Chapter Two: Chemical analysis

About this lesson

This unit introduces students to chemical analysis, covering both qualitative and quantitative methods. It begins by reviewing foundational concepts such as mole, molar mass, number of moles, gas volume at STP, density, molar concentration, and mass percentages. The text then explains the importance of chemical analysis in fields like medicine, agriculture, industry, and the environment, and distinguishes between qualitative analysis (identifying constituents) and quantitative analysis (estimating percentages). For qualitative analysis, it details the detection of acidic radicals (anions) grouped by their reactions with dilute hydrochloric acid, concentrated sulphuric acid, and barium chloride solution, providing specific tests and confirmatory reactions for ions like carbonate, bicarbonate, sulphite, sulphide, thiosulphate, nitrite, chloride, bromide, iodide, nitrate, phosphate, and sulphate. It also covers the identification of basic radicals (cations) through group reagents, with examples like copper(II), aluminium, iron(II), iron(III), and calcium, including confirmatory tests and flame tests. For quantitative analysis, the unit explains volumetric analysis (titration) using neutralization reactions, with worked examples calculating concentrations, and gravimetric analysis via volatilization and precipitation methods, including calculations for water of crystallization and mass of analyte. The unit concludes with evaluation questions testing these concepts.