25 terms

Chapter 2; part 1

a substance that increases the hydrogen ion concentration in a solution
aqueous solution
a solution in which water is a solvent
the smallest unit of matter that retains the properties of and element
atomic number
the number of protons in each atom of a particular element
a substance that decreases the hydrogen ion (H+) concentration in a solution
a chemical substance that resist changes in pH by accepting hydrogen ions from or donation hydrogen ions to solutions
chemical bond
an attraction between two atoms resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms; the bonded atoms gain complete outer electron shells
chemical reactions
a process leading to chemical changes in matter, involving the making and/or breaking of chemical bonds
the attraction between molecules of the same kind
a substance containing two or more elements in a fixed ratio; for example, tale salt (NaCl) consists of one atom of the element sodium (Na) for every atom of chlorine (Cl)
covalent bond
an attraction between atoms that share one or more pairs of outer-shell electrons; symbolized by a single line between the atoms
a subatonic particle with a single unit of negative electrical charge; one or more electrons move around the nucleus of an atom
a substance that cannot be broken down to other substances by chemical means; scientists recognize 92 chemical elements occuring in nature
evaporative cooling
the property of a liquid whereby the surface becomes cooler during evaporation, owing to a loss of highly kinetic molecules to the gaseous state
the amount of energy associated with the movement of the atoms and molecules in a body of matter; heat is energy in its most random form
hydrogen bonds
a type of weak chemical bond formed when the partially positive hydrogen atom participating in a polar covalent bond in one molecule is attracted to the partially negative atom participating in a polar covalent bond in another molecule (or in another part of the same macromolecule)
ionic bond
an attraction between two ions with opposite electrical charges; the electrical attraction of the opposite charges holds the ions together
a variant form of an atom, isotopes of an element have the same number of protons and electrons but different numbers of neutrons
mass number
the sum of the number of protons and neutrons in an atom's nucleus
a measure of the amount of material in an object
anything that occupies space and has mass
a group of two or more atoms held together by covalent bonds
an electrically charged neutral particle (a particle having no electrical charge), found in the nucleus of an atom
pH scale
a measure of the relative acidity of a solution, ranging in value from 0 (most acidic) to 14 (most basic); pH stands for potential hydrogen and refers to the concentration of hydrogen ions (H+)
polar molecule
a molecule containing polar and covalent bonds (having opposite charges on opposite ends)