final exam 1
Chemistry 177 with Kingston at Iowa State University
About this deck
By: Maggie Schildgen
Textbook:
Chemistry: The Central Science
Created: 2011-12-11
Size: 109 flashcards
Views: 58
Textbook:
Chemistry: The Central ScienceCreated: 2011-12-11
Size: 109 flashcards
Views: 58
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diatomic molecules
Br2, I2, N2, Cl2, H2, O2, F2
(brinclhof twins)
physical properties
observable without changing the substance
(ex. color, odor, density, mass, volume,etc.)
chemical properties
observe a change in the chemical structure
(ex. chemical reaction, combustion, heat given off, unexpected color change,etc.)
law of constant composition
same composition always, h20 is h20
law of multiple properties
same components can create different compounds and mixtures
intensive properties
properties that don't depend on the about of material/size of the sample
(ex. density--will stay the same whether its a 7 gram sample or a 700 gram sample)
extensive properties
properties that do depend on the size of the sample
(ex. mass, volume, heat given off,etc.)
density
density is a physical property of a substance that has units of mass/volume (g/mL); density of a substance will vary with changes in temperature and pressure; is used to distinguish pure substances
precision
all data points are near each other and in close proximity, not necessarily right on though
accuracy
not necessarily close to each other but dead on in the middle-near expected data collection range
temperature
measure of kinetic energy of the particles
SI units
1. length--meters
2. mass--kilograms
3. time--seconds
4. temperature--kelvin
5. amount--mole
6. electric current--amp
7. luminous intensity--candela
John Dalton's postulates
1. each element is composed of extremely small particles called atoms
2. all atoms of given element are identical to one another, atoms of different elements are different
3. a) atoms of an element are unchanged in a chemical reaction
b) atoms can be neither created or destroyed in a chemical reaction
atomic theory of matter
1. law of constant composition
2. law of multiple proportions
3. law of conservation of mass
"plum-pudding" model
developed by Thomson, cathode ray experiment--measured charge/mass ratio of electron
deflected cathode rays off of nucleus and electrons
Milikan
determined charge on electron with oil-drop experiment
rutherford
gold-foil experiment--scattered particles=space within the atoms, proposed idea of the nucleus and electron clouds
isotopes
same element but with different masses due to the different number of neutrons
mass number
number of protons + neutrons
atomic number
number of protons / electrons
weighted average atomic mass
multiple the isotope mass by the abundance percent (as a decimal) and divide by the number of isotopes
empirical formula
simplest form (reduced)
molecular formula
accurate counting (not reduced form)
covalent bonds
two non-metals, SHARING of electrons
ionic bonds
metal and a non-metal, TRANSFERRING of electrons
radio activity
1. beta rays- charge of -1
2. alpha rays- charge of +2
3. gamma rays- no charge
naming
"ic" i "ate" a poinson"ous" b"ite"
hj
(hypo- and per- are only for halogens)
combination reactions
2 or more substances react to make one product
decomposition reactions
one reactant and 2 or more products
combustion reaction
rapid and produce a flame
some reactant + O2-----> CO2 + H2O always!
