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At a temperature of 0 K, the total energ...

At a temperature of `0 K`, the total energy of a gaseous diatomic molecule AB is approximately given by:
`E=E_(o)+E_(vib)`
where `E_(o)` is the electronic energy of the ground state, and `E_(vib)` is the vibrational energy.
Allowed values of the vibrational energies are given by the expression:
`E_(vid)=(v-1/2)epsilon " " v=0, 1, 2, ....... " " epsilon=h/(2pi)sqrt(k/mu) " " mu(AB)=(m_(A)m_(B))/(m_(A)+m_(B))`
where h is the planck's constant, is the vibration quantum number, k is the force constant, and is the reduced mass of the molecule. At `0K`, it may be safely assumed that is zero, and `E_(o)` and `k` are independent of isotopic substitution in the molecule.
Deuterium, D, is an isotope of hydrogen atom with mass number `2`. For the `H_(2)` molecule, k is `575.11 N m^(-1)`, and the isotopic molar masses of H and D are `1.0078` and `2.0141 g mol^(-1)`, respectively.
At a temperature of `0K : epsilon_(H_(2))=1.1546 epsilon_(HD)` and `epsilon_(D_(2))=0.8167 epsilon_(HD)`
A molecule `H_(2)` in the ground state dissociates into its atoms after absorbing a photon of wavelength `77.0 nm`. `ul("Determine")` all possibilities for the electronic states of hydrogen atoms produced. For each case calculate the total kinetic energy, KE, in eV of the disociated hydrogen atoms.

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To solve the problem, we need to determine the electronic states of the hydrogen atoms produced from the dissociation of the H₂ molecule and calculate the total kinetic energy (KE) of the dissociated hydrogen atoms. Here’s a step-by-step breakdown of the solution: ### Step 1: Understand the Dissociation Process When the H₂ molecule absorbs a photon of wavelength 77.0 nm, it dissociates into two hydrogen atoms. The energy of the photon can be calculated using the equation: \[ E = \frac{hc}{\lambda} \] where: - \( h \) is Planck's constant (\( 6.626 \times 10^{-34} \, \text{J s} \)), - \( c \) is the speed of light (\( 3.00 \times 10^8 \, \text{m/s} \)), - \( \lambda \) is the wavelength of the photon (77.0 nm = \( 77.0 \times 10^{-9} \, \text{m} \)). ### Step 2: Calculate the Energy of the Photon Substituting the values into the equation: \[ E = \frac{(6.626 \times 10^{-34} \, \text{J s})(3.00 \times 10^8 \, \text{m/s})}{77.0 \times 10^{-9} \, \text{m}} \] Calculating this gives: \[ E \approx 2.58 \times 10^{-18} \, \text{J} \] ### Step 3: Convert Energy to Electron Volts To convert the energy from joules to electron volts (1 eV = \( 1.602 \times 10^{-19} \, \text{J} \)): \[ E \approx \frac{2.58 \times 10^{-18}}{1.602 \times 10^{-19}} \approx 16.1 \, \text{eV} \] ### Step 4: Determine the Electronic States of Hydrogen Atoms The dissociation of H₂ produces two hydrogen atoms, which can be in different electronic states. The ground state of hydrogen has an energy of -13.6 eV. The possible electronic states for the hydrogen atoms after dissociation can be: 1. Both hydrogen atoms in the ground state (E = -27.2 eV). 2. One hydrogen atom in the ground state and the other in the first excited state (E = -13.6 eV for one and E = -3.4 eV for the other, total E = -17.0 eV). 3. Both hydrogen atoms in the first excited state (E = -3.4 eV each, total E = -6.8 eV). ### Step 5: Calculate Total Kinetic Energy (KE) The total kinetic energy (KE) of the dissociated hydrogen atoms can be calculated by considering the energy of the photon absorbed and the total energy of the hydrogen atoms in the electronic states: 1. **Both in Ground State:** \[ KE = E_{photon} - E_{total} = 16.1 \, \text{eV} - (-27.2 \, \text{eV}) = 43.3 \, \text{eV} \] 2. **One in Ground State, One in First Excited State:** \[ KE = 16.1 \, \text{eV} - (-17.0 \, \text{eV}) = 33.1 \, \text{eV} \] 3. **Both in First Excited State:** \[ KE = 16.1 \, \text{eV} - (-6.8 \, \text{eV}) = 22.9 \, \text{eV} \] ### Summary of Results - **Both in Ground State:** KE = 43.3 eV - **One in Ground State, One in First Excited State:** KE = 33.1 eV - **Both in First Excited State:** KE = 22.9 eV
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