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Gen Chem

Terms in this set (263)

phase diagram phases
solid, liquid, gas
pressure unit conversions
1 atm
760 mmHg
760 torr
101.3 kPa
what is a boiling point?
the temperature at which the vapor pressure of the liquid equals the surface pressure
Standard Temperature and Pressure (STP) values
0 C
1 atm
22.4 L = 1 mol
avg speed of gas molecules = 481 m/s
What is the kinetic molecular theory?
The idea that matter is made from moving invisible particles

model of an ideal gas
what are the characteristics of an ideal gas?
1) gas molecules have no size (0 volume)
2) NO attractive/repulsive forces
3) completely elastic collisions (no KE lost)
4) Avg KE is proportional to the Temp of gas
ideal gas constant
R = 0.08206 L atm/mol K

R = 8.314 J/K mol
relationship between elevation and atmospheric pressure
as elevation increases, atmospheric pressure decreases

-gravity pulls air down
-air is less dense with increasing altitude
simple mercury barometer
measures atmospheric pressure
pressure vs. depth equation
P =ρgh
boyle's law
P1V1=P2V2

PV = constant
charle's law
V1/T1=V2/T2

V/T = constant
avogadro's law
V1/n1=V2/n2

V/n = constant
isovolumetric process
A process that occurs at constant volume in which the system performs no work

also called an isochoric process.

Energy = q
adiabatic process
A process in which no heat is transferred to or from the system by its surroundings

Energy = W
isothermal process
a thermodynamic process that takes place at constant temperature (no change in internal energy)

q+ W = 0
dalton's law
Ptotal = P1 + P2 + P3...

at constant volume and temperature, the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the component gases
partial pressure equilibrium constant
concentration and partial pressure equilibrium equation
real gases occur at _______ temp and ________ pressure. why?
low temp: intermolecular force is significant
high pressure: causes compression

LT HP
gas compressibility
compressibility = PV / nRT

compressibility < 1 means attractions between molecules
compressibility > 1 means non-zero volume
______ cal = ______ Joules
1 cal = 4.184 Joules
heat capacity definition and equation/units
added energy required to increase temp by 1 Kelvin

C = q/∆T

units: (J/K) or (cal/celcius)
specific heat capacity definition and equation/units
heat capacity per unit mass

q=mc∆T

units: (J/kg K) or (cal/g celcius)
coffee cup calorimeter has constant ________
pressure
bomb calorimeter has constant __________
volume
what does a calorimeter measure?
temperature as a reaction progresses
heat of fusion
the energy required to change a substance from solid to liquid at its melting point

q=mL (J/mol)
heat of vaporization
The amount of energy required for the liquid at its boiling point to become a gas
heat of sublimation
Heat of fusion + Heat of vaporization
sublimation
solid to gas
deposition
gas to solid
Which phase changes are endothermic?
melting, vaporization, sublimation

b/c they require heat and ∆H and ∆S are positive
critical point
point at which the distinction between liquid and gas cannot be made
a substance beyond the critical point is called __________
supercritical fluid
triple point
the temperature and pressure conditions at which the solid, liquid, and gaseous phases of a substance coexist at equilibrium
water phase diagram
solid-liquid line slope is negative (solid H20 is less dense than liquid)
normal boiling point
the boiling point of a liquid at a pressure of 101.3 kPa or 1 atm
pascal's law
...
henry's law
the solubility of a gas in a liquid is directly proportional to the partial pressure of that gas on the surface of the liquid

C = k x Pa
[gas] = constant x Gas Partial P
Raoult's Law
the vapor pressure of a solution is directly proportional to the mole fraction of solvent present

vapor pressure solution = mole fraction x vapor pressure liquid

ideal solutions
common oxidation states
Hydrogen = +1 (exception: -1 w/ a metal ex: NaH)
Oxygen = -2 (exception: -1 in a peroxide ex: H2O2)
Fluorine = -1