oxidation reaction
also result in CO2 + H2O
formula weight
adding the masses of each atom on the equation
*don't forget to multiple each molecular weight by the coefficient
organic compounds
n=1 methane
n=2 ethane
n=3 propane
n=4 butane
n=5 pentane
atomic weight
total (sum) of the molar masses of each atom in the molecule
grams-->moles--->formula units
GRAMS<---use molar mass--->MOLES<---use avagadro's number--->FORMULA UNITS
mole ratio of a compound
MASS % ELEMENTS--->assume 100 gram sample--->GRAMS OF EACH ELEMENT--->use molar mass--->MOLES OF EACH ELEMENT--->calculate mole ratio--->EMPIRICAL FORMULA
whole number multiple
whole number multiple = molecular weight / empirical formula weight
given: grams of substance A; find: grams of substance B
GRAMS OF SUBSTANCE A--->use molar mass of A--->MOLES OF A--->use coefficients of A and B from balanced eqn.--->MOLES OF B--->use molar mass of B--->GRAMS OF SUBSTANCE B
percent yield
% yield = (actual yield / theoretic yield) * 100
STP
standard temperature and pressure
1 atm of pressure, 0 degrees Celsius, will be 22.4 L for volume
limiting reactant
find theoretical yield for each reactant, whichever is less is the limiting reactant--->all else is excess
molarity
concentration of a solution
M = moles / liters
electrolytes
dissociate into their ions when in water
weak: everything else pretty much
strong acids
HCL, HBr, HI, HNO3, H2SO4, HCLO4, HCLO3
oxidation reaction
loss of electrons by a substance
reduction reaction
gain of electrons by a substance
oxidation numbers
1. for an atom in elemental for the ox # is always 0
2. for any monatomic ion the ox # equals the ionic charge
3. non-metals usually have - ox #'s but can be +
(O2 is usually -2, hydrogen is usually +1, fluorine and halogens is usually -1)
re-dox reactions
at least 2 ox #'s must change in the reaction
atom oxidized---> ox # increase
atom reduced---> ox # decrease
displacement reactions
A + BX---> AX + B
reaction between a mental and either an acid or a metal salt (a.k.a. redox reactions)
dilution
solutions of lower concentration obtained by adding water
M1*V1 = M2*V2
titration
combing a solution where the solute concentration is NOT known with a reagent solution of known concentration
equivalence point
point at which stoichiometrically equivalent quantities are brought together
titration calculations
VOLUME KNOWN SOLUTION--->use M of known--->MOLES OF SOLUTE IN KNOWN--->use coefficients of balanced eqn.--->MOLES OF SOLUTE IN UNKNOWN--->use V of unknown--->M of unknown
heat
transfer of thermal energy between 2 objects/bodies at different temperatures
OR
the energy associated with a phase change
measures the temperature change relating to mass
temperature
a measure of the hotness or coldness of an object relative to a standard
OR
a measure of the random vibrations of atoms/molecules
energy
the capacity to do work
when energy causes an object to move it's called work
when energy causes an object to change temperatures it's called HEAT
law of conservation of energy
energy cannot be created or destroyed
energy of the universe is constant
internal energy of the system
the sum of PE + KE = E --->potential energy and kinetic energy
calculating heat
q = mass * specific heat * change in temp.
q~lost+ q~gained = 0
Change in heat = q~reaction / moles of limiting reagent
change in heat of the reaction
sum of the heat change in products - sumo heat change in reactants
work
the system is doing work in when W is - (negative)
work is done ON the system when W is + (positive)
W = -P * change in V
endothermic
when the system releases heat, q is negative
exothermic
when the system absorbs heat, q is positive
Bohr's hydrogen atom assumptions
1. electrons in an at ion can only occupy certain orbitals corresponding to energy levels
2. electrons in energy levels are stable, these do not emit radiation
3. electrons can absorb or emit energy only at certain frequencies or wavelengths that are "allowed"
calculating energy associated with level change
E =( -2.18*10^-19 J) * (1/nf^2 - 1/ni^2)
calculating wavelength
wavelength = h / mv
n--> principle number
main energy level
"shell"
n=1,2,3,4...(whole numbers)
l-->azimuthal
angular momentum
"orbital"
l = 0 S
l = 1 P
l = 2 D
l = 3 f
m_l--> magnetic quantum number
orientation of orbitals
l = 1 --> m_l = -1, 0, 1
l = 2 --> m_l = -2, -1, 0, 1, 2
etc.
m_s--> spin
either +1/2 or -1/2
Hun's rule
has to go to next "slot" in each orbital, same spin, unless its full
autbau' principle
needs to be stable, fill in progressive order
valence electrons
nu,ber of electrons in the HIGHEST level of the orbitals
even if its not 'last" in the electron configuration
pauli exclusion principle
no 2 electrons may have the same set of quantum numbers
ionization energy
energy needed to remove an electron
the smaller the atom the larger the ionization energy
easier to remove an electron thats paired up due to repulsion
electron affinity
energy change that occurs when an electron is added to an atom i the gaseous form
pretty much the ability of an atom to obtain an electron from another atom
paramagnetic
has unpaired electrons
diamagnetic
had NO unpaired electrons
electronegativity
atoms strongness of attraction to obtain an electron (sort of?)
