DP Chemistry (first assessment 2025)
Question 19M.2.SL.TZ1.b
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.2.SL.TZ1.b |
| Level | SL | Paper | 2 | Time zone | TZ1 |
| Command term | Calculate | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 2]
19M.2.SL.TZ1.b
Mass spectrometry analysis of a sample of iron gave the following results:
Calculate the relative atomic mass, Ar, of this sample of iron to two decimal places.
[2]
Markscheme
«Ar =» 54 × 0.0584 + 56 × 0.9168 + 57 × 0.0217 + 58 × 0.0031
OR
«Ar =» 55.9111 [✔]
«Ar =» 55.91 [✔]
Notes:
Award [2] for correct final answer.
Do not accept data booklet value (55.85).
Examiners report
Calculation of RAM was generally correctly calculated, but some candidates did not give their answer to two decimal places while they should use the provided periodic table.
Syllabus sections
Structure 1. Models of the particulate nature of matter » Structure 1.2—The nuclear atom » Structure 1.2.3—Mass spectra. Mass spectra are used to determine the relative atomic masses of elements from their isotopic composition. Interpret mass spectra in terms of identity and relative abundance of isotopes.