It may be tempting to equate the concept of venom with poison, but to do so would be inaccurate. Many plants, for example, are poisonous but present no harm to humans because they have learned not to eat them.
If a person knows nothing else about chemistry, he or she will likely know that water is H2O. The chemical formula for water is common knowledge, used in advertisements, elementary school science classes, and casual conversation.
Water pollution occurs when undesirable foreign substances are introduced into natural water. The substances may be chemical or biological in nature.
Next to a supply of air, nothing is so essential to life as a supply of high-quality water. We drink it, cook our food in it, use it as a source of energy, and lift a hundred pounds or so of it each time we stand up.
Xenon (its name derived from the Greek word xenos, meaning "strange"), is the heaviest of the noble gases. Discovered in 1898 in London by Sir William Ramsay and Morris Travers while engaged in their investigations of liquid air, xenon accounts for less than 1 ppm of the volume of Earth's atmosphere.
Ytterbium was discovered by the Swiss chemist Jean Charles Galissard de Marignac in 1878 and named after the town of Ytterby, in Sweden (the site of the discovery of the ore with which de Marignac worked). Its primary source is xenotime and monazite ores, which are mixtures of rare earth orthophosphates.
Carl Axel Arrhenius found in 1787 in a quarry near Ytterby, Sweden, a new mineral, which he named ytterbite, and made a summary analysis of it. Further, the Finnish chemist Johan Gadolin isolated in 1794 from this mineral an impure new oxide that he named ytterbia.
Zeolites are a large group of natural and synthetic hydrated aluminum silicates. They are characterized by complex three-dimensional structures with large, cagelike cavities that can accommodate sodium, calcium, or other cations (positively charged atoms or atomic clusters); water molecules; and even small organic molecules.
Like many transition metals, zinc has been known in impure form since ancient times. Brass (copper and zinc) coins were used by Egyptians and Palestinians as early as 1400 B.C.E.
Zirconium was discovered by the German chemist Martin H. Klaproth in 1789.
Zwitterions (the word is derived from the German for "hybrid ion") are ions that are electrically neutral overall but contain nonadjacent regions of positive and negative charges; they are sometimes referred to as "dipolar ions." The best-known examples of zwitterions are the free amino acids found in cells.
Jacobus Hendricus van't Hoff, born in Rotterdam, Netherlands, was in his youth, along with the French chemist Joseph Achille Le Bel, the cofounder of modern stereochemistry. He then became one of the fathers of modern physical chemistry.
Until the late 1700s static electricity was the only known form of electricity. Alessandro Volta, born in Como, Italy, is best known for discovering current electricity and for developing the voltaic pile, which became an invaluable tool in electrochemistry.
Selman Waksman changed the course of medical history while investigating how soil microbes defended themselves against invaders. He and coworkers isolated twenty-two new defensive compounds produced by soil microbes and in the process discovered streptomycin, the first antibiotic effective against tuberculosis.
The American biochemist James Dewey Watson was a discoverer of the double-helical structure of the deoxyribonucleic acid molecule.
One of the few who have achieved success in two disparate fields, chemist and statesman Chaim Weizmann was born on November 17, 1874, in the small town of Motol, Russia—part of what was known as the Pale of Settlement, an area where Jewish families were allowed to live. Beginning at age four he attended a religious school in which classes were conducted in Yiddish.
Alfred Werner, the founder of coordination chemistry, was born on December 12, 1866, in Mulhouse, Alsace, France (in 1870 annexed to Germany). He was the fourth and last child of Jean-Adam Werner, a foundry worker and locksmith, and his second wife, Salomé Jeanette Tesché, the dominant figure in the Werner household and a member of the wealthy Tesché family.
As a boy, Willstätter proved to be a gifted student and tried to attend the best schools in Germany. But since he was a Jew, he was denied admission and was forced to attend public school.
Friedrich Wöhler was born on July 31, 1800, at Eschersheim, near Frankfurt-am-Main, Hesse. The son of a veterinary surgeon, young Wöhler attended public schools in Frankfurt and passed exams qualifying him for admission to a university in 1820.
Robert Burns Woodward is generally recognized as the leading organic chemist of the twentieth century. He and his coworkers determined the structures of biologically active natural products, developed theoretical rules for predicting the outcomes of organic reactions, and synthesized some of the most complex molecules known to humans.
Rosalyn Sussman Yalow was awarded the Nobel Prize in physiology or medicine in 1977 for her pioneering work in developing the technique known as radioimmunoassay (RIA), a method first applied to the measurement of concentrations in blood of the hormone insulin. Subsequently the use of RIA was extended to include the detection and quantification of a wide range of substances of biological interest, including other hormones, serum proteins, enzymes, viruses, and tumor antigens.
Hideki Ogawa (he changed his surname upon marrying Sumi Yukawa) was born on January 23, 1907, in Tokyo. A year thereafter his family moved to Kyoto, where he was raised and attended school.
Richard Zsigmondy received the 1925 Nobel Prize in chemistry for his elucidation of the nature of colloidal suspensions. With Henry Siedentopf (1872–1940), he invented, used, and promoted the ultramicroscope.