CHEMISTRY UNDERSTANDING SUBSTANCE AND MATTER including characteristic properties the use of chemical analysis and the physical and chemi cal changes that occur on the molecular level You will also investigate the classification of matter according to its chemical composition by element compound and mixture All matter consists of very small build ing blocks called atoms Chemists study how atoms interact with one another These inter actions affect everything they cause plants to grow fireflies to glow and bread dough to rise They govern how the food you eat is turned into energy and they are the reason that the leaves on some trees change color in the fall Why should you study chemistry People in many professions including medicine envi ronmental science and marine biology need a good working knowledge of chemistry But they are not the only ones Chemistry is very important in today's society To be an informed consumer you need to know what goes into the food you eat the beverages you drink and the clothes you wear Do you know how much fertilizer is needed to make your lawn green and how much is too much Do you know which household chemicals are safe to com bine and which are not Studying chemistry can help you answer these questions and many 10
INTRODUCTION others For this reason everyone could ben efit from knowing a little bit about chemistry and its underlying concepts Over time scientific knowledge builds on itself and the study of chemistry is no excep tion The discovery of the atom and the investigation of how atoms interact with one another have changed the world Chemists today strive to make the world a better place by studying new materials that can make life easier protect the environment and provide energy that humans can use In this volume you will be treated to an overview of the history and concepts you may encounter in an introductory chemis try course People use chemicals every day when they cook clean or take medications Chemical reactions happen all around you as you breathe eat or sit to read As your under standing of chemistry grows you will see that chemistry helps explain the world you live in and to varying degrees we are all chemists 11
CHAPTER 1 CHEMISTRY DEFINED NN he science of chemistry is the study of matter and the chemical changes J that matter undergoes Research in chemistry not only answers basic ques tions about nature but also affects people's lives Chemistry has been used for exam ple to make stronger metals to enrich soil for growing crops to destroy harmful bacteria and to measure levels of pollution in the environment It has also made pos sible the development of plastics synthetic fibers and new medicines Products produced by the chemical industry are an ordinary part of our daily lives The chemical industry converts raw materials such as water salt metals and minerals petroleum coal natural gas plant cellulose and starch and atmospheric gases into other products Some products require much more processing than others before they are subsequently used by manufactur ers and other industries Manufacturers use chemical products to make metal and 12
CHEMISTRY DEFINED A chemical company s researcher conducts experiments to recover traces of precious metals that are contained in the industrial water that was used during the recycling of electronics Marc Preel AFP Getty Images paper products wallboard pipe insulation and other construction materials polymers for electronic devices bottles films paints and other items and fibers for carpets and fabrics A few examples of other chemical products that are used by consumers include medicines dyes paints fertilizers shampoos detergents waxes perfumes cosmetics and flavorings 13
