| A | B |
|---|
| acid | a chemical that contributes hydrogen ions, H+ to a solution |
| acid precipitation | rain, snow or fog that has a pH lower than 5.6 |
| alpha particles | a partially charged particle emitted from the nucleus of an atom during radioactive decay; also called a helium nucleus |
| atom | the smallest particle of an element that can exist alone or in combination with other atoms |
| atomic mass | defined as the mass of l/12 of a carbon - 12 aton (6 protons and 6 neutrons in the nucleus plus 6 electrons outside the nucleus) |
| atomic number | the number of protons that an atom contains |
| Archimedes principle | a principle that states that the force exerted on an object in a liquid is equal to the weight of the fluid displaced by the object |
| Avogardo's number | the number of atoms in the atomic mass of an element, or the number of molecules in the formula mass of a compound when these masses are expressed in grams |
| base | a chemical that contributes hydroxyl ions, OH-, to a solution |
| beta particles | a negatively charged particle (an electron) emitted from the nucleus of an atom during radioactive decay |
| binary compounds | a covalent compound that consists of only two types of elements |
| boiling point | xxxxx |
| Boyle's Law | pressure and volume are inversely related |
| brittleness | a measure of a material's tendency to shatter upon impact |
| buoyancy | a measure of the upward force a fluid exerts on an object |
| Charles' Law | the volume of a gas increases with increasing temperature if pressure is held constant |
| chemical change | a change in a substance that involves the breaking and reforming of chemical bonds to make a new substance or substances |
| chemical formula | a representation of a compound that includes the symbols and numbers of atoms in the compound |
| chemical symbol | an abbreviation that represents the name of an element; used in chemical formulas |
| combustion reaction | a reaction in which a substance combines with oxygen, releasing large amounts of energy in the form of heat and light |
| compound | substances made of two or more elements that cannot be separated by physical means |
| condensation | the process by which a substance in its gaseous state loses energy and enters its liquid state, one phase in the water cycle |
| covalent bond | shared electrons between 2 atoms |
| density | a property that describes the relationship btw. mass and volume |
| diatomic molecules | a molecule that has only two atoms of the same element |
| dissociation | xxxxxxxxxxxxxxxxx |
| double - displacement | a reaction in which ions from two compounds in a solution exchange places to produce two new compounds |
| elasticity | a msaures of a solid's ability to stretch and then return to its original shape and size |
| electron | a subatomic particle in an atom that is negatively charged and occupes the energy levels in an atom; electrons are involved in chemical bonds and reactions |
| electronegativity | the attraction an atom has for the shared pair of electrons in a chemical bond |
| electromagnetic force | the force that exists between electric charges; often described as electrical force or magnetic force depending on how charges interact |
| element | substances that contain only one kind of matter |
| energy levels | a region around the nucleus of an atom where electrons are most likely to be found; only a certain number of electrons can be found in each energy level of an atom |
| equilibrium | in physics--occurs when the forces of an object are balanced (in chemistry- the state in which the solute in a solution is dissolving and coming out of the solution at the same rate) |
| evaporation | the process by which a substance in its liquid state gains energy and enters its gaseous state; one phase of the water cycle |
| freezing point | xxxxxxxxxxxxx |
| fluid | xxxx |
| formula mass | determined by adding up the atomic mass units of all the atoms in the compound; a way to compare the masses of molecules of different compounds |
| gamma rays | a photo emitted spontaneously by a radioactive substance |
| group of elements | elements that exhibit similar chemical properties; arranged in columns on the periodic table |
| half-life | the length of time it takes for half an amount of radioactive substance to undergo radioactive decay |
| hardness | measures a solids resistance to scratching |
| ions | an atom that has an electrical charge |
| ionic bonds | a type of chemical bond between atoms that gained or lost electrons; a bond between ions |
| ionization | xxxxxxxxxx |
| isotopes | forms of the same element that have different numbers of neutrons and different mass numbers |
| law of conservation of mass | states that the total mass of products of a reaction is equal to the toal mass of reactants |
| malleability | a solid's ability to be pounded into thin sheets |
| mass | a measure of the inertia of an object; the amount of matter an object has |
| matter | anything that has mass and takes up space |
| meniscus | the dip when reading a liquid in a graduated cylinder |
| metal bond | xxxx |
| mixture | substance that contains more than one kind of matter |
| mole | one set of 6.02 x 10 to the 23rd power atoms or molecules |
| molecule | the smallest particle of a compound that retains the properties of the compound |
| monatomic molcecules (monoatomic ions) | ions that contain only one type of atom |
| neutral | 1-a solution that has a pH of 7, meaning it has equal numbers of H+ and OH- or acidic and basic, ions (2) when one proton is paired with one electron |
| neutron | an uncharged particle found in the nucleus of an atom |
| non-electrolyte | chemicals that do not form ions when they are dissolved in a solution |
| nucleus | the center core of an atom that contains protons and neutrons |
| octet rule | states that atoms form bonds with other atoms by sharing or transferring them to complete their octet and become stable |
| oxidation numbers | indicates how many electrons are lost or gained (or shared) when bonding occurs |
| pH | the exact concentrations of H+ ions and OH- ions in a solution |
| phase change diagrams | xxxxxxxxxxxx |
| physical change | change in the physical properties of a substance |
| polyatomic ions | ions that contain more than one type of atom |
| polymers | a large molecule that is composed of repeating smaller molecules called subunits or monomers |
| proton | a subatomic particle identical with the nucleus of the hydrogen atom; found with neutrons in all atomic nuclei; carries a positive charge |
| products | substances that are produced in a chemical reaction from reactants |
| radioactivity | a term to describe an atomic state when the nucleus is emitting radiation in the form of particles and energy until it becomes more stable |
| radioactive decay | xxxxxxxx |
| strong nuclear force | the force that holds protons together when they are very close together (only 10 to the -15th apart) |
| solvent | the component of a solution that dissolves the solute and is present in the greatest amount |
| single displacement reaction | a reaction in whcih on element replaces a similar element in a compound |
| solution | a mixture of two or more substances that is homogenous at the molecular level; a solution consists of a solute and a solvent |
| reactants | a substance that enters into and is altered in the course of a chemical reaction |
| sublimation | xxxxxxxxxx |
| substance | a mixture that cannot be separated into different kinds of matter using physcial means |
| suspension | a type of mixture in which the particles (atoms or molecules) are larger than 1,000 nanometers in diameter |
| synthesis reaction | xxxxx |
| valence electrons | the electrons in an atom that are involved in the formation of chemical bonds |
| viscosity | a measure of a materials resistance to flow |
