Active Chemistry Vocabulary Definitions (alpha sort)

accuracy
How close the measured value is to the standard or accepted value of that measurement.
acid base indicator
A dye that has a certain color in an acid solution and a different color in a base solution. 3.2
acid
A substance that produces hydrogen ions in water, or is a proton donor. 3.7
alloy
A substance that has metal characteristics and consists of two or more different elements. 1.6
amorphous solid
A solid that lacks a well-defined crystal structure. 1.6
anion
A negatively charged ion. 3.3
atom
The smallest representative part of an element.
atomic mass
Determined by the mass of protons and neutrons in the atom. 2.3
atomic mass unit
1/12 the mass of a C-12 atom. 2.3
atomic orbital
A region in space where electrons on an atom can be found. 2.5
Avogadro's number
The number of atoms in 12 g of carbon-12. 6.022 x 1023. 2.3
base
A substance that releases hydroxide ions (-OH) in water or is a proton acceptor. 3.7
binary compound
Chemical compound composed of only two elements. 2.8
catalyst
A substance that increases the rate of a chemical reaction, without being changed itself in the reaction. 3.6
cation
A positively charged ion. 3.3
ceramics
Objects made of baked clay, such as vases and other forms of pottery, tiles, and small sculptures.
chemical change
The change of substances into other substances, with different chemical composition, through a reorganization of the atoms; a chemical reaction. 3.1
chemical equation
Summary of a chemical reaction using chemical formulas for reactants and products.
chemical formula
Notation that uses atomic symbols in a definite numerical proportion to convey the relative proportions of atoms of the different elements in the substance. 1.1
chemical group
A family of elements in the periodic table that have similar electron configurations. 2.6
chemical property
Observed when a substance undergoes a transformation into one or more new substances. 2.2
chemical reaction
A change in the arrangement of atoms or molecules to yield substances of different composition and properties. 3.1
chemical test
Procedure or chemical reaction used to identify a substance. 3.2
colloid
Very finely divided solid particles which will not settle out of a solution; intermediate between a true dissolved particle and a suspended solid which will settle out of solution. 1.3
combustion
Chemical reaction between a fuel and oxygen that produces heat (and usually, light). 1.9
composite
A material made from two or more different types of material which contribute different properties. 1.4
compound
A substance formed by a union of two or more elements in a definite proportion by weight. 1.1
concentration
Measure of the amount of dissolved material (solute) in a solution. It can be expressed in moles of solute per liter of solution. 3.1
conductivity
The property of transmitting heat and electricity. 1.6
controlled variable
Quantities that a scientist wants to remain constant. These are all the things that you will keep the same in your experiment.
covalent bond
A bond between two atoms formed by the sharing of a pair of electrons. 2.8
decomposition.
A chemical reaction in which a single compounds reacts to yield two or more products. 3.4
density
Mass per unit volume of a substance. 1.5
double-displacement reaction.
A chemical reaction in which two ionic compounds exchange cations to produce two new compounds. 3.4
ductility
A physical property describing how easy it is to pull a substance into a new permanent shape. 1.6
elasticity
A physical property of a material to resist deformation and return to its normal size or shape after a force has been applied to it. 1.4
electrolysis
Process in which an electric current flowing through a solution or molten compound breaks that compound up into its component parts. 1.1
electromagnet
Coil of wire that is wrapped around a soft iron core that is magnetized when electric current flows through it.
electromagnetic forces
Force that arises between particles with electric charge; the second strongest of the four fundamental forces.
electromagnetic spectrum
Full range of frequencies, from radio waves to gamma rays, that characterizes light. The low end of the spectrum is infrared radiation (heat), and passes through the colors of visual light from red through violet, through ultraviolet radiation, x-rays, and gamma rays. 2.5
electron configuration
The arrangement of electrons in atomic orbitals; for example, 1s2 2s2 2p3.     2.6
electron
A subatomic particle that occurs outside of the nucleus and has a charge of -1.
electron orbit
The path of the electron in its motion around the nucleus of Bohr's hydrogen atom. 2.5
element
A substance in which all of the atoms have the same atomic number.
