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Fichas del conjunto (186)
- 1What phenomenon demonstrates the wave theory of light?interference phenomenon (constructive/destructive waves)
- 2How could one observe the interferencWe phenomenon?using the two-slit experiment.
- 3T/F: light is not a form of electromagnetic radiation.F. it is . like are microwaves, Infrared, UV, x rays and so on.
- 4What does an electromagnetic wave consist ofelectric-field component and a mutually perpendicular magnetic-field component oscillating in space with a frequency,v.
- 5What is the difference in oscillation for polarized and unpolarized light?polarized- electric and magnetic components can oscillate only within the two fixed planes (xy and xz)
unpolarized- the two components can and do rotate about th ex axis. - 6What was the problem with the wave theory?emission of radion by solids as a function of temperature gave curves that could not b e explained by the wave theory or by the laws of thermodynamics.
- 7T/F. Not all bodies above absolute zero emit radiation over a range of wavelengths.False. all do.
- 8Why is a black body defined to be a perfect absorber and perfect emitter of radiation?because it absorbs all radiation that strikes it. and because it is in equilibrium with its surruoundings, a blackbody is also a perfect emitter of radiation.
- 9how did planck solve the mystery of the blackbody radiation curves?-proposed that radiant energy could not have any arbitrary value;instead, the energy could be emitted only in small, discrete amounts called quanta.
- 10What was the classical approach to blackbody radiation?assumed that the radiant energy emitted by a collection of oscillators in a solid could have any energy value within a continuous range.
- predicted radiation profile that has no maximum and goes to infinite intensity at a very short wavelength (ultraviolet catastrophe) . - 11What is the relationship between energy of emitted radiation and frequency of the oscillator ? what's the equation?energy , E, is proportional to the frequency v of the oscillator:
E=hv - 12The wave theory relates energy of radiation proportional to the square of the amplitude. Thus, energy is related to frequency not intensity of radiation. T/FF. energy is related to intensity of radiation not frequency.
- 13when light at certain frequency shines on a clean metal surface, electrons are ejected from the metal. what is found experimentally?3 things What does this contradict?1. # of electrons ejected is proportional to the intensity of light
2. the KE of the ejected electron is proportional to the frequency of incident light
3. no electrons can be ejected if the frequency of the light is lower than a certain value-threshold frequency
#2 is contradicted by the wave theory of light which says that energy is related to the intensity not frequency of radiation - 14How did einstein solve the contradiction of experimental KE of ejected electron and the wave theory of light? what is the equationhe assumed that light consisted of particles called light quanta (photons) of energy hv (v is frequency of light).
-light striking metal can be thought of as collisions between photons and electrons.
hv=phi + 1/2m(e)v^2 - 15The rydberg formula doesn't explain what?origin of spectral lines.
- 16Bohr's theory made use of what other theories?classical physics and planck's quantum theory.
- 17What does Bohr's theory state about the H- emission spectrum? what does this mean?He believed that the electron in the H-atom moves around the nucleus only in certain allowed circular orbits.
- meaning that its energies are quantized and we can speak of the electron being in a particular energy level corresponding to a specific orbit. - 18what does the negative in Bohr's equation mean?what does it tell you about the states?that the allowed energies of the electron are less than the case in whi h the electron and the proton are infinitely spearated- assigned to be zero.
-the more negative En is, the stronger the attraction between the electron and proton.
-thus more stable stat e is one given by n=1- ground state. excited state is one for which n>or= 2 - 19According to de Broglie, an electron bound to the nucleus behaves like what?a standing wave- plucking a guitar.
- 20T/F de Broglie's equation is important for only submacroscopic objects.F. submicroscopic particles- like electrons, atoms, and molecules.
- 21T/F the greater the frequency of vibration, the shorter the wavelength of the standing wave and the greater the number of nodes.T
- 22If electron does behave like a standing wave in the H atom, the length of the wave must fit what?the circumference of the orbit exactly. otherwise the wave would partially cancel itself on each successive orbit.
