DP Chemistry (last assessment 2024)

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Question 19M.3.sl.TZ1.3b(i)

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Date May 2019 Marks available [Maximum mark: 1] Reference code 19M.3.sl.TZ1.3b(i)
Level sl Paper 3 Time zone TZ1
Command term Suggest Question number b(i) Adapted from N/A
b(i).
[Maximum mark: 1]
19M.3.sl.TZ1.3b(i)

Lithium has many uses.

The emission spectra obtained by ICP-OES for a mixture containing the isotope 6Li (Li-6) and naturally occurring lithium (Li (N)) is shown.

(b(i))

Suggest why ICP-OES does not give good quantitative results for distinguishing 6Li from naturally occurring lithium.

[1]

Markscheme

emission spectra of both «6Li and natural Li» give same colour/produce same «range of» wavelengths
OR
they have same electron transitions/same nuclear charge  [✔]

 

Note: Accept “the spectra are almost identical”.

Examiners report

Surprisingly few candidates referred to the fact that the two spectra shown are almost identical.

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