chemistry final - vocab

anion

an atom or group of atoms with a negative charge

cation

an atom or group of atoms with a positive charge

ion

an atom or group of atoms that has a positive or negative charge

monatomic ion

a single atom with a positive or negative charge as a result of losing or gaining valence electrons

polyatomic ions

a tightly bound group of atoms that behaves as a unit and carries a charge

molecule

a neutral chemically bonded group of atoms that act as a unit

binary compound

a compound composed of two elements

ionic compound

a compound composed of positive and negative ions

molecular compound

a compound composed of molecules

ternary compound

a compound containing atoms of three different elements, usually containing at least one polyatomic ion

chemical formula

shows the number and type of atoms present in the smallest representative unit of a substance

molecular formula

a neutral chemically bonded group of atoms that act as a unit

formula unit

the lowest whole-number ratio of ions in an ionic compound

law of definite proportions

in any sample of a chemical compound, the elements are always combined in the same proportion by mass

law of multiple proportions

whenever two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers

activity series of metals

a table listing metals in order of decreasing activity

catalyst

a substance that increases the rate of reaction by lowering the activation energy barrier

coefficient

a small whole number that appears in front of a formula in a balanced equation

spectator ion

an ion that is not directly involved in a chemical equation

combination reaction

a chemical change in which two or more substances react to form a single new substance

combustion reaction

a chemical change in which oxygen reacts with another substance, often producing energy in the form of heat and light

decomposition reaction

a chemical change in which a single compound is broken down into two or more simpler products

double replacement reaction

a chemical change that involves an exchange of positive ions between two compounds

single replacement reaction

a chemical change in which one element replaces a second element in a compound

balanced equation

a chemical equation in which mass is conserved; each side of the equation has the same number of atoms of each element

chemical equation

an expression representing a chemical reaction

complete ionic equation

an equation for a reaction in solution showing all strong electrolytes as ions

net ionic equation

an equation for a reaction in solution showing only those particles that are directly involved in the chemical change

skeleton equation

a chemical equation that does not indicate the relative amounts of reactants and products

avogadro’s number

the number of representative particles contained in one mole of a substance

empirical formula

the formula of the lowest whole number ratio of elements in a compound

gram atomic mass

the mass, in grams, of one mole of atoms in a monatomic element

gram formula mass

the mass of one mole of an ionic compound

gram molecular mass

the mass, in grams, of one mole of a molecular compound

molar mass

a general expression used to refer to the mass of a mole of any substance unless a more specific term is needed to avoid confusion

molar volume

the volume occupied by 1 mole of a gas at standard temperature and pressure

mole

the amount of a substance that contains 6.02 x 10^23 representative particles of that substance

percent composition

the percent by mass of each element in a compound

representative particle

the smallest unit into which a substance can be broken down without a change in composition

standard temperature and pressure

the condition under which the volume of a gas is usually measured

amplitude

the height of a wave from the origin to the crest

atomic emission spectrum

the pattern of frequencies obtained by passing light emitted by atoms of an element in the gaseous state through a prism

atomic orbitals

a region in the space around the nucleus of an atom where there is a high probability of finding an electron

aufbau’s principle

electrons enter orbitals of lowest energy first

debroglie’s equation

an equation that describes the wavelength of a moving particle; it predicts that all matter exhibits wavelike motions

electromagnetic radiation

a series of energy waves that travel in a vacuum at 3.0 x 10^10 cm/s

electron configuration

the arrangement of electrons around the nucleus of an atom in its ground state

energy level

a region around the nucleus of an atom where an electron is likely to be moving

frequency

the number of wave cycles that pass a given point per unit of time

ground state

the lowest energy level occupied by an electron when an atom is in its most stable energy state

heisenberg’s uncertainty principle

it is impossible to know both the velocity and the position of a particle at the same time

hertz (Hz)

the SI unit of frequency, equal to one cycle per second

hund’s rule

when electrons occupy orbitals of equal energy, one electron enters each orbital until all orbitals contain one electron with their spins parallel

pauli’s exclusion principle

no more than two electrons can occupy an atomic orbital

photoelectric effect

electrons are ejected by certain metals when they absorb light with a frequency above the threshold frequency

photon

a quantum of light; a discrete bundle of electromagnetic energy that behaves as a particle

planck’s constant

a number used to calculate the radiant energy absorbed or emitted by a body on the frequency of radiation

quantum

the amount of energy needed to move an electron from its present energy level to the next higher one

quantum mechanical model

the modern description, primarily mathematically, of the behavior of electrons in atoms

spectrum

range of wavelengths of electromagnetic radiation

wavelength

the distance between two adjacent crests of a wave

atomic radius

one-half the distance between the nuclei in a molecule consisting of identical atoms

electronegativity

the tendency for an atom to attract electrons to itself when it is chemically bonded with another element

inner transition metals

an element in the lanthanide and actinide series characterized by addition of electrons to “f” orbitals

ionized energy

the energy required to remove an electron from a gaseous atom

noble gases

any member of a group of gaseous elements in Group O of the periodic table

representative element

group A elements on the periodic table; together, these elements, which have only partially filled outermost “s” and “p” sublevels

transition metal

group B element characterized by addition of electrons to “d” suborbitals

calorie

the quantity of heat that raises the temperature of 1 gram of pure water 1 C

calorimeter

a device for measuring heat changes

calorimetry

the measurement of heat changes for physical and chemical processes

chemical potential energy

energy stored within the structural units of chemical substances

endothermic process

a heat-absorbing process

energy

the capacity for doing work

enthalpy

the heat content of a system at constant pressure

exothermic process

a heat-dissipating (releasing) process

heat

the energy that is transferred from one body to another because of a temperature difference

heat capacity

the quantity of heat required to change an object’s temperature by 1 C

heat of combustion

the heat released during a chemical reaction in which one mole of a substance is completely burned

heat of reaction

the heat released or absorbed during a chemical reaction

hess’s law of heat summation

in going from a particular set of reactants to a particular set of products, the enthalpy change is the same whether the reaction takes place in one step or in a series of steps

joule

the SI unit of energy; 4.184 J = 1 calorie

law of conservation of energy

energy is neither created nor destroyed in an ordinary chemical or physical process

molar heat of condensation

the heat, in joules or calories, released by 1 mole of a substance as it changes from a vapor to a liquid at the liquid’s boiling point

molar heat of fusion

the energy, in kilojoules, required to melt 1 mole of a solid

molar heat of solidification

the heat, in joules or calories, released by 1 mole of a substance as it changes from a liquid to a solid at the solid’s melting point

molar heat of solution

the heat, in joules or calories, released or absorbed by 1 mole of a substance as it dissolves in water to produce 1 liter of a 1 molar substance

molar heat of vaporization

the energy, in kilojoules, required to vaporize 1 mole of liquid

specific heat

the quantity of heat, in joules or calories, required to raise the temperature of 1 gram of a substance 1 C

standard heat of formation

the change in enthalpy for a reaction in which one mole of a compound is formed from its constituent elements

surroundings

the remainder of the universe that is outside the system

thermochemical equation

a chemical equation that includes the amount of heat produced or absorbed during the reaction

thermochemistry

the study of heat changes in chemical reactions

universe

the totality of all existing things

avogadro’s hypothesis

equal volumes of gases at the same temperature and pressure contain equal numbers of particles

boyle’s law

P1V1 = P2V2

charles' law

V1/T1 = V2/T2

combined gas law

P1V1/T1 = P2V2/T2

dalton’s law of partial pressure

Ptotal = P1 + P2 + P3

diffusion

the tendency of molecules to move toward areas of lower concentration until the concentration is uniform throughout