Understanding Chemical Analysis Chemical analysis involves techniques to determine the composition and purity of substances. This topic covers distinguishing pu...
Chemical analysis involves techniques to determine the composition and purity of substances. This topic covers distinguishing pure substances from mixtures, analyzing formulations, and using chromatography for separation and identification.
Pure substances have a fixed composition and unique set of properties, while mixtures consist of two or more substances physically combined. Formulations are mixtures designed for specific purposes, such as medicines, cleaning products, or fertilizers. Understanding their composition is crucial for quality control and safety.
Chromatography is a laboratory technique used to separate and identify components in a mixture based on their different rates of movement through a stationary phase. Key concepts include:
Problem: In a paper chromatography experiment, a dye moved 6 cm from the origin while the solvent front moved 9 cm. Calculate the Rf value.
Solution:
This topic also covers qualitative tests to identify common gases (hydrogen, oxygen, carbon dioxide, chlorine) and ions (cations: using flame tests and precipitation reactions; anions: carbonates, sulfates, halides).
An introduction to instrumental methods like flame emission spectroscopy for analyzing atomic emissions and identifying elements is included in the Higher Tier syllabus.