DP Chemistry (last assessment 2024)
Question 21M.2.hl.TZ1.b
| Date | May 2021 | Marks available | [Maximum mark: 2] | Reference code | 21M.2.hl.TZ1.b |
| Level | hl | Paper | 2 | Time zone | TZ1 |
| Command term | Explain | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 2]
21M.2.hl.TZ1.b
Oxygen exists as two allotropes, diatomic oxygen, O2, and ozone, O3.
Explain why there are frequencies of UV light that will dissociate O3 but not O2.
[2]
Markscheme
bond in O3 is weaker
OR
O3 bond order 1.5/< 2 ✔
Do not accept bond in O3 is longer for M1.
lower frequency/longer wavelength «UV light» has enough energy to break the O–O bond in O3 «but not that in O2» ✔
Accept “lower frequency/longer wavelength «UV light» has lower energy”.
