Packet 7: Bonus 12
These molecules have good foaming ability when their head group is anionic. For 10 points each:
[10m] Name these molecules, the main active ingredient of detergents. These amphiphilic molecules aggregate into spherical micelles that remove grease and soiling particles.
ANSWER: surfactants [or surface-active agents; accept anionic surfactants]
[10h] Detergent surfactants reduce the surface tension of water by undergoing this process at the liquid-air interface. Irving Langmuir developed an isotherm model of this process that assumes the formation of a monolayer.
ANSWER: adsorption [accept word forms like adsorbing; accept Langmuir adsorption isotherm or Langmuir adsorption model; prompt on binding; reject “absorption”]
[10e] Many detergents also contain enzymes, biological examples of these substances. These substances increase the rate of chemical reactions but are not consumed in the process.
ANSWER: catalysts
<McGill A, Chemistry> | Packet G
| Editions | Heard | PPB | Easy % | Medium % | Hard % |
|---|---|---|---|---|---|
| 2 | 110 | 14.09 | 98% | 33% | 10% |
Conversion
| Team | Opponent | Part 1 | Part 2 | Part 3 | Total | Parts |
|---|---|---|---|---|---|---|
| Durham C | Durham B | 0 | 0 | 10 | 10 | E |
| Durham D | Durham A | 0 | 0 | 10 | 10 | E |
| Edinburgh D | Edinburgh B | 0 | 0 | 10 | 10 | E |
| Sheffield B | Edinburgh A | 0 | 10 | 10 | 20 | HE |
| York | Sheffield A | 0 | 0 | 10 | 10 | E |
Summary
| Tournament | Edition | Exact Match? | Heard | PPB | Easy % | Medium % | Hard % |
|---|---|---|---|---|---|---|---|
| UK (North) | UK | Y | 5 | 12.00 | 100% | 0% | 20% |
| UK (South) | UK | Y | 8 | 11.25 | 100% | 0% | 13% |
| Northern California | US | Y | 4 | 25.00 | 100% | 100% | 50% |
| Southern California | US | Y | 7 | 14.29 | 100% | 29% | 14% |
| Eastern Canada (1) | US | Y | 4 | 12.50 | 100% | 25% | 0% |
| Eastern Canada (2) | US | Y | 9 | 11.11 | 89% | 22% | 0% |
| Florida | US | Y | 4 | 15.00 | 100% | 50% | 0% |
| Great Lakes | US | Y | 11 | 16.36 | 100% | 55% | 9% |
| Lower Mid-Atlantic | US | Y | 9 | 14.44 | 100% | 33% | 11% |
| Upper Mid-Atlantic | US | Y | 9 | 13.33 | 100% | 22% | 11% |
| Midwest | US | Y | 9 | 14.44 | 89% | 33% | 22% |
| North | US | Y | 4 | 17.50 | 100% | 50% | 25% |
| Pacific | US | Y | 8 | 15.00 | 100% | 50% | 0% |
| South Central | US | Y | 6 | 15.00 | 100% | 50% | 0% |
| Southeast | US | Y | 12 | 10.83 | 100% | 8% | 0% |
| Upstate NY | US | Y | 1 | 20.00 | 100% | 100% | 0% |