- 23What happens when the amplitude of the wave is reduced to 0 ? (for H atom emission spectrum)means- wave can't exist. So the wave properties of the electron restrict the orbits it can occupy and thus the energies it can possess.
- 24What property of the electron is useful in electron microscope ?the wavelike behavior of electrons.
- 25T/F . The greater the frequency of vibration, the greater the wavelenght of the standing wave and the greater the number of nodes.F. Greater frequency of vibration, shorter wavelength of standing wave and greater number of nodes.
- 26T/F to determine macroscopic particle's position and momentum is just as hard as a large particle.F. small particles' inaccuracies due to interactions of observation in measuring position and momentum are negligible.
- so we can accurately determine the position and momentum of a macroscopic object simultaneously. - 27T/F Planck's constant is only important when dealing with particles on a macroscopic level.F. atomic level.
- 28T/F Since uncertainity principle could be written in terms of energy and time, we can measure the (kinetic) energy of a particle with absolute precision (dE=0).F. we cannot in a finite span of time.
- 29Why was Bohr's theory inadequate?it couldn't account for the emission spectra of more complex atoms (like helium) or for the behavior of atoms in a magnetic field.
- notion that electron is circling the nucleus in a defined orbital is inconsistent with the uncertainty principle. - 30What is the main difference between the classical mechanics' energy equation and shrodinger's equation?T in classical mechanics is replaced with the kinetic-energy operator in the schrodinger's equation.
- 31T/F . s electron is more penetrating than a p electron.T. thus 2 p is more shielded from the nucleus by the 2 s electron
- 32T/F energy of 2p electron is lower than 2s because it is less shielded from nucleus.F. higher energy than 2s and is more shielded from the nucleus by the 2s
- 33Does the H-atom have shielding?no. because it only has one electron.
- 34What part of the wave function determines the shapes of orbitals and which one the size?angular part determines the shape of orbitals while the radial part determines the size of orbital.
- 35What is the 4th quatum number and what is it analogous to?ms. spin of an electron. analogous to ml
- 36What is the geometry of a s orbital?it is spherically symmetric because it contains only a constant
- 37What is the geometry of a p orbital?doesn't have spherical symmetry because p orbitals depend on theta and phi.
- 38T/F All p orbitals have the same energy.because they are equivalent except orientations so all 3 p-orbitals have the same energy
- 39T/F- in the absence of a magnetic field, the energy of the electron is the same whether ms=+1/2 or ms=-1/2.T
- 40What is the pauli exclusion principlestates that no two electrons in an atom may have the same four quantum numbers.
-meaning total wave function of the electrons must change its sign when any two electrons are exchanged. - 41What does Hund's rule state?that when more than one electron enters a set of degenerate levels, the most stable arrangement is the one with the greatest number of parallel spins.
- 42What is the physical interpretation of the Hund's rule?that the pauli exclusion principle forbids two electrons with parallel spins in an atom to approach each other closely so placing them in different orbitals decreases the electrostatic repulsion.
- 43What is the equation for the velocity of a wave?v=^v (lambda* frequency of wave)
- 44What is the einstein's photoelectric equation? What does it tell us about bout the experimental observations?hv=theta+KE
- # of photons increases with intensity of light, so more electrons are ejected at higher intensities
-energy of the photons increases with the frequency of light so that electrons ejected at higher frequencies will also possess higher KE - 45Under what conditions do atoms emit electromagnetic radiation that has frequency characteristics?When atoms are subjected to high temperatures or electrical discharge
- 46What does Born-Oppenheimer approximiation state?That nuclei are much heaveir than electrons, thus they remain stationary.
- 47What is the formal charge equation?valence electrons-# of nonbonding electrons- 1/2 (number of bonding electrons)
- 48What happens to the PE as the atoms move closer?As the two H atoms move toward each other, the PE changes.
- when they are far apart , PE =0 and the wave function describing the two atoms is a product o fthe individual wave functions
w=w(1)w(2) - 49What is the improved equation for the wave function of electrons and atoms interacting? why the improvement?Because electron 2 could be on top of atom 1 and vice versa, improved wave functions i given by:
w=wa(1)wb(2)+wa(2)wb(1) - 50T/F. VB theory is good for excited state only.F. ground state only.
