Theory -- a broad generalization that explains a body of facts or phenomena

Hypothesis -- a testable statement

Mass -- a measure of the quantity of matter

Weight -- a measure of the gravitational pull on matter

Accuracy -- the closeness of measurements to the correct or accepted value of the quantity measured

Precision -- the closeness of a set of measurements of the same quantity made in the same way

Significant figures -- consists of all the digits known with certainty plus one final digit, which is somewhat uncertain or is estimated

Scientific notation -- numbers are written in the form M x 10ⁿ, where the factor M is a number greater than or equal to 1 but less than 10 and is a whole number

Law of Conservation of Mass -- states that mass is neither created nor destroyed during ordinary chemical reactions or physical changes

Law of Definite Proportions -- the fact that a chemical compound contains the same elements in exactly the same proportions by mass regardless of the size of the sample or the source of the compound

Law of Multiple Proportions -- if two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small whole numbers

Atom -- the smallest particle of an element that retains the chemical properties of that element

Nuclear forces -- the short-ranged proton-neutron, proton-proton, and neutron-neutron forces that hold particles together

Atomic number -- the number of protons of each atom of that element

Isotopes -- atoms of the same element that have different masses

Mass number -- the total number of protons and neutrons that make up the nucleus of an isotope

Nuclide -- general term for a specific isotope of an element

Atomic mass unit -- 1/12 the mass of a carbon-12 atom

Average atomic mass -- the weighted average of the atomic masses of the naturally occurring isotopes of an element

Mole -- SI unit for amount of substance

Avogadro’s number -- 6.022 x 10²³

Molar mass -- the mass of one mole of pure substance

Democritus -- 400 BC; called nature's basic particle an atom

John Dalton -- 1808; an English school teacher who proposed an explanation for the Law of Conservation of Mass, Law of Definite Proportions, and the Law of Multiple Proportions

Joseph John Thompson -- 1897; English physicist who concluded that all cathode rays are composed of identical negatively charged particles, called electrons and came up with the "plum pudding" model

Robert A. Millikan -- 1909; American physicist who measured the charge of the electron

Ernest Rutherford -- 1911; New Zealand; discovered the nucleus

Dalton's Atomic Theory -- All matter is composed of extremely small particles called atoms

Dalton's Atomic Theory -- Atoms of a given element are identical in size, mass, and other properties; atoms of different elements differ in size, mass, and other properties

Dalton's Atomic Theory -- Atoms cannot be subdivided, created, or destroyed

Dalton's Atomic Theory -- Atoms of different elements combine in simple whole number ratios to form chemical compounds

Dalton's Atomic Theory -- In chemical reactions, atoms are combined, separated, or rearranged

Electromagnetic radiation -- a form of energy that exhibits wavelike behavior as it travels through space

Electromagnetic spectrum -- made up of all the forms of electromagnetic radiation

Wavelength -- the distance between corresponding points on adjacent waves

Frequency -- defined as the number of waves that pass a given point in a specific time, usually one second

Photoelectric -- effect the emission of electrons from a metal when light shines on the metal

Quantum -- the minimum quantity of energy that can be gained or lost by an atom

Photon -- a particle of electromagnetic radiation having zero mass and carrying a quantum of energy

Ground state -- the lowest energy state of an atom

Excited state -- a state in which an atom has a higher potential energy than it has in its ground state

Line-emission spectrum --a diagram or graph that indicates the degree to which a substance emits radiant energy with respect to wavelength

Continuous spectrum -- the emission of continuous range of frequencies of electromagnetic radiation

Diffraction -- the bending of a wave as it passes by the edge of an object or through a small opening

Interference -- when waves overlap

Heisenberg uncertainty principle -- states that it is impossible to determine simultaneously both the position and velocity of an electron or any other particle

Quantum theory -- describes mathematically the wave properties of electrons and other very small particles

Orbital -- a 3-D region around the nucleus that indicates the probable location of an electron

Electron -- configuration the arrangement of electrons in an atom

Ababa principle -- An electron occupies the lowest energy orbital that can receive it

Pauli Exclusion Principal -- No two electrons in the same atom

Hund's Rule -- orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second

Noble gases -- the Group 18 elements

Noble-gas configuration -- an outer main energy level occupied by 8 electrons

Mendeleev -- he created a table in which elements with similar properties were grouped together

Moseley -- arranged the periodic table where atomic numbers were the basis of the order

Lewis structures -- formulas in which atomic symbols represent nuclei and inters hell electrons

VSEPR -- "valence-shell, electron-pair repulsion"; states that repulsion between the sets of valence-level electrons surrounding an atom causes these sets to be oriented as far as possible

Chemical bond -- mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together

Ionic bonding -- chemical bonding that results from the electrical attraction between cations and anions

Covalent bonding -- chemical bonding that results from the sharing of electron pairs between two atoms

Nonpolar-covalent bond -- a covalent bond in which the bonding electrons are shared equally by the bonded atoms, resulting in a balanced distribution of electrical charge

Polar -- having an uneven distribution of charge

Polar-covalent bond -- the bonded atoms have an unequal attraction for the shared electrons

Molecular compound -- a chemical compound whose simplest units are molecules

Molecular formula -- shows the types and numbers of atoms combined in a single molecule of a molecular composition

Chemical formula -- indicates the relative numbers of atoms of each kind in a chemical compound by using atomic symbols and numerical subscripts

Bond energy -- the energy required to break a bond

Evaporation -- the process by which particles escape from the surface of a no boiling liquid and enter the gas state

Vaporization -- the process by which a liquid or a solid changes to a gas

Capillary action -- the attraction of the surface of a liquid to the surface of a solid

