# Shared Flashcard Set

## Details

PChem Chapter 1 Learning objectives
Learning Objectives
45
Chemistry
09/29/2013

Term
 Describe the phenomenon of black body radiation
Definition
 As an object is heated there is a shift from red->white->Blue as e/m goes from low frequencies to high frequencies
Term
 Explain what is meant by ultraviolet catastrophe
Definition
 a prediction by Rayleigh-Jeans Law that as temp increase the radiant energy density should diverge at ν^2 and enter the uv region
Term
 Explain the relevance of the Rayleigh-Jeans law
Definition
 a classical physics approach at relating intensity and frequency of blackbody radiation to temp
Term
 Explain the assumption Planck made to derive the distribution law
Definition
 Assumption was that the energy oscillators where discrete and proportional to an integer multiple of frequency E-nhν. This hold true for all Temp and ν if h=Planck's constant
Term
 Describe the agreement btwn the Planck distribution law and experimental data of blackbody radiation
Definition
 Planck's distribution for black body radiation was in agreement w/ experimental data at all temps and ν if h = Planck's constant
Term
 [image]
Definition
 Rayleigh-jeans Law
Term
 [image]
Definition
 Planck's distribution Law
Term
 [image]
Definition
 Wien displacement Law
Term
 [image]
Definition
 the alt Wein displacement law
Term
 Describe what what wein's displacement says
Definition
 Relates the max wavelength from an e/m distribution emitted from a black body to temperature
Term
 How does weins law provide evidence for plancks law?
Definition
 Provides an empirical relation to plancks law for temp and wavelength if h=plancks constant
Term
 How was Planck's law view by his contemporaries
Definition
 They believed his assumption was an arbitrary deviation and that there should be something that obeyed classical physics
Term
 What was the Significance of Planck's assumption to quantum mech
Definition
 Energy was quantized
Term
 Describe the photo electric effect
Definition
 Is the ejection of an electron from the surface of a metal by a photon that has a frequency exceeding the threshold frequency of the metals work function
Term
 What are the 3 experimental observations for the photoelectric effect
Definition
 1)KE of ejected electron is independent of radiation intensity2)There is a min threshold frequency need to eject an electron3)Above threshold frequency, electron KE varies linearly
Term
 Define threshold frequency
Definition
 min frequency required to eject electron from surface of metal
Term
 Define threshold wavelength
Definition
 min wavelength required to eject electron from surface of metal
Term
 Define work function
Definition
 Analogous to ionization energy. Min amount of energy required by photon to eject electron
Term
 Describe Einstein’s explanation of the photoelectric effect
Definition
 Radiation exists in small packets of energy called photons. The KE of ejected electron is equal to the energy of the photon minus the min energy to remove electron
Term
 Identify Einstein's key equation
Definition
 E=hν
Term
 Explain how the value of Planck’s constant from photoelectric effect experiments compared to the value of Planck’s constant from blackbody radiation experiments
Definition
 The value of Planck's constant in both cases equaled that of Planck's constant from blackbody radiation.
Term
 Explain the significance of plancks constant to the development of quantum mechanics.
Definition
 Determined energy was quantized, which was significat to the development of quantum mech
Term
 Qualitatively describe the appearance of hydrogen emission spectra and how they are obtained.
Definition
 Subjecting hydrogen to high temp or electric discharge causes each atom to emit electromagnetic radiation of characteristic frequencies
Term
 Explain what a line “series” is in an emission spectrum
Definition
 The lines in an emission spectrum consist of only discrete frequencies.
Term
 how are the lines in a series emission spectra related?
Definition
 The lines in each series are related by an n quantum # that an excited eclecton relaxes to
Term
 how are the lines in different series emission spectra different?
Definition
 The difference for each series is what quantum state the electron relaxes to.Lymann n=1Balmer n=2Paschen n=3Brackett n=4
Term
 [image]
Definition
 Balmer formula
Term
 [image]
Definition
 Rydberg formula
Term
 State the Ritz combination rule
Definition
 Stater that all observed spectra lines for all atoms can be expressed as a difference of terms
Term
 Describe what is meant by “the wave-particle duality of light”.
Definition
 Mean that a photon of light has both wave properties (ex. diffraction) and particle properties (ex. photoelectric effect)
Term
 Describe de Broglie’s idea about wave-particle duality and matter.
Definition
 de Broglie postulated that if light had wave particle properties, matter should also exhibit wave-particle duality
Term
 Describe the classical diffraction pattern exhibited by x-rays and electrons and how it relates to the concept of wave-particleduality.
Definition
 Electrons exhibit a wavelength similar to that of x-rays. In both instances, when the wave interacts w/ an atom in a lattice, the wave front propagate around it exhibiting the same light and dark interference patterns. this experiment demonstrates the wave nature of electrons
Term
 Identify the de Broglie equation.
Definition
 λ=h/p
Term
 Define the de Broglie wavelength.
Definition
 The de Broglie wavelength is equal to planck's constant divided by the momentum of a particle
Term
 Describe the Bohr model of the atom
Definition
 Is the theory that explains the hydrogen atomic spectrum
Term
 Identify the two forces on the electron that are in balance
Definition
 Coulomb force and centripetal force
Term
 State Bohr’s two nonclassical assumptions.
Definition
 1) There are stationary electron orbitals2) The de Broglie wave of an electron must be in phase after a complete revolution
Term
 Define “ground-state energy”
Definition
 The lowest energy electron configuration of an atom
Term
 Define excited state
Definition
 An electron configuration of an atom other than the lowest energy state
Term
 Explain how the energy states are considered “bound states
Definition
 The electron is bound in the atom and in order to get an electron from n=1 to n=infinity requires energy
Term
 Draw the transition of the different hydrogen emission series on the energy level diagram
Definition
 [image]
Term
 [image]
Definition
 the equation for the radius of the bohr orbit
Term
 [image]
Definition
 the equation for energy of electron
Term
 Describe the problem encountered in trying to measure the position of an electron with light.
Definition
 The photon used to locate the electron imparts a momentum to the electron while locating it. As a result, you know the location of the electron w/ in the width of the photons wavelength, but you introduced an uncertainty in the momentum
Term
 Identify Uncertainty principle equations
Definition
 1)ΔxΔp≥h2)σxσp ≥ ħ/2
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