VCE Chemistry free practice questions with answers
Read question 1 and its full worked answer from paper 1 of our 20-paper VCE Chemistry set, then download the 4-page PDF. These are original practice questions, not official past papers. Page updated 3 November 2026.
The mass spectrum of hexane (C₆H₁₄) shows a molecular ion peak and fragment peaks at m/z 57, 43, 29. What is the m/z value of the molecular ion peak? (Use the integer masses C = 12, H = 1, O = 16.)
A 72
B 86
C 87
D 85
Correct answer: B — 86
- The molecular ion is the whole molecule with one electron removed, so m/z = relative molecular mass.
- M(C₆H₁₄) = 86, so the molecular ion peak is at m/z 86.
- Why the other options are wrong:
- A (72): used a fragment mass
- C (87): no extra hydrogen is added
- D (85): the electron lost has negligible mass; do not subtract 1
Mass spectrometry: the molecular ion peak (M+) gives the relative molecular mass; fragment peaks come from breaking bonds, with m/z = mass of the fragment ion.
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Questions about this sample
What is in the VCE Chemistry free sample?
The first 3 questions from paper 1 of the set, in the real exam layout, followed by the step-by-step worked answers. It is a 4-page PDF; this page shows question 1 with its answer.
How many full VCE Chemistry papers are there?
20 original papers for Victorian Year 12 students (VCE Units 3 and 4). Each is a full practice examination with Section A 30 multiple-choice, Section B 90 marks, 120 marks in all, 15 minutes reading time and 2 hours 30 minutes writing time, with a worked solution for every question. Papers start at A$15.99 and download instantly as a PDF.
Are these official past papers?
No. The sample is taken from our own original practice paper and is not an official past paper or affiliated with any exam authority.