Question 19M.2.hl.TZ2.2d
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.2.hl.TZ2.2d |
| Level | hl | Paper | 2 | Time zone | TZ2 |
| Command term | Sketch | Question number | d | Adapted from | N/A |
The thermal decomposition of dinitrogen monoxide occurs according to the equation:
2N2O (g) → 2N2 (g) + O2 (g)
The reaction can be followed by measuring the change in total pressure, at constant temperature, with time.
The x-axis and y-axis are shown with arbitrary units.
The experiment is repeated using the same amount of dinitrogen monoxide in the same apparatus, but at a lower temperature.
Sketch, on the axes in question 2, the graph that you would expect.
[2]
smaller initial gradient [✔]
initial pressure is lower AND final pressure of gas lower «by similar factor» [✔]
Many students drew a lower initial gradient, but most did not reflect the effect of lower temperature on pressure at constant volume and started and finished the curve at the same pressure as the original one.