emulsion
A colloid or colloidal dispersion of one liquid suspended in another. 1.4
endothermic reaction
Reaction that absorbs heat from its surroundings as the reaction proceeds. 3.5
exothermic reaction
A reaction during which chemical energy is released in the form of heat. 3.5
fission
The process whereby the nucleus of a particular heavy element splits into (generally) two nuclei of lighter elements, with the release of substantial amounts of energy. 2.9
flame test
An experimental technique or process in identifying a metal from its characteristic flame color. 1.8
frequency
The number of back-and-forth cycles per second, in a wave or wave-like process.
fusion
A nuclear reaction in which nuclei combine to form more massive nuclei with the simultaneous release of energy. 2.9
g/cm3
A unit of density. 1.5
g/cm3
A unit of density. 1.5
g
A metric unit of weight equal to one thousandth of a kilogram. One gram.
gram
A metric unit of weight equal to one thousandth of a kilogram.
halogens
Elements that constitute Group VIIB of the Periodic Table of Elements: fluorine, chlorine, bromine, iodine and astatine. 2.8
heterogeneous
A substance having different characteristics in different locations. 1.3
hydrocarbon
An organic compound containing only carbon and hydrogen. 1.9
infrared radiation
Electromagnetic radiation with wavelengths greater than those of the visible light but shorter than those of microwaves it is associated with heat energy.
inorganic compound
any compound that does not contain carbon. 1.9
inputs
The resources that are necessary to carry out activities of a system.
insoluble
A substance that does not dissolve in a solvent to give a reasonable concentration. 1.3
ion
An atom or group of atoms that carries a positive or negative electric charge as a result of having lost or gained one or more electrons. 1.8
ionic bond
An attraction between oppositely charged ions. 2.8
ionic compound
A compound consisting of positive and negative ions. 3.3
ionization energy
The energy required to remove an electron from a gaseous atom at ground state. 3.3
isotope
Atoms of the same element but different atomic masses due to different number of neutrons. 2.9
kg
SI symbol of kilogram.
kinetic energy
A form of energy related to the motion of a particle (KE=½mv2). 1.2
law of definite proportions
Different samples of a pure compound always contain the same elements in the same proportions by mass. 2.3
luster
The light reflective quality of fiber exhibited in shine and gloss. 1.6
malleability
The property of a material to be able to be hammered into various shapes without breaking. 1.4
manipulated variable
The variable you will change in your experiment.
mass
The property of a body that causes it to have weight in a gravitational field.
matter
That which has mass and occupies space.
m
SI symbol of meter.
metal
Classes of materials that exhibit properties of conductivity, malleability, and ductility, These elements tend to lose electrons to form positive ions. 1.6
milliliter
1/1000 of a liter.
mixtures
a substance consisting of two or more substances mixed together (not in fixed proportions and not with chemical bonding). 1.3
mL
SI symbol of milliliter.
molecular compound
Two or more atoms bond together by sharing electrons (covalent bond). 3.3
mole
A collection of objects that contains Avogadro's number of objects. (6.02 x 1023). 2.3
neutralization
The process of an acid and base reacting to form water and salt. 3.7
neutron
Neutral subatomic particle located in the nuclei of the atom. Has a mass of 1.675 x 10-24g.
Newton
Unit of force, the force which, when applied to one kilogram mass, causes an acceleration of 1 meter/sec2.
noble gas
Any of a group of rare gases that include helium, neon, argon, krypton, xenon, and radon and that exhibit great chemical stability Group 18 on the periodic table. 2.7
nonmetal
Classes of materials that do not exhibit properties of conductivity, malleability, and ductility, These elements tend to gain electrons to form negative ions. 1.6
normal boiling point
The characteristic temperature, at 1 atm, at which a material changes from a liquid state to its gaseous state. Also the temperature at which the vapor pressure of the pure liquid equals 1 atm. 1.2
normal freezing point
The characteristic temperature, at 1 atm, at which a material changes from a liquid state to its solid state. 1.2
normal melting point
The characteristic temperature, at 1atm, at which material changes from a solid state to its liquid state. 1.2
nuclear energy
Energy or power produced by nuclear reactions (fusion or fission).
