Law of Conservation Of Mass
The mass of reactants equals the mass of the products
Dimensional Analysis
Using relationships to get from one unit to another
Rutherford's Gold Foil Experiment
Alpha rays shot at a piece of metal. Most went through but some of the rays came back. This means the positive rays must have hit another positive mass (nucleus).
Mass Number
number of protons and neutrons
Atomic Number
number of protons
Isotopes
Elements with the same number of protons but different numbers of neutrons
Electrolyte
Aqueous solution that contains ions and therefore conducts electricity
Redox Rxn
Electrons are transferred in this rxn. This changes the charges of elements in the rxn.
Equivalence Point
When moles of acid present are stoichiometrically equal to the moles of base present.
Potential Energy
Stored or positional energy. When objects attract this is needed to move them apart.
Exothermic
During this rxn, heat is released
Endothermic
During this rxn, heat is absorbed
1st Law of Thermodynamics
States the energy of the universe is constant, and energy cannot be created nor destroyed.
Heat Capacity (C)
The amount of energy required to raise an entire substance by 1�C
Heat of Vaporization/Fusion
Energy required to convert a liquid at its boiling point to a gas. Energy required to convert a liquid at its freezing point to a solid.
Hess's Law
Not all compounds can be synthesized from their elements.
Bomb Calorimetry
Volume during this calorimetry rxn is constant.
UV Catastrophe
In classical physics, the intensity of the light emitted would continually increase as energy was applied. Discovery that the intensity of light emitted hit a maximum and then decreased.
Bohr's Atomic Theory
Said that electrons exist in the atom only on certain allowed or bits. These orbits had specific energies. Allowed energies of electrons are quantized. When the electron releases to a lower orbit the atom releases the energy as light.
Heisenberg UP
It is impossible to determine the position and velocity of an electron simultaneously.
Schrodinger's QM Model
The behavior of an electron in an atom can be best described as a standing wave. Each wave function is associated with an allowed energy level for the electron. Assesses the probability of finding an electron with a given energy within a region of space.
Photoelectric Effect
Discovered that there was a certain energy threshold needed to eject electrons. Lots of low energy light was not enough to break this threshold. If the energy is high enough, electrons will be ejected.
Wave Partical Duality
Louis de Broglie came up with this idea that the electron can also be described as a wave.
Aufbau Principle
Says that electrons are assigned to shells and subshells of increasingly higher energy. Electrons will fill the lowest possible energy level.
Pauli Exclusion Principle
Says that no two electrons can have the same set of quantum numbers.
Hunds Rule
Says that the most stable arrangement of electrons is the one with the maximum number of unpaired electrons. (Empty bus seat rule)
Isoelectric
Atoms with the same number of electrons
Effective Nuclear Charge
Charge experienced by a particular electron in a multi-electron atom. Core electrons screen out the nuclear charge so the outer electrons don't feel it as strongly.
Shielding
Constant across periods because the number of core electrons is the same.
Atomic Radius
One half the distance between two nuclei. Increase down in nuclear charge means an attraction to the nucleus, and a decrease in _____. Increase in shielding across means an increase in distance from nucleus, so increase in ____.
Ion Size
Cations: lose an electron, so if they lose one then the nucleus pulls the remaining ones in tighter, resulting in a decrease in _____. Anions gain an electron, so they are allowed to move more freely, resulting in an increase in ______.
Ionization Energy
Energy it takes to remove an electron.
Electronegativity
The tendency of an atom to attract shared electrons.
Formal Charge
Total charge of an atom in a molecule. If it is unavoidable, the most electronegative element should have the most negative charge.
Polar Bonds
Result from the uneven sharing of electrons
Bond Order
The number of bonding electron pairs shared by two atoms
Bond length
The distance between the nuclei of two bonded atoms
Bond energy
The enthalpy change for breaking a bond in a molecule with reactants and products in the gas phase. Breaking bonds requires energy and making bonds releases it.
Ionic Compounds
Granular, soluble solids made from a metal and a non-metal. Electrostatic attractions hold these compounds together. Electrons are transferred when the bonds form.
Lattice Energy
The energy of formation of one mole of an ionic crystalline solid. An exothermic process that depends on the magnitude of ion charges (larger the charge, stronger the attraction, more negative ___) and the distance between the two ions (distance decreases, attraction increases, more negative _____).
Valence Bond Theory
By Linus Pauling, said that chemical bonding is the result of orbital overlaps. The probability of finding an electron in this overlap is very high.
Carbon's Diversity
This element has four valence electrons, because it can form four bonds. Can support multiple geometries.
Carbon's Stability
This element can make bonds that can only be broken with UV radiation, and will only react with nitrogen or oxygen when given a spark.
Isomers
Compounds with the same chemical composition but different structural formulas
Structural Isomers
Have the same elemental composition but different connections (e.g. 2 chlorines being on one carbon atom, or one on each atom)
Stereoisomers
Compounds with the same formula and a similar attachment of atoms. The molecules have different orientations in space.
Geometric Isomers
Can be either cis or trans.