- 51What are the three simplest carbon molecules that represent the three types of chemical bonds of stable carbon?methane
ethylene
acetylene - 52What does the VB theory explain and what does it fail to explain?gives # of bonds formed, bond lengths, bond energies, but fails to explain molecular geometry
- 53What should be considered when trying to understand the ionic character of molecules and molecular geometry?electronegativity and dipole moment
- 54T/F . molecules that possess a permanent dipole moment are called non-polar molecules.F. polar molecules
- 55Can the dipole moment measurements be used to obtain bond length and angles? why or why not?no. because the value is given as a product of two quantities (charge and distance)
- 56What are dipole moment measurements good for?for determining the symmetry of a molecule, but not much in charge separation because it is difficult to estimate accurately.
- 57Why is CO2 linear and not bent?because it does not possess a permanent dipole moment.
- 58What is the correlation between electronegativity difference and percent ionic character?Positive correlation. purely covalent molecule has 0% ionic character. purely ionic compound has 100% ionic character.
- 59What does the Molecular Orbital (MO) theory assume?that two atomic orbitals merge to become molecular orbitals.
- 60How does the sigma and sigma star orbitals arise?from the linear combination of the atomic orbitals
- 61What do the sigma and sigma star orbitals correspond to ?potential-energy curves with and without a minimum (respectively)
- 62What are the lowest energy level molecular orbitals?sigma 2s and sigma 2s* because the 2s atomic orbitals lie below the 2p atomic orbitals.
- 63Why is sigma2s falling and sigma2p rising in energy during the MO energy diagram?because s-p mixing affects the energies of sigma2s and sigma2p molecular orbitals.
- 64T/F . Hybrid atomic orbitals are inter-atomic.F. they are intra-atomic. mix atomic orbitals from same atom .
- 65T/F Molecular orbitals are inter-atomic.T. from different atoms.
- 66What are the three criteria for forming MO?1. must have non-zero overlap
2. combined atomic orbitals must have same symmetry
3. from N atomic orbitals we can make N molecular orbitals. - 67Tunneling through activation barriers in reactions is most important for light atoms such as:proton transfer
electron transfer - 68What is one indication of tunneling in a reaction?Non-Arrhenius
- 69Probability of finding a particle at a specific location is dependent on what?energy and position
- 70What are the three properties of wave functions?1. it is not a mathematical description of the wave properties
2. does not have any physical meaning by itself
3. probability of particle is given between x and x+dx - 71T/F the classical view works on the atomical scale but not the macroscopic scale.F. on the macroscopic scale it works.
- 72T/F . antibonding / destructive interaction is higher in energy.T.
- 73What are coordination compounds?a metal ion is coordinated with number of ligands.
- 74What is metal corridnation?the removal of 2 of the s electrons on the metal to leave it having a charge. and use the d-orbitals to interact with the lone electrons in a way that we get a bonding interaction.
- 75What is metal coordination driven by?- geometry and ligand repulsion.
- 76What is the first thing to consider when you have a metal with two ligands?to get the ligands far apart as possible from each other. because of the repulsion from non-bonding electrons.
- 77What is the most default position for 3 ligands?trigonal planar- 120 degrees between ligands.
- 78What is the best way to get ligands as far apart from each other as possible when you have 4 ligands?put a 109.2 degree between them (tetrahedral coordination)
- sometimes - square planar (outlier)- when ligands are overwritting their chemistry - 79What are the rules for transition metals?1. when filling in orbitals 1s,2s,3s,3p,4s,3d
2. removing electrons from a neutral atom, you take out first from s orbital. (because there are 2 electrons in the s orbital, it is common to pick up the positive charge ) then d orbitals.
3. c - 80How can we use the crystal field theory to describe metal and ligand interactions?1. treat ligands as negative point charges
2. consider electrostatic effect on metal orbitals. - 81what is the ligand field theory?form of molecular orbital theory.
how we form molecular orbitals from the energy of d orbitals. - 82What does the crystal field theory assume?1. that there will be electrostatic interactions between the lone pairs
2. ignore bonding and look at what does it do to the energies of the d orbitals to have lone pairs pointing at it in various configuration - 83why do z2 and x2-y2 go up while xy,xz,yz go down? for octahedral .because of crystal field splitting (delta)
- 84What are the strong and weak ligands?..
