Active Chemistry Vocabulary Definitions Table

accuracy How close the measured value is to the standard or accepted value of that measurement.
atom The smallest representative part of an element.
ceramics Objects made of baked clay, such as vases and other forms of pottery, tiles, and small sculptures.
chemical equation Summary of a chemical reaction using chemical formulas for reactants and products.
controlled variable Quantities that a scientist wants to remain constant. These are all the things that you will keep the same in your experiment.
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.
electron A subatomic particle that occurs outside of the nucleus and has a charge of -1.
element A substance in which all of the atoms have the same atomic number.
frequency The number of back-and-forth cycles per second, in a wave or wave-like process.
g SI symbol of gram.
gram A metric unit of weight equal to one thousandth of a kilogram.
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.
inputs The resources that are necessary to carry out activities of a system.
kg SI symbol of kilogram.
m SI symbol of meter.
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.
milliliter 1/1000 of a liter.
mL SI symbol of milliliter.
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.
nuclear energy Energy or power produced by nuclear reactions (fusion or fission).
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.
responding variable The measured quantity that changes when you change the manipulated variable in a scientific investigation.
wavelength The distance measured from crest to crest of one complete wave or cycle.
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
compound A substance formed by a union of two or more elements in a definite proportion by weight. 1.1
electrolysis Process in which an electric current flowing through a solution or molten compound breaks that compound up into its component parts. 1.1
product The substance produced in a chemical reaction. 1.1
reactants The starting materials in a chemical reaction. 1.1
kinetic energy A form of energy related to the motion of a particle (KE=½mv2). 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
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
phase change The conversion of a substance from one state to another state at a specific temperature and pressure. 1.2
potential energy Stored energy of a material a a result of its position in an electric, magnetic, or gravitational field. PE=mgh. 1.2
sublimation The changed of state of a solid material to a gas without going through the liquid state. 1.2
vaporization The change of state from a liquid to a gas. 1.2
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
heterogeneous A substance having different characteristics in different locations. 1.3
insoluble A substance that does not dissolve in a solvent to give a reasonable concentration. 1.3
mixtures a substance consisting of two or more substances mixed together (not in fixed proportions and not with chemical bonding). 1.3
pure substance A substance that contains only one kind of particle. 1.3
pure material An element or compound that has a defined composition and properties. 1.3
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
suspension Heterogeneous mixture that contains fine solid or liquid particles in a fluid that will settle out spontaneously. 1.3
Tyndall effect The scattering of a light beam as it passes through a colloid. 1.3
composite A material made from two or more different types of material which contribute different properties. 1.4
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
emulsion A colloid or colloidal dispersion of one liquid suspended in another. 1.4
malleability The property of a material to be able to be hammered into various shapes without breaking. 1.4
texture The characteristics of the surface of a material, like how smooth, rough, or coarse it is. 1.4
uniformity The property of how consistent a material is throughout. 1.4
density Mass per unit volume of a substance. 1.5
g/cm3 A unit of density. 1.5
precision The closeness of agreement of several measurements of the same quantity. 1.5
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
conductivity The property of transmitting heat and electricity. 1.6
ductility A physical property describing how easy it is to pull a substance into a new permanent shape. 1.6
luster The light reflective quality of fiber exhibited in shine and gloss. 1.6
metal Classes of materials that exhibit properties of conductivity, malleability, and ductility, These elements tend to lose electrons to form positive ions. 1.6
nonmetal Classes of materials that do not exhibit properties of conductivity, malleability, and ductility, These elements tend to gain electrons to form negative ions. The oxides of these elements are acidic. 1.6
oxidation The process of a substance losing one or more electrons. 1.6
reactivity A property that describes how readily a material will react with other materials. 1.6
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
viscosity A property related to the resistance of a fluid to flow. 1.7
