Chemistry (III) Charts, School Education

Quick Answer: Chemistry (III) Charts are one set in a numbered series of chemistry charts for the classroom wall, centred on preparation processes such as making gases in the laboratory and manufacturing acids, drawn as labelled apparatus diagrams. They are used in secondary school chemistry.

Preparation Set-Ups Drawn Step by Step

Gas preparation diagrams are among the most examined drawings in school chemistry, and they are hard to copy correctly from a small textbook figure. A wall chart shows the complete set-up at a readable size: the reactants in a flask, the thistle funnel or dropping funnel, the delivery tube, any drying agent and the method of collection. Students can see why the thistle funnel dips below the liquid and why the delivery tube reaches the bottom or the top of the gas jar.

Common subjects include the laboratory preparation of oxygen, hydrogen, carbon dioxide, ammonia and hydrogen chloride, each linked to its collection method: over water for gases that are not very soluble, upward displacement of air for light gases such as ammonia, and downward displacement for dense gases such as carbon dioxide. Industrial manufacture of acids, such as sulfuric acid by the contact process, is usually drawn as a flow diagram of stages.

Because numbered series are split differently by different printers, check the titles in the (III) set against your syllabus before ordering.

Specifications

Applications

• Explaining a gas preparation practical before students assemble apparatus
• Teaching collection methods and why each suits a particular gas
• Industrial chemistry lessons on the contact process and similar flow sheets
• Practising neat labelled apparatus diagrams for practical records

Care & Handling

• Hang the Chemistry (III) charts in the theory area of the lab, not above reagent shelves or the fume cupboard, where acid fumes discolour paper.
• Keep them away from wash-up sinks and burner benches.
• Write each title on the back of its sheet so the right chart can be pulled out for each practical.

Why Choose LabEquip

School chemistry labs commonly buy the preparation charts alongside the Chemistry Lab Display Charts on apparatus and techniques. More titles are in Educational Charts, and orders go through the LabEquip contact page.

Frequently Asked Questions

Why is the thistle funnel dipped below the liquid in gas preparation?

If the end of the thistle funnel is above the liquid, the gas escapes through it instead of passing into the delivery tube. Keeping it below the surface forms a liquid seal.

How is the collection method chosen for a gas?

It depends on solubility and density. Slightly soluble gases such as oxygen and hydrogen are collected over water; very soluble gases are collected by displacement of air, upward for gases lighter than air such as ammonia and downward for denser ones such as hydrogen chloride.

Why is ammonia not dried with concentrated sulfuric acid?

Ammonia is a base and reacts with sulfuric acid to form ammonium sulfate. Quicklime (calcium oxide) is used instead, as the drying stage on an ammonia diagram usually shows.

What are the main stages of the contact process?

Sulfur is burnt to sulfur dioxide, which is purified and oxidised to sulfur trioxide over a vanadium pentoxide catalyst. The trioxide is absorbed in concentrated sulfuric acid to form oleum, which is diluted to give sulfuric acid.

How can the charts help with practical record books?

Students copy the set-up with a pencil and ruler, checking that each labelled part is present and that the gas jar is drawn the right way up. Teachers can then assess the diagrams against the chart.

Do the charts take the place of a demonstration?

No. The diagram shows the correct arrangement, while a supervised demonstration shows what the gas looks like, how it is tested and what precautions are needed. Studying the chart first makes the demonstration easier to follow.

Last Updated: September 2026