DP Chemistry (first assessment 2025)
Question 19M.2.SL.TZ2.c(i)
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.2.SL.TZ2.c(i) |
| Level | SL | Paper | 2 | Time zone | TZ2 |
| Command term | Suggest | Question number | c(i) | Adapted from | N/A |
c(i).
[Maximum mark: 2]
19M.2.SL.TZ2.c(i)
Suggest two reasons why oil decomposes faster at the surface of the ocean than at greater depth.
[2]
Markscheme
Any two of:
surface water is warmer «so faster reaction rate»/more light/energy from the sun [✔]
more oxygen «for aerobic bacteria/oxidation of oil» [✔]
greater surface area [✔]
Examiners report
While many candidates did receive two marks for this question some candidates only suggested one reason or repeated the same reason (for example - heat and energy from the sun) even though the question clearly asked for two reasons.
Syllabus sections
Reactivity 2. How much, how fast and how far? » Reactivity 2.2—How fast? The rate of chemical change » Reactivity 2.2.3—Factors that influence the rate of a reaction include pressure, concentration, surface area, temperature and the presence of a catalyst. Predict and explain the effects of changing conditions on the rate of a reaction.