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Atoms and Matter (Chemistry) Unit Vocabulary
Concept/Vocabulary
Word
Definition
Matter
Anything that has mass and takes up space
Atom
The building blocks from which everything is made; consists
of a proton, electron, and neutron
Element
A pure substance that cannot be broken down into any other
substances (O = oxygen)
Periodic Table
A table of all the known elements listed by the structure of
their atoms
Compound
A pure substance made up of groups of two or more elements
that are chemically bonded together (H2O = water)
Mixture
Two or more different substances which are mixed but are
not chemically bonded (cinnamon sugar)
Mass
The quantity of matter an object or substance is made up of
Volume
The amount of space a substance occupies
Weight
Mass x gravitational acceleration of the Earth (9.8 m/s2)
Density
Mass divided by Volume (d=m/v)
State of matter
A form in which matter can exist (solid, liquid, gas, or plasma)
Gas
A state of matter in which the atomic particles are far apart;
no definite shape, no definite volume
Liquid
A state of matter in which the atomic particles are in small
clusters but can move apart from each other; no definite
shape, definite volume
Solid
A state of matter in which the atomic particles vibrate, but
do not move and are bonded together; definite shape,
definite volume
Plasma
Gas-like substance made up of positively and negatively
charged particles
Condensation
The process by which a gas turns into a liquid
Evaporation
The process by which a liquid turns into a gas
Melting
The process by which a solid turns into a liquid
Freezing
The process by which a liquid turns into a solid
Sublimation
The process by which a solid turns into a gas (e.g., dry ice)
Deposition
The process by which a gas turns into a solid (e.g, snow)
Physical change
An action which does NOT cause a change to the molecular
composition of the substance (e.g., water freezing into ice)
Chemical change
An action which causes a change to the molecular composition
of a substance (e.g, a log burning into ash)