DP Chemistry (last assessment 2024)
Question 18M.3.sl.TZ2.5a
| Date | May 2018 | Marks available | [Maximum mark: 2] | Reference code | 18M.3.sl.TZ2.5a |
| Level | sl | Paper | 3 | Time zone | TZ2 |
| Command term | State | Question number | a | Adapted from | N/A |
a.
[Maximum mark: 2]
18M.3.sl.TZ2.5a
Chemical vapour deposition (CVD) produces multi-walled carbon nanotubes (MWCNT) of a more appropriate size for use in liquid crystals than production by arc discharge.
(a)
State the source of carbon for MWCNT produced by arc discharge and by CVD.
[2]
Markscheme
Arc discharge:
graphite electrode
OR
hydrocarbon solvent
CVD:
gaseous hydrocarbons
Accept “carbon electrode”.
Accept specific examples of suitable hydrocarbon solvents (eg, methyl benzene/toluene OR cyclohexane).
Accept specific examples of suitable gaseous hydrocarbons (eg, methane, ethane, ethyne/acetylene) OR carbon monoxide OR carbon dioxide.
[2 marks]