Ergänzungsprüfung Chemie at the VWU in Vienna: three questions, how to prepare and a worked problem

The supplementary chemistry exam, Ergänzungsprüfung Chemie, is assigned by the university you apply to with a foreign school-leaving certificate if your school chemistry falls short of what the programme needs. Whether you've been assigned it is stated in your admission decision, the Zulassungsbescheid.

The exam is oral, and the VWU, the preparatory course of Vienna's universities, has spelled out in detail which areas the questions come from and how much of each you need to answer. The VWU runs a chemistry course, but you can sit the exam without it: the course posts sample questions for each section, a list of key terms and a formula collection, and you can prepare on your own with them.

Who gets assigned the chemistry exam

The university draws up the list of supplementary exams for a specific programme and a specific school certificate. For medicine in Vienna, the VWU prepares you for five exams: German, biology, chemistry, physics and mathematics. Which of them you're assigned is stated in your own admission decision.¹

How the chemistry exam works

You get 20 minutes to prepare, and the answer itself lasts 10 minutes. There are three questions, and each must be answered to at least 50%, so a strong answer to one question won't make up for a weak answer to another. The VWU doesn't say how this turns into a grade from 1 to 4.²

The sections, Abschnitte, are the four parts of the VWU chemistry course, and the problem sets on the course website are split the same way. Answer so that your reasoning can be followed: the examiners ask you to explain step by step. The basics, meaning the periodic table, reaction equations, key terms and applying formulas, are taken as known.²

You answer in front of a three-member commission: your examiner, another VWU teacher and a university representative, who chairs it.³

What you're given in the chemistry exam

You bring your own non-programmable calculator. The periodic table, formula collection and tables are provided at the exam.²

A worked problem from the VWU problem set

This problem comes from the course's problem set for section 3 in the 2026 summer semester, on buffers. One litre of buffer solution contains 0.3 mol/l acetic acid and 0.2 mol/l acetate ions. Find the pH of this solution and the pH after adding 2 g of KOH.⁴

A buffer is calculated with the Henderson–Hasselbalch equation, which is also on the course's list of key terms. With $p{K}_a=4.75$ for acetic acid we get $\text{pH}=4.75+\lg \frac{0.2}{0.3}\approx 4.57$.

Next, the KOH. Its molar mass is about 56.11 g/mol, so 2 g is roughly 0.0356 mol. The hydroxide ions turn part of the acid into acetate: $0.3-0.0356\approx 0.264$ mol of acid remains, and acetate rises to $0.2+0.0356\approx 0.236$ mol. Then $\text{pH}\approx 4.75+\lg \frac{0.236}{0.264}\approx 4.70$.

The pH has barely moved: the buffer absorbs the added base because the acetic acid neutralises it. In the exam you explain this in words alongside the calculation, so the path of your answer can be followed.

Chemistry exam dates, registration and retakes

Oral exams in all subjects take place in the same weeks: the next ones from 30 November to 3 December 2026, then from 25 to 29 January and from 15 to 19 March 2027. Registration for the November session runs from 16 to 29 October 2026 until 12:00 through the VWU portal. The fee is €46 per attempt, you can retake the exam up to four times, and you can withdraw your registration up to one week before the first day of the oral exams. If this is your last exam, the November session won't work for that: it falls after the universities' admission deadline, so you can no longer move into a regular degree programme in the 2026 winter semester.³

How to prepare for the chemistry exam

1. Download the list of key terms, the Stichwortliste, and the formula collection from the VWU chemistry course page. You need to be able to explain every term in your own words and apply it: the list includes, for example, Hund's rule, Le Chatelier's principle, the Nernst equation, the hybridisation of carbon, Markovnikov's rule and chirality.⁵
2. For the second and third questions, work through the problem sets for sections 3 and 4 from the 2026 summer semester. There's no recent set for the first question: for sections 1 and 2 the website has the questions from the course's 2018 bonus tests, so prepare with those.
3. Solve every problem with the full working and units, as the problem set requires, then explain the solution out loud, as in the exam.
4. Split your time equally between the three areas.

How the other supplementary exams and the preparatory course work is covered in the VWU overview.

Sources

· 5 checked 01.10.2026

1. 1Vorstudienlehrgang, Medizinische Universität Wien · checked 01.10.2026
2. 2Informationen zur Ergänzungsprüfung Chemie (mündlich) · checked 01.10.2026
3. 3Ergänzungsprüfungen — Vorstudienlehrgang der Wiener Universitäten · checked 23.09.2026
4. 4Übungsbeispiele Abschnitt 3, Sommersemester 2026 · checked 01.10.2026
5. 5Chemie am VWU: Allgemeine Informationen · dated 21.06.2026, checked 01.10.2026