Which one of the following statements about mass spectrometry is always correct?
A - VCE - SSCE Chemistry - Question 29 - 2023 - Paper 1
Question 29
Which one of the following statements about mass spectrometry is always correct?
A. The relative molecular mass of a molecule is determined from the base peak.
B. ... show full transcript
Worked Solution & Example Answer:Which one of the following statements about mass spectrometry is always correct?
A - VCE - SSCE Chemistry - Question 29 - 2023 - Paper 1
Step 1
A. The relative molecular mass of a molecule is determined from the base peak.
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Answer
This statement is incorrect. The relative molecular mass is determined from the molecular ion peak, which is not necessarily the base peak.
Step 2
B. The peaks in a mass spectrum are caused by the presence of different isotopes.
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Answer
While peaks can be caused by isotopes, they can also arise from fragmentation. Thus, this statement is not always correct.
Step 3
C. The base peak is formed when an uncharged species is removed from the molecule.
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Answer
This statement is incorrect. The base peak is the most intense peak in the spectrum, representing the most abundant ion, not necessarily formed from the removal of any species.
Step 4
D. The height of each peak in the mass spectrum is measured relative to the height of the base peak.
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Answer
This statement is correct. In mass spectrometry, the heights of the other peaks are expressed relative to the height of the base peak, which is assigned a value of 100%.
