Question
Answer the following about what makes a molecule a good greenhouse gas, for 10 points each.
[10e] A good greenhouse gas must be able to absorb and re-emit thermal radiation from the Earth, which is mostly in this region of the EM spectrum that is slightly less energetic than visible light.
ANSWER: infrared light [or IR light; accept near IR light]
[10m] Diatomic molecules like oxygen and nitrogen aren't greenhouse gasses because IR-active vibrational modes must be accompanied by a change in this quantity, which is zero for O2 and N2.
ANSWER: dipole moment [prompt on electric dipole moment; prompt on polarity]
[10h] A 2024 paper by Wordsworth et al. suggests that CO2 is so effective as a greenhouse gas because its absorption range is significantly broadened by a coincidental Fermi resonance between a bending mode and its first of these modes. In this vibrational mode, bonds lengthen and contract together.
ANSWER: symmetric stretch [prompt on stretching modes]
<VD, Chemistry>
Summary
| 2024 ARCADIA at UC Berkeley | 2024-12-06 | Y | 2 | 15.00 | 100% | 50% | 0% |
| 2024 ARCADIA at Waterloo | 2024-11-09 | Y | 1 | 10.00 | 100% | 0% | 0% |
| 2024 ARCADIA at GT | 2024-12-06 | Y | 1 | 10.00 | 100% | 0% | 0% |
| 2024 ARCADIA at Illinois | 2024-11-09 | Y | 1 | 10.00 | 100% | 0% | 0% |
| 2024 ARCADIA at Warwick | 2024-12-06 | Y | 2 | 10.00 | 100% | 0% | 0% |
Data
| Cambridge A | Imperial B | 10 | 0 | 0 | 10 |
| LSE B | Warwick A | 10 | 0 | 0 | 10 |