*the more electronegative atom gets to be negative!
oxidation state equation
valence electrons - nonbonding electrons - assigned bonding electrons

most electronegative atom gets assigned the bonding electrons
oxidation state of monoatomic ion?
equal to its charge
strong electrolye
completely ionize when dissolved in water

strong acids, strong bases, salts
weak electrolytes
partially ionize in water

weak acid, weak bases
Molarity
M = moles of solute/liters of solution
vapor pressure
pressure created by the molecule in the open space above a liquid at equilibrium

fixed at a given temp
nonvolatile solute
a solute with no vapor pressure

reduce the SA of the solution, so less molecules can break free
What molecules are always soluble?
Group 1 Ions (Li+, Na+, K+...)
Ammonium (NH4+)
Nitrate (NO3-)
Acetate (C2H3O2-)

GANA
what molecules are sometimes soluble?
Sulfate (SO42-)
insoluble with:
-Pb, Hg, Ag (PMS)
-Ca2+, Sr2+, Ba2+
Group 17 Ions (F-, Cl-, Br-...)
insoluble with:
-Pb, Hg, Ag (PMS)
what molecules are insoluble?
Carbonate (CO32-) and Phosphate (PO43-)
soluble with:
-Group 1 ions, NH4+

Hydroxide (OH-) and Sulfide (S2-)
soluble with:
-Group 1 ions, NH4+
-Ca2+, Sr2+, Ba2+
reducing agent
reducing agent contains the atom being oxidized
oxidizing agent
oxidizing agent contains the atom being reduced
electromotive force (emf)
-voltage when no charge is moving b/w the 2 terminals of a cell that are at different potential values

-Pressure to move exerted by the cell on the electrons

1V = J/C
where do electrons flow in a galvanic cell?
from anode to cathode
where does current flow in a galvanic cell?
from cathode to anode

opposite direction of electron flow
a spontaneous reaction has a ________ E° cell
positive E° cell
a nonspontaneous reaction has a _______ E° cell
negative E° cell
for a galvanic cell, the E° cell must be ________ and ∆G must be_______
positive E° cell
negative ∆G
for an electrolytic cell, the E° cell must be ________ and ∆G must be_______
negative E° cell
positive ∆G
concentration cell
a galvanic cell in which both compartments contain the same components, but at different concentrations
electrolytic cell
an electrochemical cell used to cause a chemical change through the application of electrical energy
anode and cathode of an electrolytic cell
anode is positive
cathode is negative

*opposite charges from galvanic
where do electrons flow in an electrolytic cell
from anode to cathode
oxidation and reduction in an electrolytic cell
AN OX
RED CAT
lead storage battery
-a battery (used in cars)
-anode is lead
-cathode is lead coated with lead dioxide
-the electrolyte is a sulfuric acid solution
nickel-cadmium battery
A type of rechargeable battery using nickel oxide hydroxide and metallic cadmium as electrodes.
anode charge (galvanic cell)
negative
cathode charge (galvanic cell)
positive
how is energy converted in a galvanic cell?
chemical E to electrical E
ionic conductor
electrolyte solution in the form of a salt bridge
salt bridge
A tube that allows the slow transfer of ions and maintains the neutrality of the electrolyte solutions.

Ex: KCl, KOH
heat of solution
ΔHsolution = ΔH1+ΔH2+ΔH3
How does pressure affect solubility?
Increasing the pressure increases the solubility of gases
how does temperature affect solubility of gases?
increasing the temperature decreases gas solubility

b/c greater KE means more gas particles can escape
how does temperature affect solubility of a solid?
endothermic rxn: increase in temp increases solubility

exothermic rxn: increase in temp decreases solubility
how does size of a gas affect solubility?
heavier/larger gases experience greater VDW forces, so they're more soluble
oxidation states on periodic table
disproportionation redox reaction
some atom is oxidized and reduced
solubility definition
Maximum amount of moles of a solute that can be dissolved in a given amount of solvent at a given temperature