- 85What is the equation of the rate in the form of disappearance and appearance ?rate=-d[R]/dt
rate=dP/dt - 86T/F quanitity of interest is the rate over a certain time interval when looking at the rate equations.F. this is only an average quanitity whose vale depends on the certain value of dt.
* rather we are interested in the instantaneous rate. - 87What are the units of reaction rates usually?[x]/time
- 88T/F reaction rate could be expressed as rate proportional to [A]*[B]^ ~ rate= k[A]*[B]^NOT ALWAYS.
known as the rate law. - 89T/F rate constant is dependent on the [reactants] ONLY.F. only affected by temperature .
- 90What does the rate law help us to define?*the order of a reaction,
*concentrations of reactants at any time during the course of a reaction. - 91What are all the things could the rate be effected by?r=k'thetaA
*fraction of metal surface covered by absorbed ammonia molecules.
A - total catalyst surface area. - 92T/F First order reaction is independent of the [reactant] when finding the rate.F. is dependent only on the concetration. so k= s^-1
- 93What kind of decrease in [reactant] do we see in a first order reaction?exponential decrease which could be seen with the graph of the integrated form of the rate law. ln[a]/[a]i=-kt
- 94T/F half life of a second order reaction is independent of [r]i?F. halflife of first order reaction is independent of initial concentration
- 95What assumptions are made when looking at a second order reaction with two different reactants?1. [a]=[b], or
2. [a]<<[b] - 96What is one well known example of a second-order reaction? first order reaction?second- renaturation of DNA in solution
first- radioactive decay - 97What are the 4 common ways to determine reaction order?1. integration method
2. differential method
3. half-life method
4. isolation method - 98How does the integration approach work to find reaction order?measure concentrations of reactants at various time intervals of a reaction and substitute them into known equations for different reaction orders.
*equation that gives the most constant value of the rate constant for a series is best answer - 99What is the approach to finding reaction order through half-life method?see how the half-life depends on initial cnocentration.
especially useful for first order reactions - 100What assumption can we make when we have an activated molecule (A*) when deriving the rate of the reaction?Because A* is an excited state,it has little stability and short lifetime.
it's concentration in the gas phase is not only low but probably fairly constant.
- so we can apply the steady state approximation (where d[A*]/dt =0) - 101what do all three-body collisions include as one of their reactants?Nitric Oxide
(2NO + X2 > 2NOX)
X=Cl, Br, or I - 102How do you develop equilibrium constant K?at equilibrium reversible reaction: d[A]/dt=0
so, k1[A]=k-1[B]
[B]/[A]=k1/k-1=K - 103what is the collision theory based on?kinetics theory of gases.
- applies to bimolecular reactions in the gas phase - 104in the collision theory equation for binary collisions , A is what? and depends on what?A is the frequency factor which is temperature dependent , but in practice it is treated as independent of temperature when calculating Ea.
- 105T/F . collision theory predicts value of the rate constant accurately for reactions that involve subatomic species or simple molecules if the Ea is known. Is it true for complex molecules? How do you account for discrepencies?F. of atomic species or simple molecules if the Ea is known.
But for complex molecules, rate constants tend be smaller than the predicted because the simple kinetic theory counts every sufficiently energetic collision as an effective one. But in reality molecules may not even approach each other the right way, even if energy is available . to correct for this a P (probility or steric factor) takes into account the fact that in a colilision complex, molecules must be properly oriented. - 106What is a drawback of the collision theory?state 21. because it is based on Kinetic theory of gases, it assumes the reacting species are hard spheres and ignores structures of molecules.
2. without quantum mechanics, we can't use collision theory to calculate Ea. - 107Why was the transition- state theory developed other than the drawbacks of collision theory?list 21. it provides greater insight into details of reaction on the molecular scale.
