Question 19M.2.SL.TZ2.2dii
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.2.SL.TZ2.2dii |
| Level | SL | Paper | 2 | Time zone | TZ2 |
| Command term | Explain | Question number | dii | Adapted from | N/A |
Explain, using your answer to (d)(i) and with reference to the kinetic model, why this sample of helium can be assumed to be an ideal gas.
[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 (d)(i) shows that volume of helium atoms is negligible compared to/much smaller than volume of helium gas/container «hence assumption is justified» ✔
In general this was poorly answered at SL. Many other non-related gas properties given such as no / negligible intermolecular forces, low pressure, high temperature. Some candidates interpreted the ratio as meaning it is a low density gas. 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.
