chemistry

Nonvolatile acid

Nonvolatile acid 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 Nonvolatile acid rather than just read about it. In short: A nonvolatile acid (also known as a fixed acid or metabolic acid) is an acid produced in the body from sources other than carbon dioxide, and is not excreted by the lungs. They can be produced from an incomplete metabolism of carbohydrates, fats, and proteins.

Key takeaways

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

Reference excerpt

A nonvolatile acid (also known as a fixed acid or metabolic acid) is an acid produced in the body from sources other than carbon dioxide, and is not excreted by the lungs. They can be produced from an incomplete metabolism of carbohydrates, fats, and proteins. All acids produced in the body are nonvolatile except carbonic acid, which is the sole volatile acid. Common nonvolatile acids in humans are lactic acid, phosphoric acid, sulfuric acid, acetoacetic acid, and beta-hydroxybutyric acid. Humans produce about 1–1.5 mmoles of H+ per kilogram per day. Most nonvolatile acids are excreted by the kidneys. Lactic acid is usually completely metabolized by the body, and is thus not excreted from the body.

Reactions The following reactions result in nonvolatile acids:

sulfur-containing amino acid oxidations: e.g. methionine or cysteine → urea + CO2 + H2SO4 → 2H+ + SO2−4 phosphorus-containing compound metabolism → H3PO4 → H+ + H2PO−4 cationic amino acid oxidation: e.g. lysine or arginine → urea + CO2 + H2O + H+ Non-metabolizable organic acid production: HA → H+ + A− Incomplete metabolism of carbohydrates, fats, and proteins → e.g. lactic acid or keto-acids

Worked examples

Example 1 — a first encounter with Nonvolatile acid

Start with the simplest possible case. Write down what Nonvolatile acid 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 Nonvolatile acid 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 Nonvolatile acid 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 Nonvolatile acid

In research: Nonvolatile acid 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 Nonvolatile acid 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: Nonvolatile acid is common in secondary-school and first-year university syllabi. It links to neighbouring topics Acid–base physiology, so understanding it makes those chapters shorter.
In everyday life: Look for Nonvolatile acid 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 Nonvolatile acid in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Nonvolatile acid 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 Nonvolatile acid out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Nonvolatile acid in simple terms?

Why does Nonvolatile acid 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 Nonvolatile acid?

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 Nonvolatile acid.