What makes propane such an efficient, clean-burning fuel? How can soot and diamond be so different in appearance yet so chemically similar? Chemistry has the answer to these questions and many more. Understanding chemistry is the key to understanding the world as we know it.
The study of chemistry can be organized into distinct branches that emphasize subsets of chemical concepts. Analytical chemistry seeks to determine the exact chemical compositions of substances. Biochemistry is the study of chemicals found in living things such as DNA and proteins.
Inorganic chemistry studies substances that do not contain carbon. Organic chemistry studies carbon-based substances. Physical chemistry is the study of the physical properties of chemicals. Others are not so obvious. Because we move so easily through air, we sometimes forget that it, too, is matter.
Chemistry is one branch of science. Science is the process by which we learn about the natural universe by observing, testing, and then generating models that explain our observations. Thus, chemistry is the study of matter, biology is the study of living things, and geology is the study of rocks and the earth.
Mathematics is the language of science, and we will use it to communicate some of the ideas of chemistry. Although we divide science into different fields, there is much overlap among them.
For example, some biologists and chemists work in both fields so much that their work is called biochemistry. Similarly, geology and chemistry overlap in the field called geochemistry. As our understanding of the universe has changed over time, so has the practice of science. Chemistry in its modern form, based on principles that we consider valid today, was developed in the s and s. Before that, the study of matter was known as alchemy and was practiced mainly in China, Arabia, Egypt, and Europe.
Alchemy was a somewhat mystical and secretive approach to learning how to manipulate matter. Practitioners, called alchemists, thought that all matter was composed of different proportions of the four basic elements—fire, water, earth, and air—and believed that if you changed the relative proportions of these elements in a substance, you could change the substance. Alchemists used symbols to represent substances, some of which are shown in the accompanying figure.
This was not done to better communicate ideas, as chemists do today, but to maintain the secrecy of alchemical knowledge, keeping others from sharing in it.
In spite of this secrecy, in its time alchemy was respected as a serious, scholarly endeavor. Chemistry is the study of matter , analysing its structure, properties and behaviour to see what happens when they change in chemical reactions. As such, it can be considered a branch of physical science, alongside astronomy, physics and earth sciences including geology. An important area of chemistry is the understanding of atoms and what determines how they react.
It turns out reactivity is often largely mediated by the electrons that orbit atoms and the way these are exchanged and shared to create chemical bonds. Chemistry has now split into many branches. For instance, analytical chemists might measure the traces of compounds in ancient pottery to discern what people were eating thousands of years ago. Organic chemistry, the study of compounds which contain carbon, connects up molecules in new ways to build and analyse an array of materials, from drugs to plastics to flexible electronics.
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