Chemistry Semester 2 Final Key Terms

greenhouse effect

a warming effect exerted by certain molecules in the earth’s atmosphere

exothermic

refers to a reaction in which energy flows out of the system

state function

a property that is independent of its pathway

potential energy

stored energy

thermodynamics

a study of energy and its interactions

windmill

a type of renewable resource

petroleum

liquid portion known as crude oil; thick dark liquid composed mostly of hydrocarbon compounds

endothermic

delta H is positive in this process

fossil fuel

nonrenewable resource

kinetic energy

dependent on the mass of the object and the square of its velocity

joule

unit of measurement for energy

energy

the capacity to do work or to cause the flow of heat

temperature

measure of the random motions of the components of a substance

mechanical energy

the sum of the kinetic and potential energy of all components of an object

fossil fuel

a fuel that consists of carbon based molecules derived from decomposition of once-living organisms

heat

energy transferred between two objects because of a temperature difference between them

endothermic

refers to a reaction in which energy flows into the system

kinetic energy

has the formula of 1/2mv2

specific heat quantity

the quantity of energy required to heat one gram of water by one Celsius degree

calorie

unit of measurement for energy

system

the part of the universe on which attention is to be focused

calorie

4.184 J

calorimeter

device used to determine the heat associated with a chemical reaction

law of conservation of energy

states that the energy of the universe is constant; energy can be converted from one form to another but can neither be created nor destroyed

coal

type of fossil fuel

core electron

an electron that is not in the outermost principal quantum level

frequency

the number of waves/cycles per second that pass a given point in space

nonmetals

an element that does not exhibit metallic characteristics

nonmetals

located to the right of the stair-step ladder

ionization energy

the quantity of energy required to remove an electron from a gaseous atom or ion

electron configuration

electron arrangement

metalloids

an element that has both metallic and nonmetallic properties

wavelength

the distance between two consecutive peaks or troughs in a wave

electromagnetic radiation

radiant energy that exhibits wave-like behavior and travels through space at the speed of light in a vacuum

metalloids

located along the stair-step ladder

valence electrons

the electrons in the outermost occupied principal quantum level of an atom

orbital

a representation of the space occupied by an electron in an atom; the probability distribution for the electron

nonmetal

accepts electrons from a metal

main group elements

elements in the groups labeled 1-8

quantized energy level

main energy level of an electron; the discrete energy level

orbital diagram

also known as box diagrams

main group elements

also known as representative elements

proton

a “particle” of electromagnetic radiation

metals

located to the left of the stair-step ladder

core electron

an inner electron in an atom

metal

an element that gives up electrons relatively easily and is typically lustrous, malleable, and a good conductor of heat and electricity

covalent bond

a bond in which the electrons are shared equally

ionic bonding

the attraction between oppositely charged ions

molecular structure

the three dimensional arrangement of atoms in a molecule

bond energy

the energy required to break a given chemical bond

octet rule

the observation that atoms of nonmetals form the most stable molecules when they are surrounded by 8 electrons

resonance

a condition occurring when more than one valid lewis structure can be written for a particular molecule

electronegativity

the tendency of an atom in a molecule to attract shared electrons to itself

double bond

a bond in which two atoms share two pairs of electrons

lewis structure

a diagram of a molecule showing how the valence electrons are arranged among the atoms in a molecule

covalent bonding

a type of bonding in which atoms share electrons

ionic compound

a compound that results when a metal reacts with a nonmetal to form cations and anions

bonding pair

an electron pair found in the space between two atoms

lone pair

an electron pair that is localized on a given atom; an electron pair not involved in bonding

dipole moment

a property of a molecule whereby the charge distribution can be represented by a center of positive charge and a center of negative charge

polar covalent bond

a bond in which the electrons are not shared equally because one atom attracts them more strongly than the other

bond

the force that holds two atoms together in a compound

ideal gas law

PV = nRT

partial pressures

the independent pressures exerted by different gases in a mixture

pascal

SI unit for pressure

standard temperature and pressure

the condition 0oC and 1 atmosphere of pressure

kinetic molecular theory

a model that assumes that an ideal gas is composed of tiny particles in constant motion

boyles law

the volume of a given sample of gas at constant temperature varies inversely with pressure

charles law

the volume of a given sample of gas at constant pressure is directly proportional to the temperature in kelvins

charles law

V1/T1 = V2/T2

torr

another name for mm Hg

barometer

a device for measuring atmospheric pressure

standard atmosphere

volume of one mole of an ideal gas; equal to 22.42 liters at standard temperature and pressures

universal gas constant

0.08206 atm/mol

pascal

equal to one Newton per square meter

ideal gas

a hypothetical gas that exactly obeys the ideal gas law

daltons law of partial pressures

for a mixture of gases in a container, the total pressure exerted is the sum of the pressures that each gas would exert if it were alone

universal gas constant

the combined proportionality constant in the ideal gas law

boyles law

P1V1 = P2V2

ideal gas law

an equation relating the properties of an ideal gas; expresses behavior closely approached by real gases at high temperature and/or low pressure

avogrados law

equal volume of gases at the same temperature and pressures contains the same number of particles

mm Hg

equivalent to one torr

psi

unit for pressure used in engineering sciences

dipole dipole attraction

type of intermolecular force

alloy

substance that contains a mixture of elements and has metallic properties

interstitial alloy

type of alloy

vaporization

the change in state that occurs when a liquid evaporates to form a gas

molar heat of fusion

the energy required to melt 1 mol of a solid

atomic solid

a solid that contains atoms an the lattice points

vapor pressure

the pressure of the vapor over a liquid at equilibrium in a closed container

dipole dipole attraction

the attractive force resulting when polar molecules line up such that the positive and negative ends are close to each other

intramolecular forces

interactions that occur within a given molecule

hydrogen bonding

unusually strong dipole-dipole attractions that occur among molecules in which hydrogen is bonded to a highly electronegative atom

vaporization

evaporation

electrolyte

a solid containing cations and anions that dissolves in water to give a solution containing the separated ions, which are mobile and thus free to conduct an electric current

heat of vaporization

the energy required to vaporize 1 mol of a liquid

condensation

the process by which vapor molecules reform a liquid

heating cooling curve

a plot of temperature versus time for a substance, where energy is added at a constant rate

crystalline solid

a solid characterized by the regular arrangement of its components

london dispersion force

the relatively weak forces, which exist among noble gas atoms and non polar molecules, that involve an accidental dipole that induces a momentary dipole in a neighbor