Packet 9: Bonus 6
Heating barium with arsenic leads to the formation of one of these compounds. For 10 points each:
[10h] Name these intermetallic compounds generally formed by reacting Group IA (“one-A”) or IIA (“two-A”) metals with a metalloid from a later group in the periodic table.
ANSWER: Zintl phases [or Zintl compounds; accept Zintl anions]
[10e] The first Zintl phases were formed by dissolving lead and sodium in a liquid of this compound. This compound is synthesized by hydrogenating nitrogen in the Haber-Bosch process.
ANSWER: ammonia [or NH3; reject “ammonium” or “NH4+”]
[10m] Ethylene·di·amine, crown ethers, and these ligands can chelate to cations and form Zintl phases in ammonia. These polycyclic ligands, an example of which is denoted [2.2.2] (“2, 2, 2”), are considered 3-D analogs of crown ethers.
ANSWER: cryptands [accept cryptates; accept cryptand solutions; accept [2.2.2]Cryptand or crypt-222]
<KN, Chemistry> | NAFTA-Packet-9
| Heard | PPB | E % | M % | H % |
|---|---|---|---|---|
| 35 | 12.00 | 100% | 20% | 0% |
Conversion
| Team | Opponent | Part 1 | Part 2 | Part 3 | Total | Parts |
|---|---|---|---|---|---|---|
| Berkeley A | Constans Constantius and Constantine Jr. | 0 | 10 | 10 | 20 | EM |
| Not Old! (Old) | Team 7 | 0 | 10 | 0 | 10 | E |
| Stanford A | Stanford B | 0 | 10 | 0 | 10 | E |
| Team 8 | Berkeley B | 0 | 10 | 0 | 10 | E |
Summary
| Tournament | Edition | Match | Heard | PPB | E % | M % | H % |
|---|---|---|---|---|---|---|---|
| 2026 NAFTA at Stanford | 01/17/2026 | ✓ | 4 | 12.50 | 100% | 25% | 0% |
| 2026 NAFTA at UBC | 01/17/2026 | ✓ | 2 | 10.00 | 100% | 0% | 0% |
| 2025 NAFTA Online | 02/14/2026 | ✕ | 4 | 10.00 | 100% | 0% | 0% |
| 2026 NAFTA at Vanderbilt | 02/14/2026 | ✕ | 3 | 20.00 | 100% | 67% | 33% |
| 2025 NAFTA at Toronto | 09/13/2025 | ✓ | 5 | 10.00 | 100% | 0% | 0% |
| 2025 NAFTA at Maryland | 09/27/2025 | ✓ | 5 | 12.00 | 100% | 20% | 0% |
| 2025 NAFTA at Harvard | 10/04/2025 | ✓ | 3 | 13.33 | 100% | 33% | 0% |
| 2025 NAFTA at Oxford | 10/11/2025 | ✓ | 3 | 10.00 | 100% | 0% | 0% |
| 2025 NAFTA at Chicago | 11/08/2025 | ✓ | 6 | 13.33 | 100% | 33% | 0% |
| 2025 NAFTA at Columbia | 11/08/2025 | ✓ | 5 | 14.00 | 100% | 40% | 0% |
| 2025 NAFTA at Richmond | 12/20/2025 | ✓ | 2 | 10.00 | 100% | 0% | 0% |