1.1 matter anything that has mass and takes up space The nature of chemistry The study of chemistry explores matter and its interactions. Matter is defined as anything that has mass and occupies space. Matter might include the food you eat, the cosmetics and grooming products you use, the battery in your cellphone, or the gasoline in your car engine. We encounter thousands of different chemicals every day. The potential applications of chemistry are therefore enormous. what Is Chemistry? It might be an interesting challenge to turn this question around and ask, “What isn’t chemistry?” Indeed, we are hard pressed to think of many things that do not relate to chemistry and its applications. Chemistry is often called the central science. Chemistry helps to connect the physical sciences (physics) and the life sciences (biology). Concepts in chemistry are often based on an understanding of the laws of physics. For example, the concept of ionic bonding is based on the understanding that opposite electrical charges attract one another. These chemical concepts can, in turn, be extended to help explore concepts in biology and environmental science. For example, once we understand what ions are and how they behave, we can apply this knowledge to the human body. This helps us understand and predict how many body systems work. The study of chemistry is subdivided into various branches. Inorganic chemistry, organic chemistry, nuclear chemistry, biochemistry, and physical chemistry are some of the different areas of chemistry. Chemists ask questions about the nature of matter and how it interacts. They design and conduct experiments, collecting evidence in an attempt to answer these questions. They analyze and evaluate data. Scientists eventually develop explanations that help them to understand what is taking place. These explanations may involve changes on a very small scale. Often scientists use models to help them visualize something that cannot be seen. Chemists may then make conclusions and develop theories, which they go on to test further. Chemists need to alternate between action in the macroscopic world (the “big” world) and thinking about the microscopic world (the “small” world) (Figure 1). lEARning TIP Conceptualizing in Chemistry Understanding concepts in chemistry often requires trying to visualize things that we cannot see. There are many ways you can help yourself to be better at this. Try using hands-on manipulative models, working with computer simulations, or drawing images on paper. experimenting theorizing Macroscopic world (large things) observing imagining Microscopic world (small things) measuring conceptualizing Figure 1 Chemistry involves moving back and forth between the macroscopic and the microscopic worlds. 8 Chapter 1 • Atomic Structure and the Periodic Table NEL The application of this knowledge leads to advances in technology. Science involves explaining observations about substances. Technology, however, often involves applying these explanations to produce something useful. The relationship between science and technology is complex. Sometimes science leads to technological advances, but at other times technology leads to scientific discovery. As an example, scientists discovered the substance Teflon by accident. Since then, Teflon has been used in many applications, such as a coating on cookware. You will learn more about Teflon later in this unit. Scientific discoveries and technological advances carry both risks and benefits. All scientists, engineers, and technicians must be aware of the risks and benefits related to their research. Long-term risks are often hard to foresee. For example, chlorofluorocarbons (CFCs) were once extensively manufactured and widely used. They were effective refrigerants, cleaning solvents, and propellants in aerosol cans. Consumers considered CFCs to be extremely beneficial substances. Then scientists discovered that CFCs deplete the stratospheric ozone layer. Safer alternative compounds have now replaced CFCs in most applications (Figure 2). Figure 2 Technology has partly solved the CFC problem by finding much safer propellants for spray cans. Chemistry at work Let’s examine a specific example of chemistry at work. You are probably familiar with three forms of carbon: charcoal, graphite, and diamond. In the late twentieth century, scientists discovered traces of a new form of carbon, C60. They found that pure C60 is an extremely stable substance that is able to withstand extremely high temperatures and that has low solubility in water. These experiments provided the chemists with empirical knowledge: knowledge that depends on observations. The chemists then pondered how they could explain these properties. This led them to propose models of the three-dimensional geometry of C60. The competition to isolate and identify C60 was intense as existing theories and new experiments worked hand in hand. Eventually, Harold Kroto, Robert Curl, and Richard Smalley were awarded the Nobel Prize in Chemistry in 1996 for their roles in its discovery. They proposed that its molecular shape resembles a soccer ball, with the carbon atoms forming the pentagons and hexagons on the surface of the sphere (Figure 3). Images of soccer balls and architectural domes helped chemists to imagine what these molecules might look like on a molecular scale. Knowledge