13/06/2026
Science comes alive in the laboratory through observation, experimentation, and discovery. In this practical session, we explored two important areas of Chemistry: the identification of Copper(II) ions in a salt sample and the study of combustion reactions.
Salt Analysis: Test for Copper(II) Ions
Salt analysis is a fundamental laboratory technique used to identify the ions present in an unknown compound. To test for Copper(II) ions (Cu²⁺), the salt sample was dissolved in distilled water, producing a blue solution characteristic of copper compounds.
A few drops of sodium hydroxide solution were added, resulting in the formation of a light blue precipitate of copper(II) hydroxide, confirming the presence of Copper(II) ions. When excess ammonia solution was added, the precipitate dissolved to form a deep blue solution, providing further confirmation of Copper(II) ions in the sample.
Combustion Reaction
Combustion is a chemical process in which a substance reacts rapidly with oxygen, releasing heat and often light energy. During the experiment, a combustible material was ignited in the presence of oxygen.
Steps in the Combustion Process:
1. Preparation of the combustible substance.
2. Exposure to a sufficient oxygen supply.
3. Ignition using a heat source.
4. Observation of flame colour, heat production, and gaseous products.
5. Recording and interpretation of results.
The experiment demonstrated that combustion is an exothermic reaction, releasing energy into the surroundings. Complete combustion produced carbon dioxide and water vapour, while incomplete combustion can produce carbon monoxide and soot.
Conclusion
This practical exercise successfully demonstrated the identification of Copper(II) ions through characteristic chemical tests and highlighted the principles of combustion reactions. Such experiments enhance students' understanding of analytical chemistry, chemical reactions, and the importance of laboratory investigation in scientific learning.
Science is not just theory—it is discovery through observation, experimentation, and evidence.