Boiling point -- the temperature at which the equilibrium vapor pressure of the liquid equals the atmospheric pressure

Sublimation -- the change of state from a solid to a gas

Deposition -- the change of state from a gas to a solid

Crystalline solids -- a substance in which the particles are arranged in an orderly pattern

Amorphous solids -- a substance in which the particles are arranged in a random pattern

Effusion -- when gas escapes through a very small hole in a container

Diffusion -- when gas oozes from one edge to another

Molarity -- the number of moles of solute in one liter of solution

Molality -- the concentration of a solution expressed in moles of solute per kilogram of solvent

Soluble -- capable of being dissolved

Solution -- a homogeneous mixture of two or more substances in a single phase

Solute -- the substance dissolving into the solution

Solvent -- the dissolving medium in a solution

Suspension -- the particles in a solvent are so large that they settle out unless the mixture is constantly stirred

Colloids -- particles that are intermediate in size between a solution and a suspension

Electrolyte -- a substance that dissolves in water to give a solution an electric current

Nonelectrolyte -- a substance that dissolves in water that doesn't conduct an electric current

Saturated solution -- a solution that contains the maximum amount of dissolved solute

Unsaturated solution -- a solution that contains less solute than a saturated solution under the existing conditions

Supersaturated solution -- a solution that contains more dissolved solute than a saturated solution contains under the same conditions

Hydration -- the solution process with water as the solvent

Immiscible liquids -- that are not soluble in each other

Miscible liquids -- that dissolve freely in one another in any proportion

Effervescence -- the rapid escape of a gas from a liquid in which it is dissolved

Dissociation -- the separation of ions that occurs when an ionic compound dissolves

Spectator ions -- ions that do not take part in a chemical reaction and are found in solution both before and after the reaction

Effects of pressure on gas solubility -- if the pressure of a gas increases, the gas solubility increases

Effects of temperature on solubility -- if the temperature of a gas increases, the solubility of that gas decreases

Osmosis -- the movement of solvent through a semipermiable membrane

Colligative properties -- properties that depend on the concentration of solute particles but not their identity

Binary acid -- an acid that contains only two different elements, one being hydrogen and the other being one of the more electronegative elements

Oxyacid -- an acid that is a compound of hydrogen, oxygen, and a third element, usually nonmetal

Arrhenius acid -- give off H+ ions or hydronium ions, H₃O+

Arrhenius base -- give off OH- ions

Titration -- using a known concentration to find an unknown concentration

Monoprotic -- one hydrogen

Diprotic -- two hydrogens

Polyprotic -- more than two hydrogens

Amphoteric -- any species that can react as either an acid or a base

Activation energy -- the amount of energy needed to start a reaction

How to make a reaction go faster

- Surface area

-increase temperature

-concentration

-catalysts

How to make a substance dissolve faster

-decrease the surface area

-stirring or shaking the solvent

-increasing the temperature

Parts of KMT

-gas particles are tiny and far apart

-always have elastic collisions

-always in motion

-no forces of attraction

-temperature is proportional to kinetic energy

Acids are

-sour

-react with metals

-pH>7

Bases are

-bitter

-slippery

-pH<7

MaVa=MbVb the formula for a titration

Litmus paper used to determine the pH of a solution

If the litmus paper turns red the solution is acidic

If the litmus paper turns blue the solution is basic

If the litmus paper turns green the solution has a neutral pH

Neutralization the reaction of hydronium ions and hydroxide ions to form water molecules

Collection of Gas over Water

Problem:

193 mL of O2 was collected over water on a day when the atmospheric pressure was 762 mmHg. The temperature of the water was 23.0 o C. How many grams of oxygen were collected?

Strategy:

Use Dalton's law and the vapor pressure of water at 23.0 o C to correct the pressure to units of atmospheres.

PT = Poxygen +Pwater

At 23.0 o C the vapor pressure of water is 21.1 mmHg. (This can be found on a vapor pressure table.)

762 mmHg = Poxygen + 21.1 mmHg

Poxygen = 762 mmHg - 21.1 mmHg

Poxygen =741 mmHg

Convert the corrected pressure to atmospheres.

(741 mmHg) (1 atm / 760 mmHg) = 0.975 atm

Use the ideal gas law to find out how many moles of gas were produced:

PV = nRT (remember to put volume in liters and temperature in Kelvin)

(0.975 atm) (.193 L) = n (.0821 L atm / mol K) (298 K)

n = (0.975 atm) (.193 L) / (.0821 L atm / mol K) (298 K)

n = 7.69 X 10-4 mol

Use the number of moles and the molecular weight of oxygen to find out how many grams of oxygen were collected.

(7.69 X 10-4 mol) (32.0 g / 1 mol) = 2.46 X 10-2 g

A sublevel --- is an electron orbital. Sublevels are designated s, p, d or f. These sublevels or orbitals have

characteristic shapes which can be used to explain and predict the chemical bonds that atoms can form.

s, p, d, and f sublevels\s sublevels are spherically shaped. The p, d and f sublevels have more complex

shapes. s orbitals can hold a maximum of 2 electrons, p a maximum of 6 electron, d a maximum of 10

electrons, and f a maximum of 14 electrons. The sublevel occupied by any electron is determined by the

electron's angular momentum quantum number, l. It is found by solving the Schrodinger equation,

allowing us to find probability distributions for an electron in an atom. For example, we can say that an

electron in a hydrogen atom's 1s sublevel will be found 99 percent of the time somewhere in a sphere

with a given radius around the nucleus. This is the reason we can draw the s sublevel as a sphere.