mol/L
solubility product
Ksp
equilibrium constant for the dissociation of a solid salt to give its ions in solution
Ksp =
Ksp = [A][B]
solubility product equation
NO solids, NO pure liquids
common ion effect
an ion that is already in the solution and gets added, which affects the equilibrium and generally decreases solubility
which metals are very stable?
Cu, Ag, Au, Pt

they want to be neutral
reaction between a metal and water
yields metal ion + OH- + H2
electrolyte
a compound that forms ions in an aqueous solution and can conduct electricity
molality
m = moles of solute/kg of solvent
parts per million
ppm = mass of solute in solution / total mass of solution x 10^6
breaking bonds is _______
endothermic
forming bonds is_______
exothermic
standard reduction potential
indicates how likely a species is to be reduced under standard conditions (1M, 1 atm, 298 K)
are larger standard reduction potentials more or less favorable?
more thermodynamically favorable
for evaporation, the partial pressure of the gaseous phase is _____ the vapor pressure of the liquid phase
less than
boiling occurs when the vapor pressure _________ the atmospheric pressure
equals
melting point is the temp at which the solid's vapor pressure ________ the vapor pressure of the liquid phase
equals
when a nonvolatile solute is added to solution, the vapor pressure of solution ________ the vapor pressure of pure solvent
is less than
volatile solute
solute with vapor pressure
vapor pressure equation
Pv = XaPa + XbPb
precipitate colors
atoms with partially filled d orbitals will form a color b/c they absorb light in the visible spectrum
spectator ion
an ion that is not directly involved in a chemical reaction; an ion that does not change oxidation number or composition during a reaction
standard hydrogen electrode
Reference electrode based on the half-reaction 2H+ + 2e- --> H2
Consists of a platinum electrode in contact with a solution of a strong acid and hydrogen gas at STP
Nernst equation
Ecell= E°cell - (RT/nF) (lnQ)
used to determine reduction potential of a half cell
equation relating delta G and Ecell
Delta G = -nFEcell
anode and cathode in a concentration cell
cathode = higher concentration
anode = lower concentration
how do you calculate emf?
emf = E°cathode - E°anode
precipitation happens when Q ________ Ksp
Q > Ksp
units of rate
Molarity/sec

mol/L sex
rate determining step
the slowest step in a reaction mechanism that determines the overall rate of reaction
functions of a catalyst
-enhance product selectivity
-reduce energy consumption
-increase reaction rate
-lower Activation Energy
-increases steric factor (favorable collision)
why is activation energy always positive?
because it is the energy needed by the reactants to form a higher energy transition state
what is activation energy?
the difference between the energy of the transition state and the energy of the reactants
heterogeneous catalyst
A catalyst that is in a different phase from that of the reactant substances

works by adherence: reacting species clings to the surface of the catalytic medium

increasing the surface area of the catalyst increases the rate of reaction
homogeneous catalyst
a catalyst that is in the same phase as all the reactants and products in a reaction system

considers solubility
what is the rate constant influenced by?
temperature (incr temp = increase k)

solvent (depends on how they stabilize the rxn)
enthalpy of formation
the enthalpy change that accompanies the formation of a substance from the most stable forms of its component elements
radiation
thermal energy transfer via electromagnetic waves
Boltzmann's constant
k = 1.38 x 10^-23 J/K

used to determine the KE of particles in a fluid
gibbs free energy
energy available to do work

∆G = ∆H -T∆S
reaction order
indicates how changes in reactant concentration will influence the reaction rate
zero order reaction
rate = k
independent of concentration
first order reaction
rate = k[A]
second order reaction
rate = k[A]^2
rate = [A][B]
third order reaction
rate = k[A]^3
rate = [A][B]^2
rate = [A][B][C]
zeroth law of thermodynamics
A law that if two systems are separately found to be in thermal equilibrium with a third system, the first two systems are in thermal equilibrium with each other; that is, all three systems are at the same temperature. Also known as thermodynamic equilibrium.
enthalpy equation
∆H = ∆E + P∆V
entropy units
J/K
extensive property
a property that depends on the amount of matter/size in a sample

ex: volume, moles, energy
intensive property
a property that depends on the type of matter in a sample, not the amount of matter

ex: pressure, temp
average KE for a mole of particles in a fluid
KE = 3/2RT
average KE of a single molecule in a fluid
KE = 3/2kT