based on ideas created to explain observations is known as theoretical knowledge. The discoverers named C60 “buckminsterfullerene,” after architect Richard Buckminster Fuller, who was famous for his work on geodesic domes. This rather long name is often shortened to “buckyball.” The family of carbon molecules with similar structures is known as “fullerenes.” A fullerene is any type of sphere, ellipsoid, or tube made entirely of carbon. (a) (b) (c) empirical knowledge knowledge that comes from investigation and observation theoretical knowledge knowledge that explains scientific observations WEB LInK In 2010 a Canadian astronomer discovered buckyballs in space, using NASA’s infrared telescope. To find out more about Jan Cami’s discovery, go T o n ElS on S C i En C E (d) Figure 3 (a) Pure C60 is a greyish powder. (b) Professor Harold Kroto proposed these models of buckyballs. (c) Vancouver Science World boasts a geodesic dome designed by Buckminster Fuller. (d) Chemists now have experimental evidence for the structure of C60. The suggested structure of a buckyball is a theory. A theory is an explanation of evidence obtained by observation, experimentation, and reasoning. It represents our best understanding about why something happens. It allows us to predict future events and apply knowledge to new situations. NEL theory an explanation or model based on observation, experimentation, and reasoning 1.1 The nature of Chemistry 9 UniT TASK BooKMARK Think of unlikely or serendipitous developments as you plan your green product for the Unit Task described on page 134. As more experimental work is done and as technology improves, theories evolve or are discarded. Before the mid-nineteenth century, people thought that heat was a substance. This substance, called “caloric,” appeared to flow from hot objects to cooler ones. Experiments eventually disproved this theory and it was discarded. As theories evolve, the body of scientific knowledge grows. For example, researchers are looking for possible uses of the C60 molecule in materials science, electronics, and health sciences. Buckyballs may be effective medicine delivery “cages.” Of course, chemistry does not always happen in a series of logical steps. Creativity, luck, and serendipity (chance) are often important. Everyday Chemistry Whether you are aware of it or not, you practice chemistry in your everyday life. You might be colouring your hair, cooking, gardening, exercising, or creating art. You are continually experimenting to achieve various objectives. Are you looking for that perfect shade of purple for your hair? Perhaps you are trying to figure out the ideal mix of fertilizers to yield the best crop of tomatoes. Maybe you are experimenting to find the best foods to eat before a cross-country running meet. You observe and measure things as you proceed. You make connections between what you changed and what happened. Often, you theorize about why things happen the way they do. You are already a budding chemist! IUPAC and the Scientific Community WEB LInK To find out more about the importance of the International Union of Pure and Applied Chemistry to the chemistry community, g o T o n El So n SCi E nCE Chemistry is a human endeavour performed by scientists all around the world. These scientists are driven by human emotions and actions: ambition, curiosity, wonder, competition, hope, and perseverance. There is the need for cooperation, trust, and governance in the scientific community. The International Union of Pure and Applied Chemistry (IUPAC) was established in 1919 in order to help regulate standards and procedures in chemistry. Specifically, IUPAC’s mission involves promoting the international aspects of chemistry and applying chemistry to the service of humanity. In so doing, IUPAC promotes the values, standards, and ethics of science. 1.1 Summary • Chemistry is the study of matter and its interactions. It is also a process for acquiring knowledge. It is a human endeavour. • Chemistry involves both experimenting in the macroscopic world and theorizing about the microscopic world. • The interplay between empirical (experimentally determined) knowledge and theoretical knowledge is critical in the study of chemistry. • The International Union of Pure and Applied Chemistry (IUPAC) sets rules and standards for chemists worldwide. 1.1 Questions 10 1. What isn’t chemistry? List as many things as you can think of that do not involve matter and its interactions. A 4. Explain the difference between empirical and theoretical knowledge, with examples. K/U 2. (a) Distinguish between science and technology. (b) Give a specific example of a scientific achievement and the technology that developed as a result of it. K/U A 5. There is a lot of interest in hydrogen-powered automobiles these days. Give an example of the science involved and an example of a technology involved. A 3. Sometimes it is hard to foresee the long-term effects of a chemical on the environment. K/U (a) Give an example of a chemical that has a negative environmental effect, and briefly describe that effect. (b) What is being done to reduce the negative effect? 6. (a) What does the acronym IUPAC stand for? (b) Why was this organization set up? (c) Do you think such an organization is necessary? Defend your position. K/U A Chapter 1 • Atomic Structure and the Periodic Table NEL