Intro to Chemistry

Alloy
a homogeneous mixture of two or more metals
Atom
indivisible, spherical particles
Atomic Number
number that identifies a particular element
Chemical Change
composition of the sample changes in which there is a chemical change
Chemical Formula
expresses the number of atoms of each element in a compound
Chemical Property
describes its chemical reactions with other substances
Chemical Symbol
Abbreviated name of each element
compound
predictable properties that can be broken down into elements by an ordinary chemical reaction
deposition
a direct change of state from a gas to a solid
ductile
If a metal can be drawn into a fine wire
element
a substance that cannot be broken down further by a chemical reaction
Heterogeneous Mixture
can be separated into pure substances by physical methods
Homogeneous Mixture
constant for a given sample
Kinetic Energy
the energy matter has a result of its motion
Law of Conservation of Energy
energy can be converted from one form to another
Law of Conservation of Mass
matter was neither created nor destroyed during a chemical reaction
Law of Conservation of Mass and Energy
total mass and energy in the universe is constant
Law of Definite Composition
Compounds always contain the same elements in a constant proportion by mass
Malleable
Metal that can be hammered into a thin sheet of foil
Metal
element that is typically a solid, has bright metallic luster, a high density, a high melting point and is a good conductor of heat and electricity.
Molecule
a unit of matter composed of two or more nonmetal atoms
Nonmetal
an element that usually has a low density a low melting point and is a poor conductor of heat and electricity
Periodic Table
all the elements that have been arranged by atomic number and placed in a special chart
Physical Change
chemical composition of the sample does not change
Physical Property
those characteristics of a pure substance that we can observe without changing the composition of the substance
Physical State
solid, liquid or gas
Potential Energy
stored energy that matter possesses as a result of its position or composition
Semimetal
an element that typically has properties midway between those of metals and nonmetals
Sublimation
a direct change of state from a solid to a gas
Substance
matter that has definite composition and constant properties