2. it enables us to calculate the rate constant with more accuracy - 108What is the first assumption made by the transition state theory that is different from collision theory ?1. reactants are ALWAYS in equilibrium with TS
- 109T/F reduction in Ea by the action of a catalyst would lower the rate constant.F. enhances the rate constant
- 110T/F rate is always proportional to the total concentration of the enzyme.T
- 111When [s]<>Ks what is the reaction order?v=k2[E][S]/Ks+[S]
2nd (first in [E] and first in [S])
* first in [E],0 in [S] - 112When is the only time Km=Ks?when k-1>>k2
- 113When can we not calculate the turnover #?if the purity of the enzyme or the number of active sites per molecule is unknown
-instead use specific activity (SA/mg of protein) - 114When can we measure the turnover number ?when we can measure the rate under saturating substrate conditions ([S]>>Km)
- 115What is the characteristic of a competitive inhibition?both the substrate and the inhibitor compete for the same active site
-only the ES complex leads to production formation - 116What is the defining characteristic of noncompetitive inhibition?the inhibitor binds to a site other than the active site.
-ESI complex doesn't lead to product formation - 117what is the defining characteristic of uncompetitive inhibition?inhibitor binds only to the ES complex.
-ESI complex doesn't lead to proudct formation - 118what is a study of spectroscopy ?interaction between electromagnetic radiation and matter
- detailed info about structure, bonding, various intra-inter molecular processes, can be obtained from the analysis of atomic and molecular spectra. - 119what are the units for wavelength?meters
- 120frequency is measured in what units?s-1 or Hz
- 121T/F Energy is indirectly proportional to wavenumber and frequency. when talking about wavenumberF. Directly proportional.
frequencies are too high, so impractical to use - 122the natural line width of a spectral line is a consequence of what?the heisenberg uncertainty principle
- 123What does dEdt>/ h/4pi mean?the longer it takes to measure the energy of a system in that state (dt large), the more accurately this energy can be determined (dE small)
- 124the natural width of the spectral line could be influenced by what?no external parameters.
- 125T/F the rate of transition from higher to lower stat is ONLY proportional to the number of molecules in low state.F. proportional to the number of molecules in low state if transition is from low to high state.
(Nmn)
and to radiation density p(v) - 126What are the two equations that einstein came up with when talking about transition states due to frequency? * what must be satisfied for Bnm?that Nmn=BmnNmp(v) is when low to high.
or Nnm=BnmNnp(v) when an excited molecule goes to the lower state.
*Bnm=Bmn. only then could transition stimulate shift from excited state. - 127what are the two types of forbiddin transitions when looking at selection rules?Spin forbidden,
symmetry forbidden - 128What are some characteristics of the spin forbidding transitions?List 2 and what they mean.1. involve change in spin multiplicity given by 2S+1
* gives us the number of different ways in which the unpaired spins can line up in an external magnetic field.
2.rule is that spin multiplicity must not change in a transition , we must have dS=0
ex: singlet to a doublet transition is forbidden. - 129What are the characteristics of Symmetry forbidden transitions ?1. transition dipole moment is involved- quantum measure of intensity of a transition.
2. function must be even for an allowed transition because mu depends only on the first power of the coordinates and is therefore odd.
ex: 1s > 2s foribidden.
1s> 2p allowed. because charge distriubtion is dipolar.
3. we can generalize these observations using selection rule dl=+-1 - 130What is one way to increase signal to noise ratio?by signal averaging- by repeatedly recording the same spectrum and adding the signals.
ex: if we average a spectrum N times, intensity will increase by a factor of N, and noise will increase by a factor of sqrtN.
-so signal to noise ratio will increase by N/sqrt(N) or sqrt(N) times. - 131Microwave spectroscopy is concerned with what kind of motion?rotational motion of molecules.
- uses reduced mass to treat the rotation of the molecule as a single particle of mass mu moving in a circle of radius r - 132Why are polar molecules microwave active while the non-polar molecules are not?nonpolar molecules- because they cannot interact with the electric field component of the radiation.
