Molecule V contains only carbon atoms, hydrogen atoms and one oxygen atom - VCE - SSCE Chemistry - Question 7 - 2023 - Paper 1
Question 7
Molecule V contains only carbon atoms, hydrogen atoms and one oxygen atom.
The mass spectrum of molecule V is shown below.
(a) i. State the molecular formula of mol... show full transcript
Worked Solution & Example Answer:Molecule V contains only carbon atoms, hydrogen atoms and one oxygen atom - VCE - SSCE Chemistry - Question 7 - 2023 - Paper 1
Step 1
State the molecular formula of molecule V. Justify your answer by using the information in the mass spectrum.
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Answer
The molecular formula of molecule V is C₅H₈O. This is derived from analyzing the mass spectrum, where the most significant peak is located at m/z = 86, indicating the molar mass of the compound is 86 g/mol. The presence of carbon, hydrogen, and one oxygen atom suggests that the molecular formula could be C₅H₈O as it meets the weight criterion.
Step 2
State why there is a small peak at m/z = 87.
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Answer
The small peak at m/z = 87 indicates an isotopic peak, which is likely due to the presence of a ¹³C isotope. This suggests that one of the carbon atoms in molecule V is a ¹³C isotope, contributing an extra mass to the molecular ion.
