2025年2月15日 · chemistry, the science that deals with the properties, composition, and structure of substances (defined as elements and compounds), the transformations they undergo, and the energy that is released or absorbed during these processes.

2025年2月12日 · The term biochemistry is synonymous with two somewhat older terms: physiological chemistry and biological chemistry. Those aspects of biochemistry that deal with the chemistry and function of very large molecules (e.g., proteins and nucleic acids) are often grouped under the term molecular biology. Biochemistry has been known under that term ...

Chemical kinetics, the branch of physical chemistry that is concerned with understanding how fast or how slow chemical reactions occur (that is, their rates). The principles of chemical kinetics apply to purely physical processes as well as to chemical reactions.

2025年2月14日 · Salt, also called sodium chloride, mineral substance of great importance to human and animal health, as well as to industry. The mineral form halite, or rock salt, is sometimes called common salt to distinguish it from a class of chemical compounds called salts. Learn more about salt in this article.

2025年1月31日 · Oxidation-reduction reaction - Redox, Origins, Chemistry: Of the chemical processes now regarded as redox reactions, combustion was the earliest focus of philosophical and scientific attention. The Greek scientific philosopher Empedocles listed fire as one of the four elements of matter.

2025年1月3日 · Changes in seawater chemistry. The acidity of any solution is determined by the relative concentration of hydrogen ions (H +). A larger concentration of H + ions in a solution corresponds to higher acidity, which is measured as a lower pH.

2025年2月12日 · He developed the modern system of naming chemical substances and has been called the “father of modern chemistry” for his emphasis on careful experimentation. How was Antoine Lavoisier educated? After studying the humanities and sciences at the Collège Mazarin, Antoine Lavoisier studied law.

2025年2月13日 · Caffeine has a stimulating effect on the central nervous system, heart, blood vessels, and kidneys.It also acts as a mild diuretic.Caffeine’s potent stimulatory action makes it a valuable antidote to respiratory depression induced by drug overdose (e.g., from morphine or barbiturates). The positive effects that have been described in people who use caffeine include …

2025年1月22日 · catalysis, in chemistry, the modification of the rate of a chemical reaction, usually an acceleration, by addition of a substance not consumed during the reaction. The rates of chemical reactions—that is, the velocities at which they occur—depend upon a number of factors, including the chemical nature of the reacting species and the ...

Coordination compound - History, Chemistry, Nomenclature: Perhaps the earliest known coordination compound is the bright red alizarin dye first used in India and known to the ancient Persians and Egyptians. It is a calcium aluminum chelate complex of hydroxyanthraquinone.