Question 19M.2.SL.TZ2.cii
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.2.SL.TZ2.cii |
| Level | SL | Paper | 2 | Time zone | TZ2 |
| Command term | Discuss | Question number | cii | Adapted from | N/A |
Discuss, by reference to the kinetic model of an ideal gas and the answer to (c)(i), whether the assumption that helium behaves as an ideal gas is justified.
[2]
«For an ideal gas» the size of the particles is small compared to the distance between them/size of the container/gas
OR
«For an ideal gas» the volume of the particles is negligible/the volume of the particles is small compared to the volume of the container/gas
OR
«For an ideal gas» particles are assumed to be point objects ✔
calculation/ratio/result in (c)(i) shows that volume of helium atoms is negligible compared to/much smaller than volume of helium gas/container «hence assumption is justified» ✔
At HL candidates seemed more able to focus on the key part feature of the question, which was the nature of the volumes involved. Examiners were looking for an assumption of the kinetic theory related to the volume of the atoms/gas and then a link to the ratio calculated in ci). The command terms were slightly different at SL and HL, giving slightly more guidance at SL.
