Book excerpt: Written by a former senior examiner, George Facer, this Edexcel A2 Chemistry Student Unit Guide is the essential study companion for Unit 4: Rates, Equilibria and Further Organic Chemistry. This book includes all you need to know to prepare for your unit exam: clear guidance on the content of the unit, with topic summaries, knowledge check questions and a quick-reference index, examiner's advice throughout, so you will know what to expect in the exam and will be able to demonstrate the skills required and exam-style questions, with graded student responses, so you can see clearly what is required to get a better grade.