-while, polar molecules- because of their interaction between a dipole and an oscillating electric field from the electromagnetic wave causes it to be active. - 133T/F . Microwave spectroscopy applies only to molecules in the gas phase. why?T. because the frequency of molecular collisions in a solution are much greater than the frequency of molecular rotation.
- so molecules cannot execute full rotational motion and thus have no microwave spectra that can be obtained. - 134What is Infrared spectroscopy concerned with?vibrational motion of molecules.
- - 135what kind of electric dipole moment should you have to absorb IR radiation or to be IR active?du/dr > 0
electric dipole moment must change with bond lenght during a vibration. - 136T/F vibrational energies are quantized?T. because of the schrodinger equation for the harmonic oscillator.
- the lowest vibrational energy (v=0) is not 0 because it is 1/2hv according to the equation.
Evib=(v+1/2)hv - 137T/F molecules don't behave exactly like harmonic osccillators. Explain. what happens to spacing between vibrational levels?T. for ex: as r increases, the chemical bond weakens. eventually dissociation takes place.
- schrodinger equation for the harmonic oscillator gets rewritten :
Evib=(v+1/2)hv-x(v+1/2)2hv
-spacing between successive levels of vibration decreases with increasing v- due to anharmonic character - 138What does the Franck-Condon princple state?that because it takes much more time for a molecule to execute a vibration than it does for an electronic transition, the nuclei do not alter their positions during an electronic transition.
-so the most probable transitions are those for which the internuclear distance remains unchanged. - 139What do you see in the electronic spectra of diatomic molecules in the gas phase?both vibrational bands and rotational fine structure
- 140What does it mean that some nuclei have spinning motion?that there is a magnetic moment associated with them.
nuclear spin, I, may have values like:
0,1/2,1,3/2,2...
0 meaning no spin - 141The energy of a given spin state, Ei, is directly proportional to what?the value of mi and the magnetic field strength (Bo)
Ei=-miBo(yh/2pi) - 142What is the selection rule for nuclear spin energy-level transitions?dmi=+-1
- 143What governs the sensitivity of NMR?because it is a branch of absorption spectroscopy , governed by Boltzmann distribution
- 144Having a large shielding of nucleus means what for sigma constant and resonance frequency?larger sigma constant
lower resonance frequency
and the farther to the right it will appear in an NMR spectrum - 145What is the difference between thermodynamics? Mechanism? and kinetics?thermodynamics (dG is how likely it is for the reaction to happen.
-mechanics is what route is taken
- kinetics is how fast the route is - 146When does kinetics quantify the rate of a reaction?before equilibrium is reached
- 147how do we express the rate of a reaction?either the decrease of reactants or increase in product concentration as a function of time.
- 148T/F the rate has to be proportional to reactants raised to some power.F. doesn't have to be.
ex: v=k[A][B] - 149What does the overall reaction specify? how is this different from the mechanism-specifies reactants and products (amounts and energies)
- mechanism proposes elemantary steps in the reaction - 150T/F the overall reaction cannot derive the rate law.T. it can suggest a rate law.
mechanisms could help derive a rate law
v=k[A][B] - 151T/F experimental data from experimental observations could support or refute a mechanism.T. just can't prove a mechanism.
- 152What is the geometry of a molecule with Coordination Number (CN) of 2,3,4?2- linear (180)
3-trigonal planar(120)
4-square planar(90) - 153What is the geometry of molecules with CN of 4,5,6?4-tetrahedral (109,28)
5-trigonal bipyramidal (120,90)
6-Octahedral (90) - 154why are d5 and d10 configuration more preferred?because their half filled and full filled arrangements give extra stability.
- 155What three theories explain the bonding in coordination compounds' color, magnetic properties, and other characteristics ?Crystal field theory
molecular orbital theory
valence bond theory - 156What is the difference in the d orbital energy levels when metal is surrounded by ligands or not.?when alone- metal has all same energy regardless of their orientations
when ligands are present- not the case - 157what are the two types of interactions in the crystal field theory?1. attraction- between metal cation and negatively charged ligands (Cl-) or negative ends of polar ligands (H2O)
2. repulsion between valence electrons of the metal and the lone pair on the ligands. - 158T/F dx2-y2 and dz2 orbitals have lower energy than dxy,dyz,dxz.F. higher energy because electrons reside in orbitals experience a greater repulsion from the ligands than electrons in dxy.
