Recent content by Lisa...

  1. L

    Estimating t Dependency on Proton Separation d

    Please, help me, I keep getting stuck on this and the question is due tomorrow. Now I have the primitive function as the one in the attachment (with x for 'r', l for 'L' and r for 'R'). I don't know how to go further...
  2. L

    Estimating t Dependency on Proton Separation d

    Homework Statement Knowing that the wave function of the hydrogen atom is proportional to e-r/a0, estimate how t depends on the proton proton separation d. I need just to make a drawing of the integrand and make a reasonal approximation using my intuition (no numerical methods allowed to...
  3. L

    Thermodynamics: calculate q, w, E,H,S for a 5 step process

    Thank you so very very much! :) Now I can finish the problem! You're great :D Oh btw and I guess that delta E can be calculated with this total work and the TOTAL q right?
  4. L

    Thermodynamics: calculate q, w, E,H,S for a 5 step process

    On a second thought, I don't think my edit is such a brilliant idea, because then q= n Cp delta T should be 0 too for step II and IV which can't be cause heat is neaded to melt the ice/vaporize the water. I know I need densities of -30,0°C ice (solid), 0°C ice/water (solid/liquid), 100°C...
  5. L

    Thermodynamics: calculate q, w, E,H,S for a 5 step process

    Or perhaps it is necessary to calculate w and E directly for the transition (solid) => (gas) with: w = -p \Delta V = - n R \Delta T and \Delta E = \frac{3}{2} R \Delta T (=q +w) and q= \Delta H = \frac{5}{2} \Delta T
  6. L

    Thermodynamics: calculate q, w, E,H,S for a 5 step process

    I need to calculate q, w, \Delta E, \Delta H and \Delta S for the process of heating a sample of ice weighing 18.02 g (1 mole) from -30.0 °C to 140.0°C at constant pressure of 1 atm. Given are the temperature independent heat capacities (Cp) for solid, liquid and gaseous water: 37.5 J/K/mol...
  7. L

    Electrophilic addition, elimination and stuff like that

    Could you please explain how to resonate the double bond into the ring in part A5 and how BH3 & H2O2 would react, because I can't find it in my literature. To get part A2, isn't a keto-enol tautomerization a possibility? Could you please help me with the other questions, cause I really...
  8. L

    Electrophilic addition, elimination and stuff like that

    Hi! I've made the following assignments and I'll appreciate it if anybody of you can help me with them and correct me if my answer is wrong. Thanks a lot! A) Provide reagents that could be used to effect the transformation of 'Stof A' to each of the following compounds (1-5)...
  9. L

    Challenging QM problem on coupling two 2-level systems with dipole moments

    Hi Patrick! Today in college I've checked it with my professor. He immediately confessed the word force should be replaced by potential as you suggested. So I've done a Taylor expansion on L= E - sqrt{E^2 + U ^2} Using U << E the Taylor series are: L(U)= L(0) + \frac{1}{1!}...
  10. L

    Challenging QM problem on coupling two 2-level systems with dipole moments

    I've checked my notes and the only thing my prof told me about this, is that he mentioned the Lennard Jones potential. It shows that at a short distance the potential is proportional to 1/r12 (molecules are close to one another and repulse each other), though at large distances it goes with...
  11. L

    Challenging QM problem on coupling two 2-level systems with dipole moments

    Oh and as for: The *minus* derivative of: E - sqrt{E^2+ (\frac{1}{4 \pi \epsilon_0 z^3} \mu_1 \mu_2)^2} would be \frac{-3 \mu_1^2 \mu_2^2}{8 \pi^2 \epsilon_0^2 z^7} \frac{1}{2 sqrt{E^2 + \frac{\mu_1^2 \mu_2^2}{16 \pi^2 \epsilon_0^2 z^6}}} assuming E is independent of z (is...
  12. L

    Challenging QM problem on coupling two 2-level systems with dipole moments

    So I have A= \left(\begin{array}{cc}0&U\\U&2E\end{array}\right) B= \left(\begin{array}{cc}E&U\\U&E\end{array}\right) (I'll use L for lambda) Eigenvalues of A are found by using: det(A-LI)=0 \left(\begin{array}{cc}-L&U\\U&2E-L\end{array}\right) = 0 L2 - 2EL -U2 =0...
  13. L

    Challenging QM problem on coupling two 2-level systems with dipole moments

    Hey! My teacher gave me a very challenging problem on QM. I've only had one introductiary course, but he said he wanted me to figure this problem out by using whatever resources, so now I turn to you guys ;-). The problem is the following: London attraction forces can be thought of as...
  14. L

    Series RLC filter (trap filter)

    This is what I've done. Please tell me if I've done it okay, cause I need to deliver it in 2 hours...: V= IR, so Vin= IZ = I \sqrt{R^2 + (wl - \frac{1}{wc})^2} Vin= IR \sqrt{1 + (\frac{wl - 1/wc}{R})^2} so \frac{(wl - 1/wc)}{R} = + or - 1 to give sqrt(2) \frac{wl}{R} -...
Back
Top