Units, Symbols & Terminology Used

Chemical names and formulae: as far as is practically possible, the IUPAC conventions for the naming of chemical compounds have been used. Inorganic compounds are usually named according to the Stock notation—the oxidation number given in Roman numerals after the name of the element, e.g. ferrous becomes iron(II).

Quantities: throughout the book, the concentration of solutions is expressed in moles per cubic decimetre unless otherwise stated. At the risk of becoming persona non grata with some readers, I have opted to abbreviate the units ‘mol dm⁻³’ to M, firstly because this is what is used in the ‘real world’ where our students will one day work, and secondly because it is less cumbersome. Similarly, I have opted to use millilitres (mL) to express volumes of liquids and solutions, rather than the SI unit cm³. Those students following courses with an examination component should be encouraged to use the units stated in their course specification. When a quantity is described as ‘an aliquot’ or ‘exactly’, a pipette or burette should be used to deliver that quantity; otherwise a measuring (graduated) cylinder is sufficient.

The practical activities given in this book have been developed to use the lowest concentration of reagents possible. However, an essential part of training in chemistry is to learn how to safely handle chemicals. For schools and colleges in the UK, CLEAPSS (www.cleapss.org.uk) provides invaluable information on chemical safety in the form of their Hazcards. It is the responsibility of all those who use the practical information in this book to conduct their own risk assessment for each activity.

• Always perform your own risk assessment for a practical activity—don’t rely on other people's advice, especially if you have a medical condition such as asthma. Make sure you are familiar with hazard warning symbols.

• Always wear personal protective equipment (PPE) which normally includes a buttoned-up laboratory coat and safety goggles. Ordinary glasses will not provide sufficient protection for the eyes and contact lenses should not be worn during practical sessions. Open-toed sandals or very high heels should not be worn in the laboratory.

• Always label all glassware that contains solutions with the name of the reagent and its concentration. Do not remove more of the solution from the storage bottles than is required.

• When heating solutions with an open flame (Bunsen burner) make sure all long hair is tied back and that no flammable liquids are in the laboratory. Adjust the Bunsen to give a luminous flame when not in use.

• Never force pipettes into a pipette filler. The pipette should be held a few centimetres from the upper-most end and gently inserted into the filler.

Under the CLP regulations (Classification, Labelling and Packaging of Substances and Mixtures) introduced in January 2009, a new set of hazard warning symbols were introduced to replace the existing symbols. It is likely that both will be in use for some time as many older stocks of chemicals may still be used in teaching laboratories.