Please believe me when I saw that I have literally tried solving these problems for hours. I have a test coming up and really need to move on and focus on that. I missed the 2 classes regarding these topics and can't seem to figure these four questions out! Any steps/answers to help solving these problems would be amazing!
1. An electron in an excited state of a hydrogen atom emits two photons in succession, the first at 1875 nm and the second at 102.5 nm, to return to the ground state (n=1). For a given transition, the wavelength of the emitted photon corresponds to the difference in energy between the two energy levels. What were the principal quantum numbers of the initial and intermediate excited states involved?
E=hc/¥
=2.18x10^-18 J (1/nf^2 - 1/ni^2)
=(6.63x20^-34)x(3.00x10^8m/s)/(102.5x10^-9m) =1.94x10^-18
1.94x10^-18=2.18x10^-18J (1/1-1/ni^2)
1.94x10^-18/2.18x10^-18 =.8899
.8899=1-1/ni^2
I don't know if i'm going about this right.but i'm pretty lost at this point.
2. An electron in an excited state of hydrogen undergoes a transition to the n = 3 level. In the process, a photon of energy 1.82×10-19 J is emitted. What was the value of the principal quantum number for the higher energy level?
I don't even know where to start with this.
3. Calculate the frequency (in Hz) of a photon emitted during a transition corresponding to the second line in the Paschen series (nf = 3) of the hydrogen emission spectrum.
E=-Rhc (1/nf^2)-(1/ni^2)
E=-(1.0974x10^7)(6.63x10^34)(2.998x10^^8)(1/3^2)-(1/4^2)
=(2.18x10^18)(.11)-(0.0625)=1.035x10^-19J
E=6.86x10^23 (wrong)
4. Calculate the energy of one mole of photons (in kJ/mol) that has a wavelength of 2.15×103 nm.
E=hc/¥
(6.26x10^-34J/s)(2.998x10^8 m/s)/(2.15x10^9m/s)(1m/1x10^9nm)
=1.876x10^-25/2.15x10^-6
=8.725x10^-20J -which is wrong
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Topic: Questions about Quantum numbers and photons. Help (Read 5545 times)