flame test An experimental technique or process in identifying a metal from its characteristic flame color. 1.8
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
nucleus The very dense core of the atom that contains the neutrons and protons. 1.8
combustion Chemical reaction between a fuel and oxygen that produces heat (and usually, light). 1.9
hydrocarbon An organic compound containing only carbon and hydrogen. 1.9
inorganic compound any compound that does not contain carbon. 1.9
organic compound A molecular compound of carbon other than carbonates and cyanides and carbon dioxide. 1.9
chemical property Observed when a substance undergoes a transformation into one or more new substances. 2.2
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
atomic mass unit 1/12 the mass of a C-12 atom. 2.3
atomic mass Determined by the mass of protons and neutrons in the atom. 2.3
Avogadro's number The number of atoms in 12 g of carbon-12. 6.022 x 1023. 2.3
law of definite proportions Different samples of a pure compound always contain the same elements in the same proportions by mass. 2.3
mole A collection of objects that contains Avogadro's number of objects. (6.02 x 1023). 2.3
atomic orbital A region in space where electrons on an atom can be found. 2.5
electron orbit The path of the electron in its motion around the nucleus of Bohr's hydrogen atom. 2.5
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
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
chemical group A family on elements in the periodic table that have similar electron configurations. 2.6
electron configuration The arrangement of electrons in atomic orbitals; for example, 1s2 2s2 2p3.     2.6
period A horizontal row of elements in the periodic table. 2.6
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
valence electrons The outermost electrons of an atom. These electrons are involved in chemical bonding of atoms. 2.7
binary compound Chemical compound composed of only two elements. 2.8
covalent bond A bond between two atoms formed by the sharing of a pair of electrons. 2.8
halogens Elements that constitute Group VIIB of the Periodic Table of Elements: fluorine, chlorine, bromine, iodine and astatine. 2.8
ionic bond An attraction between oppositely charged ions. 2.8
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
fusion A nuclear reaction in which nuclei combine to form more massive nuclei with the simultaneous release of energy. 2.9
isotope Atoms of the same element but different atomic masses due to different number of neutrons. 2.9
nuclear force That force exerted by subatomic particles that is responsible for form, shape, and motion of particles in the atom. 2.9
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
chemical reaction A change in the arrangement of atoms or molecules to yield substances of different composition and properties. 3.1
chemical change The change of substances into other substances, with different chemical composition, through a reorganization of the atoms; a chemical reaction. 3.1
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
precipitate An insoluble solid formed in a liquid solution as a result of some chemical reactions. 3.1
saturated solution The maximum amount of solution that can be dissolved at a given temperature and pressure. 3.1
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
acid base indicator A dye that has a certain color in an acid solution and a different color in a base solution. 3.2
chemical test Procedure or chemical reaction used to identify a substance. 3.2
anion A negatively charged ion. 3.3
cation A positively charged ion. 3.3
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
molecular compound Two or more atoms bond together by sharing electrons (covalent bond). 3.3
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
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
decomposition. A chemical reaction in which a single compounds reacts to yield two or more products. 3.4
double-displacement reaction. A chemical reaction in which two ionic compounds exchange cations to produce two new compounds. 3.4
single-displacement reaction. A chemical reaction in which an element replaces another element in a compound. 3.4
synthesis reaction. When two or more substances combine to form a new compound. 3.4
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
temperature The measure of average kinetic energy of all the particles of material. 3.5
catalyst A substance that increases the rate of a chemical reaction, without being changed itself in the reaction. 3.6
surface area Changing the nature of the reactants into smaller particles increases the surface exposed to react. 3.6
acid A substance that produces hydrogen ions in water, or is a proton donor. 3.7
base A substance that releases hydroxide ions (-OH) in water or is a proton acceptor. 3.7
neutralization The process of an acid and base reacting to form water and salt. 3.7
pH A quantity used to represent the acidity of a solution based on the concentration of hydrogen ions. 3.7
reduction A process in which the substance under consideration gains electron(s). 3.8