Compounds Demonstrations

See also: Organic Chemistry

Compounds are substances formed when atoms of different elements join together in fixed proportions. This category introduces the idea of chemical bonding, the distinction between compounds and mixtures, and the unique properties compounds possess. Understanding compounds is a key step in explaining the diversity of substances found in nature and technology.

Demonstration	Materials	Difficulty	Safety	Summary
Carbon Sugar Snake	★★★	★★☆	★★★	A mixture of sugar and baking soda is ignited with lighter fluid on a sand base, producing an expanding black "snake" of carbon and sodium carbonate as gases from decomposition push the solid upward.
Golden Rain	★★☆	★★☆	★★☆	Lead nitrate reacts with potassium iodide to form a bright yellow precipitate of lead iodide. When heated, the precipitate dissolves in hot water, but as the solution cools, thin hexagonal crystals fall out of solution like golden flakes, creating the “golden rain” effect.
Ionic Cut and Match	★☆☆	★☆☆	★☆☆	Students cut out cards showing cations, anions, and compound formulas, then match them correctly. This reinforces naming rules and helps students practice writing and recognizing ionic compounds.
Making Marshmallow Molecules	★☆☆	★☆☆	★☆☆	This activity uses colored marshmallows and toothpicks to model atoms, molecules, and compounds. By assembling marshmallows to represent different elements and connecting them with toothpicks as covalent bonds, students can visualize how atoms combine to form molecules and chemical structures.
Solid Lead Nitrate and Potassium Iodide	★★☆	★☆☆	★★☆	When lead nitrate and potassium iodide powders are combined and shaken, they undergo a double displacement reaction to produce yellow lead iodide.
Sugar and Sulfuric Acid Carbon Snake	★★☆	★★☆	★★☆	Concentrated sulfuric acid is added to sugar, causing a vigorous dehydration and oxidation reaction. The mixture heats up and produces steam, carbon dioxide, and a growing black column of carbon that resembles a snake rising from the container.
Thermal Decomposition of Ammonium Chloride	★★☆	★☆☆	★★☆	Ammonium chloride, when heated, undergoes decomposition into hydrogen chloride and ammonia gasses, before reforming when cool. The process appears similar to sublimation and deposition.

Materials
★☆☆ Easy to get from supermarket or hardware store
★★☆ Available in most school laboratories or specialist stores
★★★ Requires materials not commonly found in school laboratories

Difficulty
★☆☆ Can be easily done by most teenagers
★★☆ Available in most school laboratories or specialist stores
★★★ Requires a more experienced teacher

Safety
★☆☆ Minimal safety procedures required
★★☆ Some safety precautions required to perform safely
★★★ Only to be attempted with adequate safety procedures and trained staff