DP Chemistry (last assessment 2024)
Question 19N.2.hl.TZ0.3b(i)
| Date | November 2019 | Marks available | [Maximum mark: 3] | Reference code | 19N.2.hl.TZ0.3b(i) |
| Level | hl | Paper | 2 | Time zone | TZ0 |
| Command term | Determine | Question number | b(i) | Adapted from | N/A |
b(i).
[Maximum mark: 3]
19N.2.hl.TZ0.3b(i)
Propene is an important starting material for many products. The following shows some compounds which can be made from propene, C3H6.
Propene (C3H6) → C3H7Cl → C3H8O → C3H6O
An experiment was carried out to determine the order of reaction between one of the isomers of C3H7Cl and aqueous sodium hydroxide. The following results were obtained.
(b(i))
Determine the rate expression from the results, explaining your method.
[3]
Markscheme
Rate = k [C3H7Cl] [OH−] ✔
«[OH−] held constant and» [C3H7Cl] triples AND rate triples «so first order wrt C3H7Cl» ✔
[C3H7Cl] doubles AND [OH−] doubles AND rate quadruples «so first order wrt OH−» ✔
