General Chemistry Flashcards
Principle quantum number
(n) – larger the value = higher energy level and radius of electron shell
max # of e- in a shell = 2n^2
Azimuthal Quantum number
(l) angular momentum l=0 --- s l=1 --- p l=2 --- d l=3 --- f max # of electrons within subshell = 4l + 2
Hund’s Rule
within electron sub shell, e- will only begin pairing up once all orbitals are half-filled
Paragmagnetic
unpaired e- orient to align with magnetic field
–meaning that a magnetic field will cause parallel spins in unpaired electrons and cause an attraction
Diamagnetic
paired electrons will be slightly repelled by a magnetic field
Ionization Energies (Periodic Table)
Increasing moving to the right and up
Electron Affinity (Periodic Table)
Increasing moving to the right and up (just like ionization energy)
Atomic and Ionic Radii (Periodic Table)
increases moving to the left and down
Alkali Metals (Periodic Table)
Group 1
Alkaline Earth Metals (Periodic Table)
Group 2
Halogens (Periodic Table)
Group 17
Noble Gases (Periodic Table)
Group 18
Stable with incomplete octet (5)
Hydrogen H (2) Helium He (2) Lithium Li (2) Beryllium Be (4) Boron B (6)
Stable with expanded octet
elements in group 3 (or greater) Phosphorus P (10) Sulfur S (12) Chlorine Cl (14)
Ionic Bonds
one low ionization with atom of high electron affinity
typically between metal (become cation) and nonmetal (becomes anion)
Physical properties:
very high melting and boiling points
dissolved readily in water and other polar solvents
great conductors
covalent bonding
e- pair shared between 2 atoms, how they are shared determines polarity
Typically between two metals
Physical Properties:
weak intermolecular interactions
tend to have lower boiling and melting points
Coordinate Covalent Bonds
both shared e- originate from the same atom
Lewis Acid
any compound that will accept lone pair of e
lewis Base
any compound that will donate a lone pair of e
electronic vs. molecular geometry
electronic: spatial arrangement of electron pairs around central atom
molecular: spatial arrangement of only bonding pairs (coordination # determines molecular geometry)
Intermolecular Forces (weakest to strongest) 3
Dispersion forces then dipole-dipole interactions then H bonding
Dispersion Forces
attractive and repulsive interactions (rapidly)
Important key element for why noble gases can liquify
Dipole-Dipole interactions
oppositely charged ends orient to be closer together
longer duration of attraction
Hydrogen Bonding
strong
no sharing or transferring of electrons (no actual bond)
Only exists in HIGHLY electronegative atoms
high boiling points
Combination Reactions
2 or more reactants form 1 product
Decomposition Reactions
one reactant forms 2 or more products
usually due to heating, high freq. radiation, electrolysis
Combustion reaction
involves oxidation (hydrocarbon fuels, or S, or sugars) products: CO2, H2O is almost always present
Single Displacement Reaction
1 atom or ion in a compound is replaced with another
RedOx Rxns
Double Displacement Reaction
elements of 2 compounds swap to form 2 new compounds
Neutralization Reactions
type of double displacement
acid reacts with base to produce a salt
Three types of systems
isolated, closed, open
Isolated System
cannot exchange energy (heat or work) OR matter with surroundings
Closed System
can exchange energy (heat or work), but NOT matter with surroundings
Open System
Can exchange BOTH energy (heat and work) and matter with surroundings
First law of thermodynamics
deltaU = Q - W
Four types of Processes
Isothermal Process
Adiabatic Process
Isobaric Process
Isovolumetric Process
Isothermal Process
system’s temperature is constant = U is constant
U is constant (deltaU=0)
Q = W
Adiabatic Process
no heat exchange, thermal energy is constant
Temperature is not held constant
Q = 0, deltaU = -W
Isobaric Process
Pressure is held constant
Isovolumetric Process
(Isochoric Process)
Volume is constant, no work is being done
deltaU = Q
State Functions
P, density, T, V, enthalpy (H), Internal energy (U), Gibbs Free Energy (G), Entropy (S)
independent of path taken, but they relate to eachother
standard conditions versus standard Temperature and Pressure
Standard conditions = 25C (298K), I atm P, I [M] = used for kinetics, equilibrium, and thermodynamics
STP = 0C (273K), I atm P = used for ideal gas calculations
deltaQ > 0
Endothermic Reaction
deltaQ < 0
Exothermic Reaction
Bond formation (endothermic or exothermic?)
Exothermic process
Bond dissociation (endothermic or exothermic?)
