Term | Definition |
Chemisrty | the science that deals with the materials of the universe and the changes that these materials undergo. |
Scientific Method | systematic process for studying nature that involves observations, hypotheses, and experiments |
Measurments | a quantitative observation |
Natural Law | statement that summarizes generally observed behavior |
Matter | the "stuff" of which the universe is compoosed |
Atom | fundamental unit of which elements are made |
Compounds | substances made by bonding atoms together in specific ways |
Molecule | a collection of atoms bonded together that behave as a unit |
Elements | substances containing only one type of atom |
Solid | substance with fixed shape and volume |
Liquid | substance with definite volume that takes the shape of its container |
Gas | substance with no definite shape or volume |
Physical Property | characteristic of a substance that can change without the substance's becoming different substance |
Chemical Property | characteristics that describes the ability of a substance to change to a different substance |
Physical Change | change that does not affect the composition of a substance |
Chemical Change | change in which a substance becomes a different substance |
Mixture | a substance with variable compositions |
Alloy | a mixture of elements that has metallic properties |
Pure Substance | either a pure element or a compound |
Homogeneous Mixture | a mixture that is the same throughout |
Solution | a homogeneous mixture |
Heterogeneous Mixture | a mixture containing regions with differing properties |
Distillation | a separation process that depends on the different boiling points of the subatance |
Filtration | separation of a solid from a liquid by using filter paper |
Element Sybmols | code for a chemical element |
Law of Constant Composition | a given compound always contains elements in exactly the same proportion by mass |
Chemical Formula | a set of chemical symbols showing the elements present in a compound and their relative proportions, and in some cases the structure of the compound |
Electron | a negatively charges subatomic particle |
Nuclear atom | a modern concept of the atom as having a dense center of positive charge surrounded by moving electrons |
Nucleus | the relatively small, dense center of positive charge in an atom |
Protron | a positively charged subatomic particle located in the atomic nucleus |
Neutron | a subatomic particle with no charge located in the atomic nucleus |
Isotopes | atoms with the same number of protons but different numbers of neutrons |
Atomic Number | the number of protons in the nucleus of a given atom |
Mass Number | the total number of protons and neutrons in the nucleus of a given atom |
Periodic Table | a table of the chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure appear in vertical columns. |
Groups | a vertical column of elements on the periodic table |
Diatomic Molecule | a molecule composed of two atoms |
Ion | an atom or group of atoms that has a positive or negative charge |
Cation | a positively charged ion |
Anion | a negatively charges ion |
Ionic Compound | a compound that results when a metal reacts with a nonmetal to form cations and anions |
Binary Ionic Compound | a two- element compound consisting of a cation and an anion |
Polyatomic Ions | an ion consisting of two or more atoms bound together |
Oxyanion | a polyatomic ion containing at least one oxygen atom and one or more atoms of at least one other element |
Acid | a substance that produces hydrogen ions in solutions |
Unit | the part of the measurement telling us the scale being used |
Volume | the amount of three- dimensional space occupied by a substance |
Mass | the quantity of matter in an object |
Significant Figures | the certain digits and the first uncertain digit of a measurment |
Conversion Factor | a ratio used to convert from one unit to another |
Dimensional Analysis | the process of using conversion factors to change from one unit to another |
Density | the mass of a substance per a given volume of that substance |
Specific Gravily | the ratio of the density of given liquid to the density of water at 4 degrees Celsius |
Atomic Mass Unit (AMU) | a small unit of mass equal to 1.66 X 10-24 grams |
Average Atomic Mass | the weighed average of the masses of all the isotopes of an element |
Mole | the number equal to the number of carbon atoms in exactly 12 grams of pure 12C: Avogadro's number. |
Molar Mass | the mass in grams of 1 mole of the substance |
Mass Percent | Percent= Part/Whole X 100% |
Empirical Formula | the formula of a compound expressing the smallest whole- number ratio of atoms in the compound |
Molecular Formula | the actual formula of a compound giving the types of atoms and the numbers of each type of atom |
Chemical Reaction | one or more substances are changed into one or more new substances by reorganization of component atoms |
Chemical Equation | a representation of a chemical reaction using the formulas of the starting substances that react and the new substances that are formed |
Reactant | the starting substance of a chemical reaction, shown to the left of the reaction arrow |
Product | the new substance formed by the chemical reactions, shown on the right of the reaction arrow |
Coefficient | the number written in front of the chemical formulas in balanced chemical reactions |
Precipitation | the formation of a solid in a chemical reaction |
Precipitate | the solid that forms in a precipitation reaction |
Precipitation Reaction | a reaction in which a solid forms and seperates from the solution |
Strong Electrolyte | a substance that dissolves in water by dissociating completely into ions |
Soluble Solid | a solid that readily dissolves in water |
Insoluble Solid | a solid that dissolves to such a small degree that it is not detectable to the naked eye |
Strong Acid | an acid that completely dissociates to produce H+ ions in solution |
Strong Base | a base that completely dissociates tp produce OH- ions in solution |
Salt | an ionic compound |
Oxidation- Reduction Reaction | a chemical reaction involving the transfer of electrons |
Combustion Reaction | a chemical reaction involving oxygen as one of the reactants that produces enough heat so that a flame results |
Synthesis Reaction | a chemical reaction in which a compound is formed from simpler materials |
Decomposition | a chemical reaction in which a compound is broken down into simpler compounds, or to the component elemenets |
Molecular Equation | a chemical equation showing the complete forms of all reactants and products |
Complete Ionic Equation | a chemical equation for the reaction in solution representing all strong electrolytes as ions |
Spectator Ion | an ion present in solution that does not participate in a reaction |
Net Ionic Equation | a chemical equation for the reaction in solution showing only those components that are directly involved in the reaction |