Download Flashcards - Chemistry - Muoio-Physical-Science-Wiki

Substance
Element or compound that cannot be broken down
into simpler components and maintain the
properties of the original substance.
Element
Substance with atoms that are all alike.
Compound
Substance formed from two or more elements in
which the exact combination and proportion of
elements is always the same.
Heterogeneous mixture
Mixture, such as mixed nuts or a dry soup mix, in
which different materials are unevenly distributed
and are easily identified.
Homogeneous mixture
Solid, liquid or gas that contains two or more
substances blended evenly throughout.
Solution
Homogeneous mixture that remains constantly and
uniformly mixed and has particles that are so small
they cannot be seen with a microscope.
Colloid
Heterogeneous mixture whose particles never
settle.
Suspension
Heterogeneous mixture containing a liquid in which
visible particles settle
Physical property
Any characteristic of a material, such as size or
shape, that you can observe or attempt to observe
without changing the identity of the material.
Physical change
Any change in size, shape or state or matter in
which the identity of the substance remains the
same.
Chemical property
Chemical change
Any characteristic of a substance, such as
flammability, that indicates whether it can
undergo a certain chemical change.
Change where the starting material is
changed into a new substance giving or heat,
light, forming a precipitate (solid), producing
a gas, or changing color.
Law of conservation of mass
States that the mass of all substances present
before a chemical change equals the mass of
all the substances remaining after the change.
Mass of the reactants equal the mass of the
products.
Kinetic theory
Explanation of behavior of molecules in
matter, states that all matter is made of
constantly moving particles that collide
without using energy.
Melting point
Temperature at which a solid begins to
liquefy.
Boiling point
The temperature at which the pressure of the
vapor in the liquid is equal to the external
pressure acting on the surface.
Plasma
Matter consisting of positively and negatively
charged particles. The type of matter that has
the highest Kinetic energy.
Atom
The smallest particle of an element that still
has the same properties of the element; the
smallest unit of matter.
Nucleus
The center of an atom that contains 99.99%
of an atoms mass.
Proton
A particle located in the nucleus of an atom
that has a positive charge.
Neutron
A particle located in the nucleus of an atom
that has no charge. You can find this particle
by taking the mass number of an element
minus the number of protons.
Electron
Particles outside of the nucleus that have a
negative charge.
Solid
The state of matter that has a definite volume
and a definitive shape. It also has the lowest
kinetic energy out of all of the four states of
matter.
Liquid
The state of matter that has a definite volume
but no definite shape.
Atomic number
Number of protons in an atom’s nucleus.
Mass number
Sum of the number of protons and neutrons
in an atoms nucleus.
Isotope
Atoms of the same element that have
different number of neutrons.
Average atomic mass
Weighted average mass of the mixture of an
element’s isotopes.
Periodic table
Organized list of all known elements that are
arranged by increasing atomic numbers and
by their physical and chemical properties.
Group
Vertical row on the periodic table
Period
Horizontal row on the periodic table.
Gas
The state of matter that has no definite
volume or shape.
Strong force
Attractive force that acts between protons
and neutrons to form the nucleus of an atom
Radioactivity
Process that occurs when a nucleus decays
and emits alpha, beta or gamma radiation.
Alpha particle
Particle consisting of two protons and two
neutrons that is emitted from a decaying
atomic nucleus, whose energy can be stopped
by a piece of paper.
Transmutation
The process of changing one element into
another through radioactive decay.
Beta particle
Electron that is emitted from a decaying
atomic nucleus that has an energy that can be
stopped by lead that is 1 cm thick.
Gamma ray
Electromagnetic wave with no mass and no
charge that travels the speed of light and has
an energy that can be stopped by a concrete
wall.
Half-life
Amount of times it takes for half the nuclei in
a sample of a radioactive isotope to decay.
Endothermic Reaction
A reaction where the products absorb
energy, such as a nail collecting rust.
Exothermic Reaction
A reaction where the products release energy
into the atmosphere be means of heat, light
or gas.
Geiger counter
Radiation detector that produces a click or
flash of light when a charged particle is
detected.
Nuclear fission
Process of splitting an atomic nucleus into
two or more nuclei with smaller masses.
Nuclear fusion
Reaction in which two or more atomic nuclei
form a nucleus with a larger mass.
Chain reaction
Ongoing series of fission reactions.
Critical mass
Amount of fissionable material required so
that each fission reaction produces
approximately one more fission reaction.
Metal
Element that typically is a hard, shiny solid, is
malleable, and is a good conductor of heat
and electricity.
Malleable
The ability of metals to be hammered or
rolled into thin sheets.
Ductile
The ability of metals to be drawn into wires.
Sublimation
Going from a solid directly to a gas. Dry Ice
is a well known example of this.
Salt
Compound formed when negative ions from
an acid combine with positive ions from a
base.
Metalloid
An element that shares some properties with
metals and other properties with non-metals.
Usually used when building computers.
Chemical formula
Chemical shorthand that uses symbols to tell
what elements are in a compound and their
ratios.
Chemical bond
The force that holds atoms together in a
compound
Ion
A charged particle that has either fewer or
more electrons than protons.
Ionic bond
A type of bond where the attraction formed
between oppositely charged ions transfer
electrons to form a stable bond.
Covalent bond
A type of bond where the attraction formed
between atoms share electrons.
Molecule
A neutral particle that forms as a result of
electron sharing.
Oxidation number
Positive or negative number that indicates
how many electrons an atom has to gain,
lose, or share in order to become stable.
Chemical reaction
The process in which one or more
substances are changed into new substances.
Reactant
In a chemical equation, the substance that
reacts.
Solute
The part of a solution that is dissolved by the
solvent.
Solvent
A part of a solution that dissolves the solute.
Solution
Homogeneous mixture of two or more
substances. An example would be salt water.
Product
In a chemical reaction, the new substance
that is formed.
Synthesis Reaction
Chemical reaction in which two or more
substances combine to form a different
substance
A + B  AB
Decomposition Reaction
Chemical reaction in which one substance
breaks down into two or more substances.
AB  A + B
Single Replacement Reaction
A chemical reaction in which one element
replaces another element in a compound
A + BC  AC + B
Double Replacement Reaction
Chemical reaction that where both beginning
elements replace each other to form new
products.
AC + BD  AD + BC
Base
A compound that has a pH over 7 and tends
to feel slippery, be corrosive and cause
burns.
Neutral Solution
A solution that has a pH of 7. An example is
pure water.
Acid
A compound that has a pH under 7 and
tends to taste sour, and cause burns.
Chemical equation
Shorthand method to describe chemical
reactions using chemical formulas and other
symbols.
Coefficient
Number in a chemical equation that
represents that number of units of each
substance taking part in a chemical reaction.