Endothermic Process
Solvation
“Dissolution”
breaking of intermolecular interactions between solute molecules and solvent molecules to form new interactions together
Solvation: Exothermic reaction
when new interactions are STRONGER than original ones
Favored at low temperature
Solvation: Endothermic reaction
when new interactions are WEAKER than original ones
favorite at high temperatures
Solvation: Ideal Solution
when overall strengths between original and new interactions are approximately equal
Two prominent solubility rules
- All salts with ammonium (NH4+) and alkali metals (group 1) cations are water soluble
- All salts with nitrate (NO3-) and acetate (CH3COO-) anions are water soluble
Ion Product (IP)
allows you to determine where the system is with respect to equilibrium position
IP < Ksp
not at equilibrium
“unsaturated”
Dissolution is thermodynamically favored
IP > Ksp
Beyond equilibrium
“supersaturated”
Thermodynamically unstable
IP = Ksp
at equilibrium
saturated solution
“molar solubility”
Kf constant
formation/stability constant
significantly larger than Ksp
Ka constant
acid dissociation constant
=Products/Reactants
=higher value is a weaker acid (higher dissociation in more reactive acids)
Kb constant
base dissociation constant
similarly to Ka
Q < Keq , deltaG < 0
reaction proceeds in the forward direction
Q = Keq , deltaG = 0
reaction @ dynamic equilibrium
Q > Keq , deltaG > 0
reaction proceeds in the reverse direction
Le Chatelier’s Principle
3 main types of stress
Concentration, pressure/volume, temperature
Le Chatelier’s Principle: increase [R], decrease [P]
increase [R], decrease [P] = shift reaction to the right
vice versa will shift to the left
Le Chatelier’s Principle: increase P, decrease V
increase P, decrease V = shift in direction of fewer mols of gas
vice versa will shift towards more mols of gas
Le Chatelier’s Principle: increasing/decreasing T of Endothermic Reaction
increasing T will shift rxn to the right
decreasing T will shift rxn to the left
Le Chatelier’s Principle: increasing/decreasing T of Exothermic Reaction
increasing T will shift rxn to the left
decreasing T will shift rxn to the right
Strong Bases
NaOH Sodium Hydroxide
KOH Potassium Hydroxide
Strong Acids
HCl: hydrochloric acid HBr: hydrobromic acid HI: hydroiodic acid H2SO4: sulfuric acid HNO3: nitric acid HClO4: perchloric acid
Electrochemical Cells
- any cell with red-ox reactions
- anode: site of oxidation
- cathode: site of reduction
- e flow anode to cathode
- current flows cathode to anode
Galvanic (voltaic) Cell
-spontaneous reaction (deltaG<0) w/ positive electromotive force
-anode (-) charge
-cathode (+) charge
(electromotive force (+) and deltaG (-) )
Electrolytic Cells
-nonspontaneous reactions (deltaG>0) w/ negative electromotive force
-anode (+) charge
-cathode (-) charge
(electromotive force (-) and deltaG (+) )
3 type of rechargeable battery cell systems
- lead-acid battery
- nickel-cadmium batteries
- nickel-metal hydride (NiMH)
Lead-Acid battery
discharging: Pb anode and PbO2 cathode concentrated in H2SO4
charging: PbSO4- electrodes are dissociated to restore original Pb and PbO2 electrodes
- low energy density
Nickel-Cadmium Battery
discharging: Cd anode, NiO(OH) cathode in concentrated KOH
charging: Ni(OH)2 and Cd(OH)2 electrodes are dissociated
- high energy density than lead-acid
Nickel-Metal Hydride Battery
-replaced Ni-Cd batteries
-higher energy density
surge content: above average content @ start of discharge phase
concentration cell
specialized galvanic cell
-both electrodes are made of the same material
-concentration gradient causes movement of charge
(electromotive force (0) and deltaG (0) )
relationship between electromotive force and Keq constant
Keq > 1 = E cell is +
Keq < 1 = E cell is -
Keq = 1 = E cell is 0
Pauli Exclusion Principle
no 2 e- can possess the same set of 4 quantum numbers
Aufbau Principle
e- will fill lower energy orbitals before filling higher energy orbitals
Pauli Exclusion Principle
no 2 e- can possess the same set of 4 quantum numbers
Aufbau Principle
e- will fill lower energy orbitals before filling higher energy orbitals
Nucleophiles
negative charge
long pairs of e- or pi bonds
amino groups are common
Electrophiles
positive charge
alcohols, aldehydes, ketones, carboxylic acids
Oxidation of:
primary alcohol
aldehyde
secondary alcohol
primary = aldehyde, or carboxylic acid
aldehyde = carboxylic acid
secondary alcohol = ketone
(tertiary alcohol cannot be oxidized)
