A student notes question tests whether you can use the notes to do the writer’s stated job. Read the goal first and work out what the goal needs: an explanation needs reasons, not only facts about the topic. For a goal about combining two methods, ask what each can show and what it cannot. Then check every claim against the notes, including how certain the results are. A sentence can address the goal and still claim more than the notes support.
Hints
- Hint 1
Read the full goal, including the words about relying on either technique alone. What does the student want the reader to understand about using both?
- Hint 2
Look in the Raman and XRF notes for what each technique could and could not reveal.
- Hint 3
Compare the measured results with the reference analysis. How much can that comparison tell you about the colorant’s identity?
Step-by-step
Explain the combined value, then check the claims
Step 1Work out what the goal needs
Read explain why combining Raman spectroscopy and XRF alongside rather than relying on either technique alone. What should that explanation include? The answer needs to give a reason for using both techniques to identify the colorant: what each adds that the other cannot give.
- Step 2
Pair each result with its limit
What did each technique reveal, and what couldn't it show? Raman found an indigo molecular framework, but fluorescence hid the bands that could show whether bromine was attached. XRF detected bromine in the thread, but it cannot show how those elements are arranged within molecules. So Raman gives the framework, and XRF adds bromine’s presence, without showing that the bromine is attached to that framework.
- Step 3
Test the claims against the notes
Which features belong to the named colorant? The reference note says 6,6′-dibromoindigo contains both an indigo framework and attached bromine atoms, so each measurement alone is missing part of that picture. Either result independently identified the compound ignores that missing part. The claim established that the atoms occupied the 6,6′ positions gives XRF a power it doesn't have, because XRF can't place bromine within a molecule.
- Step 4
Distinguish support from proof
How far can the sentence go? The goal says supported the researchers’ identification, so we need evidence for the colorant, not proof that rules out every other colorant. Conclusively demonstrated and only make that extra claim even though bromine’s attachment wasn't shown. The sentence saying the results support identifying 6,6′-dibromoindigo explains their combined value without claiming proof. Choice A.