{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Chapter 3 part 2a - Review So Far The shape of a molecule...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Chemistry in Context Chapter 3 Part 2 The Chemistry of Global Warming Review So Far The shape of a molecule is determined from Lewis diagrams and RHED. Whether a molecule is IR active depends, in part, on its shape. IR active molecules absorb IR waves of a higher energy then re-emit waves of a lower energy. Review So Far Chemistry Topics: – Lewis dot diagrams and Lewis line diagrams – Octet rule and exceptions to the octet Less than octet Expanded octet • Ions – Calculations involving E, v, λ , c, h. Note Electronegativity and polarity will be covered on a later date.
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
2 Today’s Focus Areas Infrared radiation, IR spectra, IR active Average molecular mass • Moles Recall In order for a vibrational mode to be infrared active, it must change the molecule’s dipole moment. Question Which of the following diatomic molecules will be infrared active? 1) O 2 2) N 2 3) Cl 2 4) H 2 5) All of them 6) None of the other answers are correct Question You know these are IR active: – H 2 O – CO 2 Which of the following molecules would you expect to have at least one infrared active vibrational mode? – N 2 – Ar – SO 2 – O 3
Image of page 2
3 Common Infrared Stretching and Bending Infrared Spectrum How an IR works: – Radiation source – Beam passes through sample – Sample absorbs a portion of the beam, depending on the sample’s molecules and vibrational modes – Leftover beam goes to detector – Graph is plotted (insert IR spectrum) From textbook Question Why would scientists choose to use inverse wavelength as the X-axis, instead of wavelength?
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern