| Date | May 2016 | Marks available | 1 | Reference code | 16M.3.sl.TZ0.4 |
| Level | SL | Paper | 3 | Time zone | TZ0 |
| Command term | Identify | Question number | 4 | Adapted from | N/A |
Question
Nanocatalysts have large surface areas per unit mass.
Identify one concern of using nanoscale catalysts.
Explain how zeolites act as selective catalysts.
Carbon nanotubes, which can be produced by the HIPCO process, show great potential as nanocatalysts. Identify the catalyst and conditions used in the HIPCO process.
Catalyst:
Conditions:
Markscheme
possible toxicity «of small airborne particles»
OR
unknown health effects
OR
small particle size «and large surface area» may increase reaction rate to dangerous levels
OR
immune system/allergy concerns
OR
uncertain impact on environment
Accept specific health effect (eg. may cause cancer/effect on respiratory system, etc).
pores/cavities/channels/holes/cage-like structures «in zeolites» have specific shape/size
only reactants «with appropriate size/geometry» fit inside/go through/are activated/can react
Catalyst:
iron/Fe
OR
iron«0» «penta» carbonyl/Fe (CO)5
Conditions:
high temperature/any value or range within the range 900–1600 °C
AND
high pressure/any value or range within the range 10–100 atm
Accept “cobalt-molybdenum/Co-Mo/CoMo”.
Accept high pressures expressed in kPa/Pa.
