Chemistry: A Science for the 21st Century

What is chemistry?

Chemistry is the study of matter and the changes that occur in it. It is often considered the central science because the basic knowledge of chemistry is indispensable for students of biology, physics, geology, ecology, and many other disciplines. In fact, chemistry is a central part of our lifestyle; without it, our lives would be shorter in what we would call primitive conditions, without cars, electricity, computers, compact discs, and many other modern conveniences.

Although chemistry is an ancient science, its modern foundations date back to the 19th century when intellectual and technological advances allowed scientists to separate substances into their components and, therefore, explain many of their physical and chemical characteristics. The rapid development of increasingly sophisticated technology during the 20th century has provided us with ever greater means to study what is imperceptible to the naked eye. The use of computers and special microscopes, for example, allows chemists to analyze the structure of atoms and molecules (the fundamental units on which the study of chemistry is based) and design new substances with specific properties, such as drugs and environmentally friendly consumer products.

At the beginning of the 21st century, it is worth asking what role chemistry will play in this century. It is almost certain that chemistry will maintain a fundamental role in all areas of science and technology. Before delving into the study of matter and its transformation, let us consider some frontiers that chemists are currently exploring.

Where is chemistry involved?

Health and Medicine

Three significant achievements in the 20th century have enabled the prevention and treatment of diseases. These are public health measures that established healthcare systems to protect numerous people against infectious diseases; anesthesia in surgery, which has enabled doctors to cure potentially fatal diseases like appendicitis; and the advent of vaccines and antibiotics, which made it possible to prevent diseases caused by microorganisms. Gene therapy appears to be the fourth revolution in medicine. Genes are the basic units of inheritance. There are thousands of known diseases, including cystic fibrosis and hemophilia, caused by inherited damage to a single gene. Many other conditions, such as cancer, heart diseases, AIDS, and arthritis, result to some extent from alterations in one or more genes related to the body's defense systems. In gene therapy, a specific healthy gene is inserted into the patient's cells to cure or alleviate these disorders. To perform these procedures, the doctor must have a solid understanding of the chemical properties of the molecular components involved. The decoding of the human genome, which comprises all the genetic material in our bodies and plays an essential role in gene therapy, is primarily based on chemical techniques.

Chemists in the pharmaceutical industry research potent drugs with few or no adverse effects for the treatment of cancer, AIDS, and many other diseases, as well as drugs to increase the success rate of organ transplants. On a broader scale, improving our understanding of the aging process will lead to a longer and healthier life expectancy for the inhabitants of the planet.

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Energy and the Environment

Energy is a byproduct of many chemical processes, and as the demand for energy continues to rise, both in industrialized countries like the United States and in developing nations like China, chemists are actively seeking new sources of energy. Currently, the main sources of energy are fossil fuels (coal, oil, and natural gas). Estimated reserves of these fuels will last another 50 to 100 years at the current rate of consumption, making it urgent to find alternative sources.

Solar energy appears to be a viable source of energy for the future. Each year, the Earth's surface receives around 10 times the energy contained in all known reserves of coal, oil, natural gas, and uranium combined from sunlight. However, much of that energy is "wasted" as it is reflected back into space. Over the last 30 years, intensive research activities have shown that solar energy can be effectively utilized in two ways. One is its direct conversion into electricity using devices called photovoltaic cells. The other involves using solar light to obtain hydrogen from water, which is then used to power a fuel cell to generate electricity. Although advances have been made in the scientific process of converting solar energy into electricity, the technology has not yet improved to the point where it is economically feasible to produce electricity on a large scale. However, it has been predicted that by 2050, solar energy will meet more than 50% of energy needs.

Another potential source of energy is nuclear fission, although the future of the nuclear industry in the United States and other countries is uncertain due to environmental concerns about the radioactive waste produced by fission processes. Chemists can help improve the ultimate disposal of nuclear waste. Nuclear fusion, the process that occurs in the Sun and other stars, generates vast amounts of energy without producing many hazardous radioactive wastes. In another half-century, nuclear fusion is likely to become a significant source of energy.

The production and use of energy are closely related to the quality of the environment. A significant drawback of burning fossil fuels is the production of carbon dioxide, which is one of the greenhouse gases (those that promote global warming), as well as sulfur dioxide and nitrogen oxides, which cause acid rain and smog. (The use of solar energy does not have these harmful effects on the environment.) The use of fuel-efficient cars and more effective catalytic converters should allow for a substantial reduction in harmful automotive emissions and an improvement in air quality in areas with heavy traffic. Furthermore, the use of long-lasting battery-powered electric cars and hybrid vehicles, powered by both batteries and gasoline, should help minimize atmospheric pollution.

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Materials and Technology

The research and development of chemistry in the 20th century have generated new materials that have had a profound impact on the quality of life and have helped advance technology in various ways. A few examples include polymers (including rubber and nylon), ceramics (used in kitchen utensils), liquid crystals (such as those in electronic displays), adhesives (used in sticky notes), and coating materials (such as latex paints).

