Please enable JavaScript.
Coggle requires JavaScript to display documents.
HONORS CHEMISTRY SEMESTER 1 & 2 (Gas Laws (Ideal Gases (Kinetic…
HONORS CHEMISTRY SEMESTER 1 & 2
Properties of Matter
Physical Change
A physical change affects only the physical properties of matter
Chemical Properties
Chemical properties are only identified by trying to cause a change
Chemical Change
A chemical change occurs whenever a new substance is made
Physical Properties
A physical property is a property that can be determined without changing the nature of the substance
Radiation and Decay
Alpha Decay
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
Gamma Emission
Gamma rays are high energy photons of light
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
Gamma Radiation
Composition is the high energy electromagnetic radiation
Charge is 0
Mass is 0 amu
Can be shielded from by lead or concrete
Beta Radiation
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
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
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
Atomic Theory
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
In chemical reactions, atoms are combined, separated or rearranged
Modern Atomic Theory
All matter is composed of atoms
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
Half Life
Half life is the time required for half of a radioactive isotope to decay into its products
To calculate mass remaining
To calculate time
https://www.google.com/search?q=half+life+formula&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi2qaC68pLYAhVOz2MKHcxBCPQQ_AUICigB&biw=1280&bih=726#imgrc=i1sSP4-oFw0AwM
:
Discovery of the Electron
J.J Thompson (discovered electron)
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
J.J Thompson developed the "plum pudding" model. This model stated that the electrons floated around in a positive "pudding".
Nuclear Chemistry
Chemical Reaction
Reaction influenced by particle size, temperature, etc.
Occurs when bonds are broken
Involves the valence electrons of an atom
Nuclear Reaction
Atoms often converted into atoms of another element
Many nuclear reactions involve protons, neutrons, and electrons
Occurs when nuclei emit particles
Discovery of the Nucleus
Rutherford's Gold Foil Experiment (discovered nucleus)
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
Rutherford developed the Rutherford model. This model stated that the electrons orbited the protons.
Electron Orbitals
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
Indicates orbital energy levels
Angular Momentum Quantum Number
Orbital orientation
Magnetic Quantum Number
Denotes the orbital in which the electron is in. s=0, p=1, d=2, and f=3
Spin Quantum Number
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
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
Ionic bonds are when one atom takes electrons from another atom
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
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!!!
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)
Pressure
Pressure is caused by the collisions of molecules with the walls of a container
The units for pressure is an atmosphere
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
Standard Temperature and Pressure (STP)
Pressure : 1 atm
Temperature: 0 degrees Celsius, 272 Kelvins
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
When molecules collide into each other all the time, but when they hit each other just right, a reaction will occur
Rate Law
Rate = k(A)^n(B)^m
Chemical Equilibrium
If a small value of "k" is signified, reaction is "reactant-favored"
If "k" is any value greater than 0 but less than 1
when equilibrium is achieved, little reactant has been converted to product
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
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
Juices/Fruits
Tart, sour, sharp taste
They are electrolytes (conduct electricity)
React with metals
Common as aqueous and liquid
Produce hydrogen ions
Bases
Common as solids
Slippery to the touch
Cleaning products
Produce hydroxide ions
Calculating pH and pOH
pH = -log10 (H+)
pOH = -log10 (OH-)
pH + pOH = 14
Disassociation of Acids
Weak acids disassociate less than 5% in solution