nuclear force
That force exerted by subatomic particles that is responsible for form, shape, and motion of particles in the atom. 2.9
nucleus
The very dense core of the atom that contains the neutrons and protons. 1.8
organic compound
A molecular compound of carbon other than carbonates and cyanides and carbon dioxide. 1.9
oxidation
The process of a substance losing one or more electrons. 1.6
oxidation number
A number assigned to an element in a compound designating the number of electrons that element has lost gained, or shared in forming that compound. 3.3
period
A horizontal row of elements in the periodic table. 2.6
phase change
The conversion of a substance from one state to another state at a specific temperature and pressure. 1.2
pH
A quantity used to represent the acidity of a solution based on the concentration of hydrogen ions. 3.7
physical change
A change that involves changes in the state or form of a substance but does not cause an change in the chemical composition. 2.2
physical property
A property that can be measured without causing a change in the substances chemical composition. 2.2
Plank's constant
A proportionality constant of the energy of a photon to its frequency, E=hf = 6.62 x 10-34J/s. 2.5
polyatomic ion
An ion that consists of 2 or more atoms that are covalently bonded and have either a positive or negative charge. 3.3
polymer
A substance that is a macromolecule consisting of many similar small molecules (monomers) linked together. 1.7
polymerization
A chemical reaction that converts small molecules (monomers) into much larger molecules (polymers). 1.7
potential energy
Stored energy of a material a a result of its position in an electric, magnetic, or gravitational field. PE=mgh. 1.2
precipitate
An insoluble solid formed in a liquid solution as a result of some chemical reactions. 3.1
precision
The closeness of agreement of several measurements of the same quantity. 1.5
product
The substance produced in a chemical reaction. 1.1
proton
A positively charged subatomic particle contained in the nucleus of an atom. The charge is +1 and a mass of 1.673 x 10-24g.
pure material
An element or compound that has a defined composition and properties. 1.3
pure substance
A substance that contains only one kind of particle. 1.3
radioactive
An atom that has an unstable nuclei and will emit alpha, positron, or beta particles in order to achieve more stable nuclei. 2.9
reactants
The starting materials in a chemical reaction. 1.1
reactivity
A property that describes how readily a material will react with other materials. 1.6
reduction
A process in which the substance under consideration gains electron(s). 3.8
responding variable
The measured quantity that changes when you change the manipulated variable in a scientific investigation.
saturated solution
The maximum amount of solution that can be dissolved at a given temperature and pressure. 3.1
single-displacement reaction.
A chemical reaction in which an element replaces another element in a compound. 3.4
solute
The substance that dissolves in a solvent to form a solution. 1.3
solution
A homogeneous mixture of two or more substances. 1.3
solvent
The substance in which a solute dissolves to form a solution. 1.3
sublimation
The changed of state of a solid material to a gas without going through the liquid state. 1.2
supersaturated solution
A solution containing more solute than a saturated solution and therefore not at equilibrium. This solution is not stable and cannot be maintained indefinitely. 3.1
surface area
Changing the nature of the reactants into smaller particles increases the surface exposed to react. 3.6
suspension
Heterogeneous mixture that contains fine solid or liquid particles in a fluid that will settle out spontaneously. 1.3
synthesis reaction.
When two or more substances combine to form a new compound. 3.4
temperature
The measure of average kinetic energy of all the particles of material. 3.5
texture
The characteristics of the surface of a material, like how smooth, rough, or coarse it is. 1.4
Tyndall effect
The scattering of a light beam as it passes through a colloid. 1.3
uniformity
The property of how consistent a material is throughout. 1.4
valence electrons
The outermost electrons of an atom. These electrons are involved in chemical bonding of atoms. 2.7
vaporization
The change of state from a liquid to a gas. 1.2
viscosity
A property related to the resistance of a fluid to flow. 1.7
wavelength
The distance measured from crest to crest of one complete wave or cycle.