What does the near future hold for us? One very likely development is the use of high-temperature superconducting materials. Electricity is conducted through copper wires, which are not perfect conductors. As a result, nearly 20% of electrical energy is lost as heat between the power plant and homes or offices, which constitutes a massive waste. Superconductors are materials devoid of electrical resistance, and therefore, they conduct electricity without energy loss. Although the phenomenon of superconductivity at very low temperatures (over 400 degrees Fahrenheit below the freezing point of water) has been known for over 90 years, a significant breakthrough in the mid-1980s revealed that it is possible to fabricate materials that act as superconductors at or near room temperature. Chemists have played a role in designing and synthesizing promising new materials in this quest. In the next 30 years, we will see large-scale applications of high-temperature superconductors in areas such as magnetic resonance imaging (MRI), maglev trains, and nuclear fusion.

If there were one technological advancement that has shaped our lives more than any other, it would have to be computers. The "engine" driving the computer revolution is the microprocessor, the tiny silicon chip that has served as the basis for numerous inventions, such as laptops and fax machines. The efficiency of microprocessors is judged by how fast they perform mathematical operations, such as addition. Progress has been so rapid that the speed of microprocessors has doubled every 18 months since their inception. The quality of a microprocessor depends on the purity of the silicon chip and the ability to add the necessary amount of other substances, where chemists play a significant role in silicon chip research and development. In the future, scientists will begin to explore the prospects of "molecular computing," meaning replacing silicon with molecules. The advantages lie in the fact that certain molecules can respond to light, not electrons, which would lead to optical computers instead of electronic ones. Through appropriate genetic engineering, scientists can synthesize these molecules with microorganisms, replacing large factories. Optical computers would also have much greater storage capacity than electronic ones.

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Food and Agriculture

How to feed the growing world population? In poor countries, nearly 80% of the workforce is engaged in agricultural production, and half of the average family budget is spent on food. This places a tremendous burden on the resources of these nations. Factors affecting agricultural production include soil fertility, insects and diseases that damage crops, and other plants competing for nutrients. In addition to irrigation, farmers turn to fertilizers and pesticides to improve crop productivity. Since the 1950s, treating pest-infested crops has sometimes involved the indiscriminate application of potent chemical compounds. Such measures have often had serious harmful effects on the environment. Even the excessive use of fertilizers is detrimental to soil, water, and air.

In order to meet the food demand in the 21st century, innovative strategies must be devised for agriculture. It has already been demonstrated that biotechnology can be used to obtain higher-yielding and better-quality crops. These techniques have been applied to many agricultural products, not only to enhance their production but also to achieve multiple annual harvests. For example, it is known that certain bacteria produce a toxin harmful to leaf-eating caterpillars. The inclusion of the gene encoding the toxin in cultivated plants provides them with protection against these pests, eliminating the need for pesticides. Researchers have also found ways to disrupt the reproduction of insect pests. Insects communicate with each other by emitting special molecules called pheromones, to which they react. The identification and synthesis of pheromones involved in mating allow for interference in the normal reproductive cycle of common pests, such as inducing premature reproductive mating in insects or tricking females into mating with sterile males. Furthermore, chemists can devise ways to increase the production of environmentally less harmful fertilizers and substances that selectively eliminate harmful weeds.

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Chemistry in Everyday Life

Compared to other disciplines, there's often the idea that chemistry is more challenging, at least at the basic level. This perception is justified to some extent; for example, it is a field with highly specialized vocabulary. However, even if we have never been interested in chemistry or actively engaged with it, we are already familiar with the subject much more than we realize. In everyday conversations, we hear words related to chemistry, although not necessarily used in the scientifically correct sense. Examples include terms like "electronics," "quantum leap," "equilibrium," "catalyst," "chain reaction," and "critical mass." Furthermore, if you cook, then you are a practicing chemist! Thanks to experience in the kitchen, you know that oil and water don't mix, and that if you boil water on the stove, there comes a point when it evaporates completely. You also apply the principles of chemistry and physics when using baking soda in making bread, a pressure cooker to shorten cooking times for stews, adding meat tenderizer to a dish, squeezing lemon over pear slices to prevent them from turning brown, or adding vinegar to the water when boiling eggs. Every day, we observe these changes without thinking about their chemical nature.

What is the purpose of chemistry?

The purpose of chemistry is to think like a chemist, to be able to see the macroscopic world, what we can directly see and touch, and visualize the particles and phenomena of the microscopic world that we cannot experience without modern technology and our imagination. At first, it's normal to get confused between the microscopic and macroscopic worlds. Just keep in mind that data from chemical research often come from observations of large-scale phenomena, even though the explanations usually lie in the invisible and imaginary microscopic world of atoms and molecules.

In other words, chemists often see something (in the macroscopic world) and think about something else (in the microscopic world). For example, when observing rusted nails, a chemist would think about the basic properties of individual iron atoms and how these units interact with other atoms and molecules to produce the observed change.