*k = boltzmann's constant
second law of thermodynamics
the entropy of the universe is always increasing
entropy equation
ΔS=Qrev/T
Third Law of Thermodynamics
entropy of a perfectly organized crystal at absolute zero is zero
∆H, ∆S, ∆G for a spontaneous reaction
- ∆G
- ∆H
+ ∆S
reaction quotient (Q) equation
relationship between K and Q
conduction
thermal energy transfer via molecular collisions

physical contact
how does pressure affect equilibrium?
depends on side w/ greater # moles of gas

increase in pressure: shift away from more moles
decrease in pressure: shift toward more moles
how does temperature affect equilibrium?
If the temperature is lowered - the equilibrium moves in the exothermic direction.
If the temperature is raised - the equilibrium moves in the endothermic direction.
kinetic products
-formed at lower temps
-have higher energy
-less stable
-formed quickly
-require smaller Ea

irreversible
thermodynamic products
-favored at higher temps
-have lower energy
-more stable
-require greater Ea
-formed more slowly

reversible
rate law
only includes concentration of reactants
first law of thermodynamics
total energy of a system is conserved
∆E = q + w
convection
thermal energy transfer via fluid movement
work
any energy transfer that is not heat

w = -P∆V
gibbs free energy and equilibrium equation
∆G = -RTln(K)
Arrhenius equation
catabolic
A process in which large molecules are broken down
anabolic
A process in which large molecules are built from small molecules
how does IMF strength influence boiling point?
stronger IMF = higher boiling point

ionic > H bonds > dipole > VDW
how does molecular weight influence boiling point?
increasing molecular weight increases boiling point

b/c increase surface area increases VDW
how does branching influence boiling point?
branching lowers the boiling point

b/c more branching means that it is harder for the functional groups to bond
ionic character
the greater the electronegativity difference the greater the ionic character
properties of covalent molecules
-low melting and boiling points
-liquids and gases at room temperature
-volatile
formal charge
valence electrons - nonbonding electrons - bonds
coordinate covalent bond
a covalent bond in which one atom contributes both bonding electrons
coordination number
number of coordinate bonds formed between the central atom and neighboring atoms
sigma bond
formed by overlap of hybridized atomic orbitals

lower in energy, more stable, and greater bond dissociation energy than a pi bond
pi bond
side-by-side overlap of unhybridized p orbitals
hybridization is the process by which ________ orbitals combine to form _______ orbitals
atomic orbitals combine to form hybrid orbitals
properties of ionic compounds
-high melting and boiling points
-conduct electricity
-solids at room temperature
induced dipole
a dipole temporarily created in an otherwise nonpolar molecule, induced by a neighboring charge
instantaneous dipole moment
Arise spontaneously in an otherwise nonpolar molecule

occurs when electrons move and distribute unevenly; can create an induced dipole in a neighboring molecule
dipole-dipole interactions
attractive forces that act between polar molecules in a liquid or solid
London dispersion forces
intermolecular attractions between instantaneous dipoles induced by momentary distortions in the distribution of electron clouds around atoms
what do London dispersion forces depend on?
size and shape

strongest between molecules of similar size and shape
polyatomic anions naming
depends on # of oxygens
oxyacid naming
ite --> ous