Cis isomer
Attachments are on the same side of the double bond
Trans isomer
Attachments are on opposite sides of the double bond
Optical Isomers
Nonsuperimposable mirror images. Also known as chirol molecules.
Boyle's Law
Pressure and volume inversely related
Charles' Law
Volume and temperature directly related
G-L's Law
Pressure and temperature directly related
Avogadro's Law
Moles and volume directly related
Dalton's Law
Says the total pressure of a mixture of gases is equal to the sum of the pressures of the individual gases
Graham's Law
Says the rates of diffusion of gases are inversely proportional to the inverses of their molar masses.
Kinetic Molecular Theory
Each gas molecule has very little volume. Gas molecules are in constant random motion. All collisions are elastic. There is no attraction or repulsion between gas molecules.
Maxwell-Boltzman Distribution
Plots of the number of molecules vs. molecular speed. Either one gas at three temperatures, or three gases at one temperature.
Deviation of Real Gases
This deviation happens at high pressures and low temperatures.
Intramolecular Forces
Forces within a molecule
Intermolecular Forces
Forces of attraction between two different molecules.
Ion-Dipole
When molecules of water attract to positive Na ions and negative Cl ions in solution.
Dipole-dipole
Two polar molecules orient themselves so opposite charges attract. Partially positive hydrogen in one HF molecule will attract to the partially negative in another HF molecule.
Dipole induced dipole
Between a polar and a non-polar molecule. Polar molecules disturb the charge distribution of nearby non-polar molecules. The partially negative charge will repel the electron cloud of the other molecule causing TEMPORARY uneven distribution of charge.
London Dispersion
Occur between two non-polar molecules. When 2 np molecules interact their electron clouds can become distorted. This distorts the electron charge causing a quick dipole.
Hydrogen Bonding
Between the hydrogen of one molecule and the oxygen of another. This is an extreme dipole dipole force.
Vapor Pressure
The pressure that gas molecules exert over liquids. An example of dynamic equilibrium.
Boiling point
The temperature at which the vapor pressure of a liquid is equal to the external pressure of the atmosphere.
Triple point
The temperature and pressure at which all three phases of a substance coexist at equilibrium.
Critical Point
The temperature and pressure at which it is unable to increase the temperature and pressure any more.
Surface Tension
The energy required to break through the surface or to disrupt a liquid drop and spread it out into a film. The higher the IMFs the higher the _____.
Viscosity
The resistance to flow. High IMFs result in high ____.
Capillary Action
Explains why we see the meniscous in a cylinder. Adhesive forces between two different substances compete with cohesive forces that hold a liquid together.
Metallic Bonding
Metal ions share a sea of electrons. Electrons don't belong to a specific atom but belong to the entire lattice. A layer of protons, layer of electrons, and layer of protons.
Malleable
Able to be hammered into sheets
Ductile
Able to be drawn into wires
Alloys
A mixture of two metals which are stronger than the individual metals. The packing of the atoms is improved.
Network Covalent Solids
Very hard substances with very high melting points. Atoms are held together in an infinite 3D structure.
Allotropes
Different structural arrangements of the same element e.g. diamonds and graphite.
Amorphous Solids
Lack a regular structure, have a wide melting point range, shatter easily, and are difficult to identify. E.g. nylon, glass, plastics.
Miscible
Two substances that dissolve in each other
Immiscible
Two substances that do not dissolve in each other
Colligative Properties
Properties that depend only on the amount of solute in the solution and not on the identity of the particles
Raoult's Law
States the partial pressure of a solvent over a solution is equal to the vapor pressure of the pure solvent times the mole fraction of the solvent in solution.
Osmotic Pressure
The pressure created by the column of solution for a system at equilibrium.
Catalyst
Substances that speed up a reaction by lowering the activation energy.
Collision Theory
States that for a rxn to occur: reacting molecules must collide, reacting molecules must collide with sufficient energy, and molecules must collide in the correct orientation.
Law of Mass Action
Relates the concentration of products and reactants in a quantity called the equilibrium constant (K).
Reaction Quotient
Provides the same information as K except the reaction is not at equilibrium.
Arhennius Acids and Bases
A substance that ionizes in water to form H+/OH- ions.
Bronsted-Lowry Acids and bases
A substance that donates a proton (acid), a substance that accepts a proton (base)
Amphiprotic Acids/Bases
Compounds that can be both an acid and a base (like water)
Polyprotic Acids/Bases
Capable of donating more than one proton, capable of accepting more than one proton
Lewis Acids/Bases
Accept an electron pair (acid), donate an electron pair (base)
Complex Ions/Coordinate Complex
Ions bonded to often neutral molecular compounds/anions that have a net charge. Original charge doubled is the number of waters. Add the charges of the reactants to get the charge of the product.
Oxoacids
Contain an atom bonded to one or more oxygen atoms with hydrogen attached.
Inductive Effect
The more oxygen atoms bonded to the central atom, the more polar the OH bond. The more polar the OH bond the more likely dissociation will be.
Common Ion Effect
Occurs when the ionization of an acid/base is limited by the presence of a conjugate base or acid. Always shifts equilibrium to the reactant side and limits dissociation.