HONORS CHEMISTRY SEMESTER 1 & 2

Properties of Matter

Radiation and Decay

Atomic Theory

Half Life

Discovery of the Electron

Nuclear Chemistry

Discovery of the Nucleus

Rutherford's Gold Foil Experiment (discovered nucleus)

J.J Thompson (discovered electron)

Physical Change

Chemical Properties

Chemical Change

Physical Properties

A chemical change occurs whenever a new substance is made

A physical change affects only the physical properties of matter

Chemical properties are only identified by trying to cause a change

A physical property is a property that can be determined without changing the nature of the substance

Dalton's Atomic Theory

All matter is composed of extremely small atoms called atoms

Atoms of a given element are identical in size, mass, and other properties

Atoms of different elements differ in size, mass, and other properties

Atom cannot be subdivided, created or destroyed

Atoms of different elements combine in simple, whole number ratios to form chemical compounds

Modern Atomic Theory

All matter is composed of atoms

In chemical reactions, atoms are combined, separated or rearranged

Atoms cannot be subdivided, created, or destroyed in ordinary chemical reactions

Atoms of an element have a characteristic average mass which is unique to that element ( it can in nuclear reactions )

Atoms of any one element differ in properties of atoms of another element

Used cathode ray tube to prove the presence of a negatively charged particle

Cathode rays that identical properties regardless of the element. Therefore all elements must contain a negatively charged particle

Atoms are neutral, so there must be a positive particle in the atom to balance the negative charge of the electrons

Elements have very little mass that atoms had to contain something that accounted for most of the mass

Fired alpha particles (helium nuclei) at a thin sheet of gold foil. When any of the particles hit the foil, it was recorded.

Most of the particles passed right through

Some of the particles were deflected onto the gold foil

Very few particles were greatly deflected

Since some of the alpha particles were being reflected, it showed that something was in the middle of the atom ( nucleus ). The alpha particles are positive, so the nucleus also had to contain a positively charged particle

J.J Thompson developed the "plum pudding" model. This model stated that the electrons floated around in a positive "pudding".

Rutherford developed the Rutherford model. This model stated that the electrons orbited the protons.

Chemical Reaction

Nuclear Reaction

Atoms often converted into atoms of another element

Reaction influenced by particle size, temperature, etc.

Occurs when bonds are broken

Many nuclear reactions involve protons, neutrons, and electrons

Occurs when nuclei emit particles

Involves the valence electrons of an atom

Electron Orbitals

Alpha Decay

Gamma Emission

Gamma Radiation

Beta Radiation

Alpha Radiation

Composition is the same as helium nuclei

Charge on helium nuclei is 2+

Mass is 4 amu

Can be shielded from by paper

Occurs when a unstable nucleus emits a particle composed of 2 protons and 2 neutrons

Most ionizing out least penetrating of all the types of radiation

Loss of an alpha particle means; atomic number decreases by 2, and the atomic mass decreases by 4

Occurs when an unstable nucleus emits an electron

10 times more penetrating that alpha radiation, but is half the ionization

When an atom loses a beta particle; atomic number increase by 1 and mass number stays the same

Beta Decay

Composition is the same as an electron

Charge is 1-

Mass is 1/1873 (practically 0)

Can be shielded from by metal foil

Gamma rays are high energy photons of light

Composition is the high energy electromagnetic radiation

Charge is 0

Mass is 0 amu

Can be shielded from by lead or concrete

No loss of particles from a nucleus

No change in the composition of the nucleus (no change in atomic number or mass number)

Least ionizing, most penetrating

Half life is the time required for half of a radioactive isotope to decay into its products

To calculate mass remaining image

an orbital is a region within the atom that has the probability of holding an electron

P orbital is shaped like dumbells. Has 3 orbitals. p = 1

D orbital is shaped like a double dumbbell. Has 5 orbitals

F orbital is shaped like 4 dumbbells. Has 7 orbitals.

S orbital is shaped like a sphere. Has 1 orbital.

Spectra

When atoms of molecule absorb energy, that energy is often released as light energy

Principles

Aufbau Principle

Electrons fill up the lowest energy levels first

Pauli Exclusion Principle

Any orbital may only contain 2 electrons

Hund's Rule

Electrons fill equal energy levels before pairing up

Heisenburg Uncertainty Principle

One cannot both simultaneously determine both the position and momentum of an electron

Quantum Numbers

Quantum numbers act like the address for an electron

Principle Quantum Number

Angular Momentum Quantum Number

Magnetic Quantum Number

Spin Quantum Number

Indicates orbital energy levels

Denotes the orbital in which the electron is in. s=0, p=1, d=2, and f=3

Orbital orientation

Denotes the direction of spin or an electron within a magnetic field

Bonding

Ionic Radii

Cations are positively charged electrons

Anions are negatively charged electrons

A polyatomic ion is a molecular ion consisting of 2 or more atoms covalently bonded

A monoatomic ion is a molecular ion that consists of only 1 element

Covalent bonds are when two atoms share electron between them

Ionic bonds are when one atom takes electrons from another atom

Nonpolar covalent bonds are when atoms share electrons equally between each other

Polar covalent bonds are when electrons are not equally shared between the two atoms

Metallic bonds are bonds that occur in between two metals. During this bond, the valence electrons delocalize. This forms the "sea of electrons".

