| Date | May 2011 | Marks available | 1 | Reference code | 11M.1.SL.TZ2.11 |
| Level | Standard level | Paper | Paper 1 | Time zone | Time zone 2 |
| Command term | Question number | 11 | Adapted from | N/A |
Question
The volume of an ideal gas in a container is increased at constant temperature. Which of the following statements is/are correct about the molecules of the gas?
I. Their average speed remains constant.
II. The frequency of collisions of molecules with unit area of the container wall decreases.
III. The force between them decreases.
A. I only
B. I and II only
C. I and III only
D. II and III only
Markscheme
B
Examiners report
As many teachers noted there was no correct answer to this question as the word ‘average’ was omitted from the stem leading a significant number of candidates to opt for D. This question was, therefore, discounted from both SL and HL.
