1 / 22

Thermal & Kinetic Lecture 10 Revision I: Problems and Previous Exam. Questions

Thermal & Kinetic Lecture 10 Revision I: Problems and Previous Exam. Questions. I would prefer to have the slides available from the website before the lecture. Yes No Don’t care. Equipartition and Specific Heats. Thermal & Kinetic paper, ’06/’07: Q1. For this question,.

clayton-ayala
Télécharger la présentation

Thermal & Kinetic Lecture 10 Revision I: Problems and Previous Exam. Questions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Thermal & Kinetic Lecture 10 Revision I: Problems and Previous Exam. Questions

  2. I would prefer to have the slides available from the website before the lecture. • Yes • No • Don’t care

  3. Equipartition and Specific Heats

  4. Thermal & Kinetic paper, ’06/’07: Q1

  5. For this question, • I don’t know where to begin • I could have a go but I’m not sure • I am confident that I can do it

  6. The value of CV expected if all degrees of freedom contribute is: • 24.93 JK-1 • 12.46 JK-1 • 29.08 JK-1 • None of these

  7. Thermal & Kinetic paper, ’02/’03: Paper 2, Q1

  8. Vibrational effects… • Won’t contribute • Will contribute • Don’t know

  9. (b) (i)kT at room temperature ~ 0.025 eV. Spacing of vibrational levels ~ 1 order of magnitude greater than this – vibrational contribution will be negligible.

  10. At what temperature will the population of the first excited vibrational level be a factor of ten greater than the number of molecules in the second vibrational level? • 512 K • 1361 K • 77 K • 2112 K

  11. (b) (ii) ln (10)=0.27 x 1.6 x 10-19/(1.38 x 10-23 x T) [1]  T = 1361 K [1] (b)(iii)Consider independent degrees of freedom of diatomic molecule: 3 translation, 2 vibration, 2 rotation [1]. Each degree of freedom contributes ½ kT in energy, hence Cv = 7k/ 2 (7R/2 for 1 mole) [1] Only have 3 degrees of freedom for monatomic gas, so Cv = 3k/2 (3R/2 for 1 mole) [1]

  12. Thermal & Kinetic paper, ’05/’06: Q3

  13. For this question, • I don’t know where to begin • I could have a go but I’m not sure • I am confident that I can do it

  14. Specific heats and equipartition of energy If the spacing of the rotational energy levels for a certain diatomic molecule is 0.05 eV, would you expect that rotational effects will make a strong contribution to the specific heat of the molecule at a temperature of 4K? What is the heat capacity of the molecule at 4K assuming that both vibrational and rotational motion are ‘frozen out’ at this temperature?

  15. Thermal & Kinetic paper, ’03/’04: Section B Q8 NB You should attempt the remainder of Q8 from the 2004 Thermal & Kinetic paper.

  16. Boltzmann distribution

  17. Thermal & Kinetic paper, ’06/’07: Paper 2, Q1

  18. The dimensions of k are: • MLT-2q • ML2T-1q2 • ML2T-2q-1 • Don’t know

  19. Velocity and speed (Maxwell-Boltzmann) distributions

  20. Thermal & Kinetic paper, ’04/’05: Section B Q7 Formulae given

  21. For this question, • I don’t know where to begin • I could have a go but I’m not sure • I am confident that I can do it

More Related