Zinc sulfate

Key takeaways

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

Reference excerpt

Zinc sulfate is an inorganic compound with the formula ZnSO4. It forms hydrates ZnSO4·nH2O, where n can range from 0 to 7. All are colorless solids. The most common form includes water of crystallization as the heptahydrate, with the formula ZnSO4·7H2O. As early as the 16th century it was prepared on a large scale, and was historically known as "white vitriol".

Uses

Manufacturing The main application of the heptahydrate is as a coagulant in the production of rayon. It is also a precursor to the pigment lithopone. It is also used as an electrolyte for zinc electroplating, as a mordant in dyeing, and as a preservative for skins and leather.

Nutrition It is used as a dietary supplement to treat zinc deficiency and to prevent the condition in those at high risk. Side effects of excess supplementation may include abdominal pain, vomiting, headache, and tiredness. Zinc sulfate is used to supply zinc in animal feeds, fertilizers, toothpaste, and agricultural sprays. Zinc sulfate, like many zinc compounds, can be used to control moss growth on roofs. Zinc sulfate can be used to supplement zinc in the brewing process. Zinc is a necessary nutrient for optimal yeast health and performance, although it is not a necessary supplement for low-gravity beers, as the grains commonly used in brewing already provide adequate zinc. It is a more common practice when pushing yeast to their limit by increasing alcohol content beyond their comfort zone. Before modern stainless steel, brew Kettles, fermenting vessels and after wood, zinc was slowly leached by the use of copper kettles. A modern copper immersion chiller is speculated to provide trace amounts of zinc; thus care must be taken when adding supplemental zinc so as not to cause excess. Side effects include "...increased acetaldehyde and fusel alcohol production due to high yeast growth when zinc concentrations exceed 5 ppm. Excess zinc can also cause soapy or goaty flavors." Zinc sulfate is a potent inhibitor of sweetness perception for most sweet-tasting substances.

Medicine

It is also used together with oral rehydration therapy (ORT) and an astringent.

Production, reactions, structure

Zinc sulfate is produced by treating virtually any zinc-containing material (metal, minerals, oxides) with sulfuric acid. Specific reactions include the reaction of the metal with aqueous sulfuric acid:

Zn + H2SO4 + 7 H2O → ZnSO4·7H2O + H2 Pharmaceutical-grade zinc sulfate is produced by treating high-purity zinc oxide with sulfuric acid:

ZnO + H2SO4 + 6 H2O → ZnSO4·7H2O In aqueous solution, all forms of zinc sulfate behave identically. These aqueous solutions consist of the metal aquo complex [Zn(H2O)6]2+ and SO2−4 ions. Barium sulfate forms when these solutions are treated with solutions of barium ions:

ZnSO4 + BaCl2 → BaSO4 + ZnCl2 With a reduction potential of −0.76 V, zinc(II) reduces only with difficulty. When heated above 680 °C, zinc sulfate decomposes into sulfur dioxide gas and zinc oxide fume, both of which are hazardous. The heptahydrate is isostructural with ferrous sulfate heptahydrate. The solid consists of [Zn(H2O)6]2+ ions interacting with sulfate and one water of crystallization by hydrogen bonds. Anhydrous zinc sulfate is isomorphous with anhydrous copper(II) sulfate. It exists as the mineral zincosite. A monohydrate is known. The hexahydrate is also recognized.

Minerals As a mineral, ZnSO4·7H2O is known as goslarite. Zinc sulfate occurs as several other minor minerals, such as zincmelanterite, (Zn,Cu,Fe)SO4·7H2O (structurally different from goslarite). Lower hydrates of zinc sulfate are rarely found in nature: (Zn,Fe)SO4·6H2O (bianchite), (Zn,Mg)SO4·4H2O (boyleite), and (Zn,Mn)SO4·H2O (gunningite).

Safety

Zinc sulfate powder is an eye irritant. Ingestion of trace amounts is considered safe, and zinc sulfate is added to animal feed as a source of essential zinc, at rates of up to several hundred milligrams per kilogram of feed. Excess ingestion results in acute stomach distress, with nausea and vomiting appearing at 2–8 mg/kg of body weight. Nasal irrigation with a solution of zinc sulfate has been found to be able to damage the olfactory sense nerves and induce anosmia in a number of different species, including humans.

References

Illustrations

Worked examples

Example 1 — a first encounter with Zinc sulfate

Start with the simplest possible case. Write down what Zinc sulfate 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 Zinc sulfate 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 Zinc sulfate 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 Zinc sulfate

In research: Zinc sulfate 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 Zinc sulfate 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: Zinc sulfate is common in secondary-school and first-year university syllabi. It links to neighbouring topics Sulfates, Zinc compounds, so understanding it makes those chapters shorter.
In everyday life: Look for Zinc sulfate 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.

How to study Zinc sulfate in 20 minutes

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

Frequently asked questions

What is Zinc sulfate in simple terms?

Zinc sulfate is an inorganic compound with the formula ZnSO4. It forms hydrates ZnSO4·nH2O, where n can range from 0 to 7.

Why does Zinc sulfate 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 Zinc sulfate?

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 Zinc sulfate.