chemistry

Hans von Pechmann

Hans von Pechmann is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Hans von Pechmann rather than just read about it. In short: Freiherr Hans von Pechmann (1 April 1850 – 19 April 1902) was a German chemist, renowned for his discovery of diazomethane in 1894. Pechmann condensation and Pechmann pyrazole synthesis.

Key takeaways

Hans von Pechmann belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Hans von Pechmann to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Hans von Pechmann from memory before moving on to harder problems.

Reference excerpt

Freiherr Hans von Pechmann (1 April 1850 – 19 April 1902) was a German chemist, renowned for his discovery of diazomethane in 1894. Pechmann condensation and Pechmann pyrazole synthesis. He also first prepared 1,2-diketones (e.g., diacetyl), acetonedicarboxylic acid, methylglyoxal and diphenyltriketone; established the symmetrical structure of anthraquinone. Von Pechmann also produced the first example of solid polyethylene serendipitously in 1898, via the decomposition of diazomethane.

Life Von Pechmann was born in Nuremberg, the only son of a doctor, who was also named Hans. The von Pechmanns had distinguished themselves as soldiers; in 1702, von Pechmann's ancestor Martin Günther von Pechmann, a general of artillery in the Bavarian army, had been raised to the rank of a baron of the Holy Roman Empire by Leopold I. After studying with Heinrich Limpricht at the University of Greifswald he became professor at the Ludwig-Maximilians-Universität München until 1895. He was professor at the University of Tübingen from 1895 until his death. He killed himself by taking cyanide, aged 52.

Works Volhard's Anleitung zur Qualitativen chemischen Analyse . Chemisches Labolatorium des Staates, Munich 9th & 10th ed. 1901 Digital edition by the University and State Library Düsseldorf Anleitung zur quantitativen Analyse nach Cl. Zimmermann: zum Gebrauche im chemischen Laboratorium des Staates zu München. Chemisches Laboratorium des Staates, Munich 10th ed. 1901 Digital edition by the University and State Library Düsseldorf

See also German inventors and discoverers

Notes

References

Partington, J. R. A History of Chemistry. Macmillan: 1964; vol. 4, p. 838-839.

Illustrations

Worked examples

Example 1 — a first encounter with Hans von Pechmann

Start with the simplest possible case. Write down what Hans von Pechmann claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Hans von Pechmann before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Hans von Pechmann ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Hans von Pechmann

In research: Hans von Pechmann appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Hans von Pechmann in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Hans von Pechmann is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1850 births, 1902 deaths, 1902 suicides, so understanding it makes those chapters shorter.
In everyday life: Look for Hans von Pechmann outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Hans von Pechmann in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Hans von Pechmann means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Hans von Pechmann out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Hans von Pechmann in simple terms?

Freiherr Hans von Pechmann (1 April 1850 – 19 April 1902) was a German chemist, renowned for his discovery of diazomethane in 1894. Pechmann condensation and Pechmann pyrazole synthesis.

Why does Hans von Pechmann matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Hans von Pechmann?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Hans von Pechmann.