Chemistry
From RationalWiki
| It works! |
| Major disciplines |
| Science articles |
| Philosophy of science |
Chemistry is the branch of science that studies the interaction between atoms, and how atoms form molecules and compounds. The science mostly concerns itself with the activities of the outer electrons of atoms and provides the basic rules on which biological sciences are based. Essentially, if someone marvels at how amazing it is that a protein folds together, or that coal and oil happens to burn to create energy, it is the rules governed by chemistry that make it happen.
Contents |
[edit] Main disciplines
- Organic chemistry - the study of molecules containing carbon (smells bad).
- Inorganic chemistry - the study of molecules not containing carbon (doesn't necessarily smell good).
- Physical chemistry - the study of interatomic or intermolecular physics, such as thermodynamics, kinetics, and quantum chemistry (doesn't smell much at all).
- Biochemistry - the study of chemical reactions in living things.
- Analytical chemistry - specifically looking at and identifying chemicals. As atoms and molecules are too small to see, this is often quite demanding.
- Pharmaceutical chemistry - combination of organic, metalo-organic, inorganic and analytical chemistry to produce and study end-effects of pharmaceuticals.
[edit] Other sub-disciplines
- Green chemistry - seeks to produce environmentally friendly chemicals and chemical processes.
- Photochemistry - studies the interactions of chemicals with light, which often produces dramatically different results than merely heating the chemicals.
- Computational chemistry - uses computers and complex quantum physics, thermodynamic or kinetic calculations to predict the behavior of atoms and molecules without requiring a "wet" chemistry experiment.
[edit] How far and how fast
- Thermodynamics - best described as the energy of an atom or molecule. Thermodynamic driving forces cause certain products to be favored over others in reactions. The lowest energy, and therefore most stable product, is the one eventually produced.
- Kinetics - governs the speed of a reaction. The most stable product may not be the one produced because it is produced slowly. For example, graphite is much more stable than diamond, but diamonds still exist because their rate of decay to graphite is minutely small.
[edit] Benefits
Modern chemistry is capable of amazing things, both analyzing the exact structure of complex molecules and synthesizing naturally-occurring and "invented" molecules and substances. From dyes to plastics, to the processes that purify the silicon used in computer chips, the science of chemistry is inextricably linked with how the human race is able to live today.
[edit] Chemical bonding
Most atoms bond with each other by sharing electrons between their valence shells in what is known as a covalent bond. It is the breaking and making of such bonds that governs most, if not all of chemistry. When more than one atom is bonded together, the result is called a molecule, ranging from the small, such as methane, to the very large such as DNA.
Ionic bonding is the special case whereby an electron is formally transferred from one atom to another, forming ions. As an atom has an overall neutral charge, the removal of an electron leaves a positively charged ion and the addition of an electron leaves a negatively charged ion. Electrostatic forces then attract the positively charged ions to the negatively charged ions. An example of ionic bonding is in common salt, sodium chloride, which contains an equal number of positively charged sodium ions and negatively charged chloride ions bonded electrostatically.