The Zimbabwe Secondary School Science Project (ZIM-SCI) developed student study guides, corresponding teaching guides, and science kits for a low-cost science course which could be taught during the first 2 years of secondary school without the aid of qualified teachers and conventional laboratories. This ZIM-SCI study guide is a two-part unit consisting of activities and experiments which focus on chemical concepts and basic laboratory skills. The ideas that matter is composed of small particles and that chemical energy is involved when these particles react are stressed throughout the unit. Activities and experiments in part 1 examine the breakdown of substances into smaller pieces (leading to the idea of a "smallest possible" particle) while those in part 2 lead to definitions of a chemical reaction, element, and compound. A self-test and summary section are included. Information to help students understand the scientific principles behind the activities and experiments is also included. (JN)