoms combine in simple, whole-number ratios to form compounds.
scientific method - ANSAn approach to acquiring knowledge about the natural world that begins
with observations and leads to the formation of testable hypotheses.
matter - ANSAnything that occupies space and has mass.
substance - ANSA specific instance of matter such as air, water, or sand.
state - ANSA classification of the form of matter as a solid, liquid, or gas.
composition - ANSThe basic components that make up matter.
solid - ANSA state of matter in which atoms or molecules are packed close to one another in
fixed locations with definite volume.
, liquid - ANSA state of matter in which atoms or molecules pack about as closely as they do in
solid matter but are free to move relative to each other, giving a fixed volume but not a fixed
shape.
gas - ANSA state of matter in which atoms or molecules have a great deal of space between
them and are free to move relative to one another; lacking a definite shape or volume, this
conforms to those of its container.
crystalline solid (crystal) - ANSA solid in which atoms, molecules, or ions are arranged in
patterns with long-range, repeating order.
amorphous solid - ANSA solid in which atoms or molecules do not have any long-range order.
pure substance - ANSA substance composed of only one type of atom or molecule.
mixture - ANSA substance composed of two or more different types of atoms or molecules that
can be combined in variable proportions.
element - ANSA substance that cannot be chemically broken down into simpler substances.
compound - ANSA substance composed of two or more elements in fixed, definite proportions.
heterogeneous mixture - ANSA mixture in which the composition varies from one region to
another.
homogeneous mixture - ANSA mixture with the same composition throughout
decanting - ANSA method of separating immiscible liquids by pouring the top layer into another
container.
distillation - ANSThe process by which mixtures of miscible liquids are separated by heating the
mixture to boil off the more volatile liquid. The vaporized component is then recondensed and
collected in a separate flask.filtration
volatile - ANSTending to vaporize easily.
filtration - ANSA process used to separate a mixture composed of an insoluble solid and a liquid
by pouring it through filter paper or some other porous membrane or layer.
physical change - ANSA change that alters only the state or appearance of a substance but not
its chemical composition.
chemical change - ANSA change that alters the molecular composition of a substance; see also
chemical reaction
1
atom - ANSA submicroscopic particle that constitutes the fundamental building block of ordinary
matter; the smallest identifiable unit of an element.
molecule - ANSTwo or more atoms joined chemically in a specific geometrical arrangement.
chemistry - ANSThe science that seeks to understand the behavior of matter by studying the
behavior of atoms and molecules.
hypothesis - ANSA tentative interpretation or explanation of an observation. A good one is
falsifiable.
experiment - ANSA highly controlled procedure designed to generate observations that may
support a hypothesis or prove it wrong.
scientific law - ANSA brief statement or equation that summarizes past observations and
predicts future ones.
law of conservation of mass - ANSA law stating that matter is neither created nor destroyed in a
chemical reaction.
atomic theory - ANSThe theory that each element is composed of tiny indestructible particles
called atoms, that all atoms of a given element have the same mass and other properties, and
that atoms combine in simple, whole-number ratios to form compounds.
scientific method - ANSAn approach to acquiring knowledge about the natural world that begins
with observations and leads to the formation of testable hypotheses.
matter - ANSAnything that occupies space and has mass.
substance - ANSA specific instance of matter such as air, water, or sand.
state - ANSA classification of the form of matter as a solid, liquid, or gas.
composition - ANSThe basic components that make up matter.
solid - ANSA state of matter in which atoms or molecules are packed close to one another in
fixed locations with definite volume.
, liquid - ANSA state of matter in which atoms or molecules pack about as closely as they do in
solid matter but are free to move relative to each other, giving a fixed volume but not a fixed
shape.
gas - ANSA state of matter in which atoms or molecules have a great deal of space between
them and are free to move relative to one another; lacking a definite shape or volume, this
conforms to those of its container.
crystalline solid (crystal) - ANSA solid in which atoms, molecules, or ions are arranged in
patterns with long-range, repeating order.
amorphous solid - ANSA solid in which atoms or molecules do not have any long-range order.
pure substance - ANSA substance composed of only one type of atom or molecule.
mixture - ANSA substance composed of two or more different types of atoms or molecules that
can be combined in variable proportions.
element - ANSA substance that cannot be chemically broken down into simpler substances.
compound - ANSA substance composed of two or more elements in fixed, definite proportions.
heterogeneous mixture - ANSA mixture in which the composition varies from one region to
another.
homogeneous mixture - ANSA mixture with the same composition throughout
decanting - ANSA method of separating immiscible liquids by pouring the top layer into another
container.
distillation - ANSThe process by which mixtures of miscible liquids are separated by heating the
mixture to boil off the more volatile liquid. The vaporized component is then recondensed and
collected in a separate flask.filtration
volatile - ANSTending to vaporize easily.
filtration - ANSA process used to separate a mixture composed of an insoluble solid and a liquid
by pouring it through filter paper or some other porous membrane or layer.
physical change - ANSA change that alters only the state or appearance of a substance but not
its chemical composition.
chemical change - ANSA change that alters the molecular composition of a substance; see also
chemical reaction
