Packet 7: Bonus 22
Since quantum dots tend to be hydrophobic and cytotoxic, they are often encapsulated into a network of these materials to be used in biological systems. For 10 points each:
[10m] Name these materials whose “self-healing” type may be used as scaffolds in tissue engineering. These materials are made of cross-linked polymers mixed with water.
ANSWER: hydrogels [prompt on gels]
[10e] During encapsulation of a quantum dot, a shell composed of this metal’s sulfide helps prevent clumping of cadmium-selenium particles. This metal alloys with copper to form brass.
ANSWER: zinc [or Zn]
[10h] When using modified polyethylene glycol as the surfactant, encapsulation occurs spontaneously at the Krafft temperature, where solubility is nearly equal to this other parameter. Surface tension remains relatively constant after colloidal mixtures reach this value.
ANSWER: critical micelle concentration [or CMC; prompt on concentration]
<MS, Chemistry> | NAFTA-Packet-7
| Heard | PPB | E % | M % | H % |
|---|---|---|---|---|
| 9 | 8.89 | 44% | 33% | 11% |
Conversion
| Team | Opponent | Part 1 | Part 2 | Part 3 | Total | Parts |
|---|---|---|---|---|---|---|
| It's something unpredictable/that in the end is right/please refrain from e-mailing my wife | Polish Orthographers Posting Their Łs | 0 | 0 | 0 | 0 |
Summary
| Tournament | Edition | Match | Heard | PPB | E % | M % | H % |
|---|---|---|---|---|---|---|---|
| 2026 NAFTA at Stanford | 01/17/2026 | ✓ | 3 | 13.33 | 67% | 67% | 0% |
| 2025 NAFTA Online | 02/14/2026 | ✓ | 2 | 15.00 | 50% | 50% | 50% |
| 2025 NAFTA at Toronto | 09/13/2025 | ✓ | 1 | 0.00 | 0% | 0% | 0% |
| 2025 NAFTA at Oxford | 10/11/2025 | ✓ | 1 | 10.00 | 100% | 0% | 0% |
| 2025 NAFTA at Chicago | 11/08/2025 | ✓ | 1 | 0.00 | 0% | 0% | 0% |
| 2025 NAFTA at Richmond | 12/20/2025 | ✓ | 1 | 0.00 | 0% | 0% | 0% |