- 159How can you check if a ligand is strong or weak field ?By measuring delta. larger delta means strong-field ligand.
d=hc/lambda - 160What does understanding strength of ligands help us learn ?optical and magnetic properties of complex ions.
- 161what kind of delta would a high spin complex result?small delta.
- 162What is the difference in the tetrahedral compared to the octahedral?it is switched. now dxy,dyz,and dxz orbitals are more closely directed at the ligands, so have higher energy than dx2-y2 and dz2
- 163what is the splitting pattern for Square planar compared to tetrahedral and octahedral?-they don't differentiate the d orbitals as much as the ligands in octahedral, the crystal field splitting is smaller.
- so , most tetrahedral complexes are high -spin complexes. - 164What is the downside of CFT? (crystal field theory?)it ignores covalent character of metal-ligand bonds. and only electrostatic interactions.
- 165What will the characteristics be for an octahedral molecule when using the MO theory?-dx2-dy2 and dz2 orbitals point at th eligands so they form sigma molecular orbitals with ligand lone pair orbitals.
-dxy,dyz,dxz orbitals will be the nonbonding molecular orbitals. - 166what is another advantage of MO theory that the Crystal field theory can't explain?the pi bonding interactions between ligand and metal ion.
- 167What do the MO and VB theories state briefly?VB- assumes that the electrons in a molecule occupy atomic orbitals of the individual atoms
MO- assumes formation of moelcular orbtials from atomic orbitals - 168What is the wave function for the molecular orbitals?function(sigma)=N(functionA+functionB)
function (simga*)=N(functionA-functionB) - 169A bond order of 0 or - means what?that the bond has no stability and molecule cannot exist.
- 170T/F the uncertainity in energy shows up as the width of the spectral line.T- called the natural line width because it is inherent in the system and cannot be influenced by external parameters.
- 171What does the natural line widths depend on?the type of transition. for instance, rotational energy levels gives a lower line width than one in electronic excited state.
- 172Explain the doppler effect. What equation is used? What could effect the doppler effect?one of the factors that can broden the lines.
-when radiation is emitted, its frequency depends on the velocity of the atom or molecule relative to the detector
v=vo(1+-v/c)
- doppler effect increases with temperature because there is larger spread in molecular speeds. - 173What is the pressure, collisional , effect on broadening?molecular collisions can deactivate excited states, thus shortening lifetimes.
liquid state has broader lines compared to vapor . - 174what dtao (dt) represent in the transition dipole moment?volume element dt=dxdydz
- 175what does the rotational constant equal to in the schrodinger equation for rotational envery equation?B= h/8p2I
- 176what equation is used to determine the spin multiplicity for the spin forbidden rule?2S+1
0 unpaired e- > 0 electron spin
2 unpaired e- > 1 electron spin - 177What is the formula for non-linear molecule and linear molecules when looking at normal vibrational modes?non-linear : 3N-6
linear: 3N-5 - 178T/F a molecule with largest mass will have the highest fundamental frequency of vibration.F. smalles mass will have highest frequency of vibration.
v=1/2pi (sqrt(k/u)) - 179What is the formule to find radial nodes?n-1-L
(L=0 for s, 1 for p, 2 for d) - 180what is the formula to find angular nodes?n-1
- 181When could the pre-equilibrium condition be applied ?when intermediate is in equilibrium with reactants.
- when k-1 >>k2 - 182T/F the eryng equation assumes that reactants are not in equilibrium with TS.F. it assumes they are.
- 183The Eryng equation describes the contribution of what two factors to the rate constant?entropy and enthalpy
- 184T/F The Eryng equation accounts for the Arrhenius behavior.T.
- 185What is the case with k1 and k2 when you have a steady state situation?k1<
- 186When interested in resonance, what does the MO and VB emphasize?MO- empahsizes electron delocalization
VB- emphasizes electron pair bond.