The origin of crude oil
3 marks · EasyThe table shows four hydrocarbons found in crude oil. Use the data to answer the questions.
| Hydrocarbon | Number of carbon atoms | Boiling point (°C) |
|---|---|---|
| A | 5 | 36 |
| B | 10 | 174 |
| C | 15 | 269 |
| D | 20 | 343 |
Which hydrocarbon in the table has the highest boiling point?
Describe the trend shown between the number of carbon atoms and boiling point.
Predict the boiling point for a hydrocarbon with 12 carbon atoms, using the trend shown.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) D
(b) Boiling point increases as the number of carbon atoms increases
(c) around 200 to 200.5 °C
Common mistakes: Selecting highest number of carbon atoms but not the correct hydrocarbon label
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Identifies hydrocarbon D as having the highest boiling point
B1 (b) · 1 mark · States boiling point increases with number of carbon atoms
A1 (c) · 1 mark · Predicts a boiling point of about 200 °C (±5 °C) for 12 carbon atoms based on the trend
Worked solution
a) D has the highest boiling point.
b) Boiling point increases as the number of carbon atoms increases.
c) Predicted value: about 200 °C