Chemistry

Chemistry is the scientific study of the properties and behavior of matter. It is a physical science that looks at how matter is made, how it is put together, and how it changes during reactions with other substances. Chemistry also explores the nature of chemical bonds in chemical compounds.

Chemistry sits between physics and biology. It is often called the central science because it helps us understand many other scientific areas. For example, chemistry explains how plants grow, how rocks form, how the air stays clean, how medicines work in our bodies, and even how we can collect important clues from a crime scene.

Chemistry has been around for a very long time, under different names. Over the years, it has grown into many special areas of study. These areas work together and help create new fields of study. The ideas from chemistry are used a lot in industries to make useful products for people.

Etymology

Main article: Etymology of chemistry

The word chemistry started from changes made during the Renaissance to the word alchemy. Alchemy was an older practice that included parts of chemistry, metallurgy, philosophy, astrology, astronomy, mysticism, and medicine. People who practiced alchemy, called alchemists, were especially famous for trying to change lead and other metals into gold, but they also asked many questions that are still important in chemistry today.

The word alchemy itself comes from the Arabic word al-kīmīā. This word might have come from ancient Egypt, because it is linked to the Ancient Greek word χημία, which comes from Kemet, the old name for Egypt. Another idea is that al-kīmīā means “cast together.”

Modern principles

The current way we understand how tiny parts of matter work is called the quantum mechanical model. Chemistry starts with studying tiny pieces called elementary particles, atoms, molecules, and other things made of matter like metals, crystals, and liquids or gases. These tiny pieces can change and react with each other, forming new substances. Chemists study these changes in special rooms called chemistry laboratories.

In a chemistry lab, scientists use special glass tools, but they can also do experiments without them. When substances change into new substances, it’s called a chemical reaction. This happens because the tiny parts called electrons move and change how they stick together. We can write these reactions down using symbols called chemical equations.

Chemists also study how much energy is involved in these changes. They look at how substances are built, how they change from one state to another like solid to liquid, and how they react. Some important ideas in chemistry include how matter is made, what it’s made of, and how it behaves under different conditions.

History

Main article: History of chemistry

For a chronological guide, see Timeline of chemistry.

The history of chemistry goes back a long way, from ancient times to today. For thousands of years, people have used methods that later became part of chemistry. They learned how to get metals from ores, make pottery and glazes, brew beer and wine, get useful things from plants, turn fat into soap, create glass, and make mixtures like bronze.

Before chemistry, there was a practice called alchemy. Alchemists didn’t understand matter fully, but they did experiments and wrote down what happened. One important alchemist, Robert Boyle, helped make chemistry a serious subject with his book The Sceptical Chymist in 1661.

What made chemistry different from alchemy was the use of the scientific method. Chemists carefully measured and observed things. Antoine Lavoisier was key in making chemistry a real science. He created a rule about the conservation of mass, and his work connects to the history of thermodynamics, especially through Willard Gibbs.

The idea of what chemistry means has changed over time. Early scientists thought about basic parts of matter. Later, it became the study of substances and how they change.

Ancient people, like the Egyptians, Babylonians, and Indians, knew a lot about practical uses but didn’t have a full theory. The ancient Greeks, like Aristotle, thought everything was made from fire, air, earth, and water. They also had ideas about tiny parts of matter, called atomism, from thinkers like Democritus.

In the Middle East, people mixed science with magic, trying to turn metals into gold or find a potion for long life. Later, this spread to Europe. Important Muslim scientists, like Abū al-Rayhān al-Bīrūnī and Avicenna, questioned some of these old ideas.

In the 1500s, Georg Agricola wrote about how to get metals from rocks, which helped others learn more about materials.

During the time when science began to change, scientists like Robert Boyle started to turn old ideas into real science. They tested things carefully. Later, scientists found out that air is made of many gases. Joseph Black found one called ‘fixed air’, which we now know as carbon dioxide. Others found hydrogen and oxygen.

In the 1800s, John Dalton said that everything is made of tiny parts called atoms. Scientists also learned how atoms stick together and discovered how to sort all the known elements into the periodic table.

By the early 1900s, scientists learned about the inside of atoms. They found tiny parts like the electron and began to understand how atoms work together.

Practice

In the practice of chemistry, pure chemistry explores the basic ideas and rules of chemistry, while applied chemistry uses this knowledge to create new technologies and solve problems in the real world.

Chemistry is usually split into several main areas. These include:

• Analytical chemistry, which studies how to analyze materials to understand what they are made of and their structure.
• Biochemistry, which looks at the chemicals and reactions in living organisms.
• Inorganic chemistry, which focuses on compounds made from metals and other elements.
• Materials chemistry, which deals with creating and understanding solid materials with special uses.
• Organic chemistry, which studies compounds based on carbon and their reactions.
• Physical chemistry, which examines the physical principles behind chemical systems and processes.
• Theoretical chemistry, which uses math and physics to explain chemical behavior.

There are also many other areas where chemistry connects with different fields, such as agrochemistry, astrochemistry, and environmental chemistry.

The chemical industry is a big part of the global economy, with major companies making and selling many useful products.