increases as go across and as you go down on the periodic table
*in a lewis structure, atom witht eh least electronegativity is the central atom (expect ions are F and H)
formula charges
"break" the bonds on lewis structure and add up electrons, compare to original valence electrons
more than original = negative
less that original = positive
add up all of those to get total charge of over all molecule
octet rule
all electrons want 8 electrons in the outer shell
oxides of metals
H2O + salt?
always a basic solution
dipole moments
dipoles are the polar charges between
M = Q * r
where: M = Debye, Q = charge, r = distance
bond breaking and forming
forming = exothermic
breaking = endothermic
exceptions to the octet rule
1. odd # of valence electrons
2. less than octet of valence electrons to start with (ex. H)
3. more than the octet of electrons (pretty much anything with fluorine in it)
VSEPR
Valence Shell Electron Pair Repulsion theory
electron pairs (and unpaired) repose others and thus determine the shape of the molecule (ex. lone pair in H2O makes the shape bent, not linear)
hybridization
mixing of atomic orbitals to give molecular hybrid orbitals
sigma bonds--> head on collision of orbitals (single bonds)
pi bonds---> sideways collisions of orbitals (double or triple bonds)
molecular orbital theory
if waves interact consecutively, the resulting orbital is lower in energy; a bonding molecular orbital
bond order
bond order = 1/2 [#e-s bonding - #e-s nonbonding]
properties of gases
compressible
less dense
volume adjusts to container size
pressure
pressure = force / area ----> P = F / a
*F = ma (force = mass * acceleration)
1 atm
1 atm = 760 mmHg
1 atm = 14.7 PSI
1 atm = 760 torr
*1 mmHg = 1 torr
Boyle's law
when T and n are constant, P varies with 1/V
P1*V1 = P2*V2
Charle's law
when P and n are constant, V varies with T
V1/T1 = V2/T2
OR
P1/T1 = P2/T2
Avagdro's law
when T and P are constant, V varies with n
at STP any 1 mole of a gas will have a volume of 22.4 L
Ideal Gas Law
PV = nRT
d = (m*P)/(RT)
M = (dRT)/ (P)
partial pressure
P total = P1 + P2 + P3...
P1 = (nRT)/(V) or x*P total
--->X is the mole ratio
kinetic molecular theory
1. assumes particles have random direction of kinetic energy
2. volume/ space occupied by the molecules is insignificant compared to total volume
3. no attraction/ repulsion between molecules
4. energy is conserved
5. average KE varies at any given T, the average KE of a different gases will be the same
effusion
slow leak via a small whole
diffusion
slow spreading of molecules throughout the room
(ex. scented spray)
r1/r2 = (square root) m2/m1 = T2/T1
intermolecular forces
1. dipole-dipole
~ polar molecules
2. ion- dipole force
3. london-dispersion force
*only force for non-polar!
4. hydrogen bonding
hydrogen bonding
*special kind of dipole-dipole bonding
1. need H
2. H should be attached to F, O, or N (electronegative atoms)
3. should have attraction with F, O, or N
heating curves
temp increases when intermolecular forces break
graph of temp to pressure- atm of heat change relationship
phase equilibrium
when 2 phases exist at once
triple point
all 3 phases are at equilibrium
phase changes
S--->G sublimation
G--->S deposition
L--->G evaporation
G--->L condensation
S--->L fusion
L--->S freezing
normal freezing point
temp at which a substance freezes at 1 atm of pressure
normal boiling point
temp at which a substance melts at 1 atm of pressure
density: pressure relationship
as density increases, pressure decreases
About this deck
By: Maggie Schildgen
Textbook: Chemistry: The Central Science
Created: 2011-12-11
Size: 109 flashcards
Views: 58
Textbook:
Chemistry: The Central ScienceCreated: 2011-12-11
Size: 109 flashcards
Views: 58
About StudyBlue
STUDYBLUE makes things that make you better at school.
Things like online flashcards with photos and audio.
Things like personalized quizzes and friendly reminders about when (and what) to study next.
Think of it as a digital backpack™: access to all of your study materials online and on your phone.
STUDYBLUE exists to make studying efficient and effective for every student, for free. Join us.
“I have been getting MUCH better grades on all my tests for school. Flash cards, notes, and quizzes are great on here. Thanks!”
Kathy
Kathy