ate --> ic
Planck's constant (value, units)
h = 6.626 x 10^-34

Js = m^2kg/s
electronic charge
e = 1.6 x 10^-19 C
an atom ______ energy when accepting an electron. this is an _________ process. the atom become _______ stable.
releases
exothermic
more
excited state
when an atom absorbs energy, its electrons temporarily move to a higher energy level
electron configuration for transition metals
group 6 and group 11 borrow 1 electron from highest s subshell to fill d orbital half way or fully
atoms have ______ and _______ properties
particle and wave properties
photoelectric effect
electrons are emitted as photoelectrons when electromagnetic radiation hits a material
which group of elements have the highest ionization energy?
noble gases
first ionization energy
energy needed to remove an electron from a neutral atom in its gaseous state
second ionization energy
energy required to remove the second electron
is the first or second ionization energy greater? why?
second > first

b/c once the first electron is removed, the Zeff increases
which group of elements don't follow the electron affinity trend? why?
noble gases
b/c they're stable their electron affinity is endothermic
ionization energy
the energy needed to remove an electron from an atom in the gaseous state

left to right: increases
top to bottom: decreases
Why does ionization energy increase across a period?
the increasing Zeff makes it more difficult to remove an electron
Why does ionization energy decrease down a group?
outer electrons are farther from the nucleus and easier to remove
characteristics of metals (size, physical properties, state)
-large atoms; lose electrons to from positive ions
-easy electron movement gives metallic character (ductility, malleability, conductivity, luster)
-solid at room temp
characteristics of nonmetals
-tend to form anions
-lower melting point than metals b/c metals have strong metallic bonds
metalloids
Elements that have properties of both metals and nonmetals.
representative/main-group elements
Groups 1, 2, 13-18
common ions
group 1
alkali metals

-soft solids
-low density
-low melting point
-exist only as compounds in nature
group 2
alkaline earth metals

-harder, denser, high melting pt compared to alkali metals
-less reactive b/c full s orbital
group 14
-form 4 covalent bonds w/ nonmetals
-3rd period + can form 2 additional bonds w/ lewis bases
group 15
-form 3 covalent bonds
-3rd period + can form 2 additional bonds and can form a 6th bond w/ lewis bases
group 16
chalcogens/oxygen group

-oxygen = strong pi bonds

-sulfur = can form up to 6 bonds
group 17
halogens

-radioactively stable
-highly reactive
-diatomic states (Gas: F, Cl) (Liquid: Br) (Solid: I)
group 18
noble gases

-non-reactive
-found in nature as isolated atoms
-all gases at room temp
fail to complete the octet
Boron
Aluminium
Berylium
expanded octet
sulfur
phosphorous
chlorine
silicon
atomic radius
distance from nucleus to the outermost electron orbital

left to right: decrease
top to bottom: increase
Why does atomic radius increase down a group?
increasing number of energy levels
Why does atomic radius decrease across a period?
valence electrons are being added to the same energy level at the same time the nucleus is increasing in protons.

The increase in nuclear charge attracts the electrons more strongly, pulling them closer to the nucleus.
effective nuclear charge
the amount of positive charge that actually acts on an electron

left to right: increases
top to bottom: decreases
effective nuclear charge equation
Zeff = Z - S

Z = nuclear charge (# protons)
S = # core electrons
what's the relationship between effective nuclear charge and atomic radius?
inversely proportional
why does effective nuclear charge increase across a period?
the electrons are in the same energy level, so they don't experience significantly more shielding
Why does effective nuclear charge decrease down a group?
the number of energy levels increases, so there is a greater distance between the nucleus and the outermost orbital

there is also more shielding because shielding increases with more E levels
shielding effect
core electrons shield valence electrons from some of the nuclear charge
shielding increases with...
more energy levels
order of ion sizes. why?
cation < neutral < anion

as electrons are lost, Zeff increases, so electrons are pulled closer to the nucleus
isoelectric atoms
same number of electrons, different elemental identity

most negative = largest
most positive = smallest
electronegativity
tendency of an atom to attract electrons shared in a covalent bond

left to right: increases
top to bottom: decreases
Why does electronegativity increase across a period?
atoms are closer to filling their valence shell, so they really want more electrons
Why does electronegativity decrease down a group?
valence electrons are farther away from bonding atoms nucleus and harder to attract
electron affinity
willingness of an atom to accept an additional electron; the energy released when an electron is added to an atom

