Chemistry:Vishnu Kuriseti
click to edit
Bonding and Structure
Reactions
Periodic Trends
Stoichiometry
Electrons
Chem Basics
click to edit
Solutions
Kinetics
Thermochemistry
Equilibrium
click to edit
Advanced Chemical Ratios
click to edit
Avg Atomic Mass
Atomic numbers
Prop changes
Math Review
To smaller Unit->multiply
to Larger unit->divide
Metric(kilo hecto deka...)
Sig Figs
Dimensional Analysis
Dalton's Atomic theory
atoms have avg mass b/c of isotopes
nucleus
small
dense
postively charged
Atomic number=# protons
mass number=protons+neutrons
isotopes differ masses because of differing neutrons
click to edit
rewrite as fractions(conversion factors)
Cancel units top and bottom
Non-Significant
Significant
Leading zeros
Nonzero integers
Captive Zeros
trailing zeros(sometimes)
Multiplication-least number of sig figs
Addition/Subtraction-Least number of decimals
Extensive-mass,volume,energy
Intensive-melting and boiling point and density
Homogenous-composition is uniform
Heterogenous- varies from one region
physical change-alters state and appearance
chemical change- alters composition/identity
weighted avg
Avg atomic masses is avg of natural isotopes
% abundance(use to solve for avg mass)
Orbital Diagrams
Atomic Absorption
click to edit
Afbau-e- fill lowest possible energy level first
Pauli exclusion-no 2may have the same set of 4 quantum numbers
Hunds Rule-electrons fill fill each orbital before pairing
Noble gases have full valence shell
Use noble gases sort of as a short cut when writing configurations
Ions have a charge
cation lose e-
anion gain e-
Wavelengths can tell us energy gaps and transfer of e-
Emission-seeing wavelengths of energy released
Absorption-seeing missing bands of energy being absorbed
Ionic Radius
Atomic Radius
Ionization Energy
Electronegativity
Electron Affinity
Reactivity
1/2 distance between boded nuclei
increase down decrease to right
Zeff=Z-S
radius of ion
cation smaller anion bigger
energy required to remove e-
decrease down increase to right
Measure of ability an atom has to attract other e- of other compunds
decrease down increase right
HOw much energy released when atom get e-
decrease down and increase to the right
Metals increase down
non metals increase up
Bonds form to lower potential energy
Balancing
Types
Predicting Products
g=gas
s=solid
l=liquid
aq=aueous
Change coefficients to make sure the amount of reactants and products is the same
law of conservation
Synthesis- 2 thing into 1
Decomposition-1 thing into 2 things
Combustion-Burning(almost always has hydrocarbon)
Single Replacement-Swapping one element
Double replacement-Swapping 2 elements
Turn into formula
identify reaction
write products
Balance equation
Use Activity series and solubility chart to help predict products
Ionic Bonds
Transfer of e-
Metal+nonmetak
Between negative and positive charge
Covalent
Share electrons
NOnmetals+nometals
Metallic Bonds
Createse seas of e-
Only metals
Poly and Monoatomic Ions
Use periodic table to find charge for cation or anion
Neutral Compounds
Crossing OVer
Cancel out charges
Lowest possible combo to be neutral
Lewis Structture
Bonds occur with valence e-
octet rule-atoms want 8e-
Least electronegative goes in the center
Symmetry
bond=2e-
click to edit
AXE
A=central atom
X=#bonded atoms
E=lone electron pairs on central atom
Tells us about Electronic and Molecular geometry
Polar when electron not shared equally and non polar when shared equally
IMFs
Intramolecular Forces are inside and Intermolecular is between neighboring molecules
London Dispersion Force-Weak and temporary caused by unequal electron distribution(Everything has LDF)
Dipole-Dipole-Only in Polar Molecules and is when partially negative portion attracts to a partially positive portions
Hydrogen BOnding- Must have H and is strongest bond
Bulk Solids
Metallic(weakest)
Ionic Lattice(middle)
Network Covalent(strongest)
Use coefficients of the rxn for # moles of each chemical
Mole ratios Use them in dimensional anlysis
Percent yield=actual yield/Theoretical yield *100%