Atoms bond because of nucleus-to-nucleus repulsion, electron-to-electron repulsion, or nucleus-to-electron attraction

HONC Rule: hydrogen and halogens forms 1 bond, oxygen and sulfur form 2 bonds, nitrogen and phosphorus form 3 bonds, and carbon and silicon form 4 bonds

Lewis structures are a way to depict the valence electrons of a compounds

Lewis structures often have lone pairs. Lone pairs affect the relative sizes of repulsion and interaction

VSEPR Molecular Geometry

VSEPR allows for us to find the shape and angle of a certain compound

To find VSEPR, you need to use the AXE rule. The X stands for the bonds between each atom (even triple or double bonds count as one). The E stands for the lone pairs. Then you find the corresponding shape and angle in the VSPER chart

Types of Reaction

Combustion reactions: the products include carbon dioxide and water

Decomposition reaction: when a substance breaks down into other materials

Synthesis reaction: when materials combine to make a substance

Stiochiometry

Stiochiometry is the calculation of relative quantities of reactants and products in chemical reactions

Empirical Formulas

formula that gives the whole number proportion of the atoms in a compound

To find empirical formula (rhyme): % to mass, mass to mole, divide by small, multiply till whole

Gas Laws

Ideal Gases (Kinetic Molecular Theory): ideal gases are imaginary gases that perfectly fit all the assumptions of KMT

Boyle's Law : pressure is inversely proportional to volume when temp is held constant
P(1)V(1) = P(2)V(2)

Charles' Law: the volume of a gas is directly proportional to temperature and extrapolates to zero at zero Kelvin
V(1)/T = V(2)/T

Gay Lusssac's Law: the pressure and temperature of a gas are directly related, provided that the volume remains constant
P(1)/T(1) = P(2)/V(2)

The Combined Gas Law: expresses the relationship between pressure, volume, and temperature of a fixed amount of gas
P(1)V(1)/T(1) = P(2)V(2)/T(2)

Avogadro's Law: for a gas at constant temperature and pressure, the volume is directly proportional to the number of moles of gas (at low pressures)
V(1)/n(1) = V(2)/n(2)

Collisions between gas particles and between particles and the walls of the container are elastic collisions (no energy lost)

Gases consist of tiny particles that are far apart relative to their size

Gas particles are in constant, rapid motion (therefore possessing kinetic energy as it is the energy of motion)

There are no forces of attraction between gas particles in an ideal gas ( so it can never be a liquid)

REAL GASES DON'T BEHAVE IDEALLY!!!

Pressure

Nature of Gases

Gases expand to fill their containers

Gases are fluid.. they flow

Gases have low density

Gases are compressable

Gases effuse and diffuse

Diffusion is spreading out

Effusion is gas escaping from a sealed container

Pressure is caused by the collisions of molecules with the walls of a container

The units for pressure is an atmosphere

Standard Temperature and Pressure (STP)

Pressure : 1 atm

Temperature: 0 degrees Celsius, 272 Kelvins

click to edit

Ideal Gas Law: PV = nRT

P: pressure in atm

V = volume in liters

n = number of moles

R = proportionality constant

0.08206 (pressure is in atm, when volume in liters, temperature is in Kelvins)

8.314 (when pressure is in KiloPascals) (KPa)(volume in liters, temperature in Kelvins)

62.4 (when pressure is in mmHg/torr, volume in liters, temperature in Kelvins

At STP, the density of a gas is molar mass/22.4L

Thermochemical Equations

Specific Heat

the amount of heat required to raise the temperature of 1 gram of substance by 1 degree Celsius

Calorie

the heat required to raise the temperature of 1 gram of water by 1 Celsius degree

Calculations

q = mcAT (the A is actually a triangle)

m : mass (in grams)

Q = heat lost or gained

(triangle)t: temperature change

c : specific heat

Latent Heat of Phase Change

solid to liquid: 6.01 KJ/mol or 333 J/g

liquid to gas: 40.7 KJ/mol or 2240 J/g

Chemical Kinetics

Collision model

Collisions must have enough energy to produce the reaction

Reactant must have the proper orientation to allow the formation if new bonds

Rate Law

Rate = k(A)^n(B)^m

When molecules collide into each other all the time, but when they hit each other just right, a reaction will occur

Chemical Equilibrium

If a small value of "k" is signified, reaction is "reactant-favored"

Product-favored Equilibrium

If any large value for k is signified, the reaction is "product favored"

if "k" is any value greater than 1

When equilibrium is achieved, most reactant has been converted to product

If "k" is any value greater than 0 but less than 1

when equilibrium is achieved, little reactant has been converted to product

Law of Mass Action: products divided by reactants to the power of coefficients

SOLIDS AND LIQUIDS CAN NEVER BE A PART OF THE REACTION, ONLY AQUEOUS AND PARTIAL PRESSURES

Le Chatelier's Principle

A system undergoes a temporary shift in order to restore equilibrium

Solving for Equilibrium Concentration

Step 1: Write law of mass action

Step 2: ICE table

Step 3: Plug the equilibrium concentrations into our equilibrium expression, and solve for x

you will get 2 answers; if you get a negative answer it is not valid

if you get two positive answers, plug them back in and whichever causes your answer to be negative is not valid

Acids and Bases

Acids

Bases

Juices/Fruits

Tart, sour, sharp taste

They are electrolytes (conduct electricity)

React with metals

Common as aqueous and liquid

Common as solids

Slippery to the touch

Cleaning products

Calculating pH and pOH

Produce hydrogen ions

Produce hydroxide ions

pH = -log10 (H+)

pOH = -log10 (OH-)

pH + pOH = 14

Disassociation of Acids

Weak acids disassociate less than 5% in solution