left to right: increases
top to bottom: decreases
Why does electron affinity increase across a period?
there's an increases nuclear attraction and desire for an electron
why does electron affinity decreases down a group?
electron is being added increasingly further away from the nucleus and can be easily removed
is Li paramagnetic or diamagnetic? why?
paramagnetic

b/c subsell isn't full
diamagnetic elements (electron pairing, spin alignment to magnetic field, reaction to magnets, effect on magnetic field lines)
-elements with no unpaired electrons, meaning subshells are completely filled
-antiparallel spins
-weakly repelled to magnets
-unresponsive to external magnetic fields
paramagnetic elements (electron pairing, spin alignment to magnetic field, reaction to magnets, effect on magnetic field lines)
-elements w/ unpaired electrons
-parallel spins
-attracted to magnets
-field bends toward material
work function
phi

minimum amount of energy needed to eject an electron from a metal
photoelectric effect equation
KE = max KE of emitted electron
hf = energy of photon
work function = energy to eject electron
alpha decay
when an atom releases an alpha particle
beta decay
breakdown of a neutron into a proton and an electron

electron gets expelled
positon emission
emission of a positron when a proton becomes a neutron
positron
a particle with the mass of an electron but a positive charge
mass number
A

protons + neutrons
atomic mass
A

protons + neutrons
binding energy
energy needed to break the nucleus into protons and neutrons

indicates stability of nucleus
isotopes
atoms with same atomic number (# protons), but different number of neutrons

atom name- mass number
isotopes are atoms of the same element that have different number of _______
neutrons
isotopes of the same elements have nearly identical _______ properties, but differ in their ________ properties
identical chemical properties (bonding, reactivity)

different physical properties (density, mass)
Aufbau Principle
each orbital in a shell must be subsequently filled before the next shell
hund's rule
each orbital is occupied by 1 electron before any orbital has 2 electrons
Pauli Exclusion Principle
no 2 electrons can have the same 4 quantum numbers
are smaller or larger atoms more polarizable?
larger
polarizability
ease with which the electron cloud can be disturbed
bohr atom
an atom is a nucleus surrounded by electrons in discrete electron shells
after beta decay, the mass number _______ and the atomic number _______
stays the same
increases by 1
electron capture
capture of an electron and the merging of an electron and proton to form a neutron
gamma decay
when an atom releases a gamma particle
atomic weight
the weighted average of the naturally occurring isotopes of an element
atomic number
Z

number of protons
quantum number: n
shell level of electron

principle quantum number

n= 1,2,3...
quantum number: l
shape of orbital

l = n-1
quantum number: ml
orbital 3D orientation

-l to +l
quantum number: ms
direction of spin

(+1/2 or -1/2)
number of total orbitals in a shell =
n^2
Heisenberg uncertainty principle
it is impossible to know exactly both the velocity and the position of a particle at the same time
emperical formula
simplest whole # ration of atoms in a compound
molecular formula
represents exact numbers of atoms
percent composition by mass
molecular weight of element / molecular weight compound x 100%
1 gram = ______ amu
1 gram = 6.022 x 10^23 amu
type of reaction? A + B --> AB
synthesis/combination

ex: Fe + S --> FeS
type of reaction? A + BC --> B + AC
single-replacement/displacement
type of reaction? AB + CD --> AC + BD
double-replacement or metathesis
type of reaction? AB --> A + B
decomposition
complete combustion reaction
hydrocarbon + oxygen --> carbon dioxide + water + heat
Incomplete combustion reaction
occurs with an insufficient oxygen supply

contains carbon monoxide reactant
limiting reactant
(mol A) x (mole ratio B: A)
faraday
1 faraday = the electric charge in 1 mol of electrons
path functions
heat, work

*often lowercase letters
state functions
enthalpy, temperature
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