Avogadros Number = 6.02E23 objects(use for moles<->objects
Use molar mass for moles<->grams
Molar mass is grams per mole
Limiting Reagent-Reactant that is used up first in a rxn
If 2 starting values then its a limiting stoich problem
XS reactant- reactant you have left over of
Use dimensional analysis for Have vs Need
Percent comp= elements mass/molecules mass *100%
Empirical Formula- Reduced formula Ex:H6C6=HC
Ionic formulas always empirical and Covalent sometimes
Percent to mass
mass to moles
Divide by small
Multiply by whole
MOlecular Formula
Find mol. mass of empirical
divide by molecular formula by empirical formula mass
Multiply empirical formula subscripts by multiplier
Gas Laws
Absolute zero=0K
Boyle's law- P1V1=P2V2
Charles' Law- V1/T1=V2/T2
K=Celsius+273
Gay-Lussac's- P1/T1=P2/T2
Avogadro's Law- V1/n1=V2/n2
Combined Gas Law- P1V1/T1=P2V2/T2
Ideal Gas Law-PV=nRT(R is ideal gas constant)
Density= mass/volume
Use these equation to solve for unknowns
Specific heat is the amount of energy needed to raise the temp of 1 gram by 1 degree celsius
Specific Heat Units- J/g*degrees celsius
Q=MCdeltaT
C=specific heat
Q=energy lost/gained
m=mass
delta T=change of temp
+Q=endo
-Q=Exo
Calorimetry
Use 2 MCAT for each substance
1st law of thermodynamics is energy can't be created or destroyed
Q=-Q
Heating/Cooling curves
IF negative slope then cooling
IF positive slope then heating
Flat lines mean phase changes
MCAT for sloped lines and Q=ML for phase changes
Solute is the substance thats is being dissolved in asolution
Solvent is the substance that is being dissolved into
Solution is solute+solvent
Solubility is the amount of solute that can be dissolved at a certain temp
Saturated solution- max amount of solute dissolved
unsaturated solution is less than the max solute dissolved
super saturated solution is more than the max amount of solute dissolved
Colloids are when large particles are suspended in a substances
Dissociate- when ionic compound has its ionic bond disrupted by solvent molecules and breaks apart
Mass percent=mass of solute/mass of solution #100%
ppm=mass of solute/mass of solution *1,000,000
Grams per Liter=Mass of solute/Volume of solution
Mole Fraction=Xa=na/na+nb
M= moles of solute/Liter of solution
Dilutions M1V1=M2V2
Related to speed
Collision theory is that reactants have to collide to reacte
Activation energy is the min amount of energy required to react
factors of rxn rate
temp
concentration/pressure
surface area
Catalysts
doesn't get used up in rxn
Lowers AE
More effective collisions
Rate determining step is the slowest step
Can find rate by using the tangent line to a specific point on the graph
Rate Law K[A]^x[B]^y
x is the order for A and y is order for B
Order is the mathematical effect of an individual reactants concentration has on the overall rate
K is the rate constant
Rxns go forwards and back
Equilibrium is the point where the forward rxn occurs ta the same rate as the reverse rxn
Le chat's principle-if stress is applied to rxn @ equilibrium then the rxn changes to relieve the stress and finds new equilibrium point
Stresses
Temp change
Concentration change
Pressure/volume changes
Keq=[products]/[reactants]
USe partial pressure if no concentrations
k= q then @ equilibrium
k<Q then too many products
K>Q then too many reactants
ICE table= Initial, Change, Equilibrium
USe quadratic formula to solve for x and find the [] @ equilibrium
Can use the 5% rule if if K<1 and x is less than 5% of the initial []
Acid Bases
Bases
Acids
Bitter
Slippery
Commonly solids
Sour sharp taste
conduct electricity(are electrolytes)
React with metals
Arrhenius-Acids make H+ ions in aq solutions and bases make OH-
Bronsted-Lowry-Acids donate protons and Bases accept them
Lewis- Acids accept electron pairs and bases donate them
Arrhenius is most specific and Lewis is least specific
pOh is opposite of pH
pH measures power of hydronium ions
pH=-log[H+]
pOH=-log[OH-]
pH+pOH=14
Binary acid=hydrogen+highly electronegative element
Oxyacids are hydrogen +oxygen+a third element