AS 91162 Carry out procedures to identify ions present in solution 3 credits internally assessed. Practical component with written answers. This topic covers: Qualitative – definitions of solubility Solubility rules Identifying ions Balancing ionic equations Complex ions Balancing complex ion equations

What are ions? Made up of +ve and -ve ions +ve -ve Cation Anion Held together by the electrostatic attraction between the +ve and -ve charges. Overall ionic compounds are neutral.

What’s a solution? A liquid mixture of solute (solid) dissolved in solvent (liquid). Note: Most of the H+ and OH- combine to form H2O.

Question: How do we know what ions are present in a solution?

So what’s the ‘solution’ to this problem? Taste the chemicals? See the chemicals? Feel the chemicals? Try putting other chemicals to see if it reacts? Or just ask whoever made the chemicals?

Quality not quantity. This type of experiment is called Qualitative analysis which is about finding out what is there. Qualitative – an analysis using qualities such as colour change, smell or precipitation (cloudiness) Quantitative – an analysis using quantities like volume, mass or amount

Practical It turns out that many ions are colored (especially the metal ones) and is easily identifiable, now lets observe some chemicals and note down the color of them.