- Chemistry | Definition, Topics, Types, History, Facts | Britannica
The identification of pure substances and the analysis of chemical mixtures enable all other chemical disciplines to flourish The importance of analytical chemistry has never been greater than it is today
- Chemical compound | Definition, Examples, Types | Britannica
In fact, there are millions of chemical compounds known, and many more millions are possible but have not yet been discovered or synthesized Most substances found in nature—such as wood, soil, and rocks—are mixtures of chemical compounds
- Chemical reaction | Definition, Equations, Examples, Types - Britannica
Chemical reactions differ from physical changes, which include changes of state, such as ice melting to water and water evaporating to vapor If a physical change occurs, the physical properties of a substance will change, but its chemical identity will remain the same
- Chemical element | Definition, Origins, Distribution, Facts | Britannica
A chemical element is any substance that cannot be decomposed into simpler substances by ordinary chemical processes Elements are the fundamental materials of which all matter is composed Learn more about the origins, distribution, and characteristics of chemical elements in this article
- Chemical formula | Definition, Types, Examples, Facts | Britannica
Chemical formula, any of several kinds of expressions of the composition or structure of chemical compounds The forms commonly encountered are empirical, molecular, structural, and projection formulas
- Adrenochrome | Description, Properties, History, Popular Culture . . .
Adrenochrome, unstable chemical compound formed by the oxidation of epinephrine (also known as adrenaline) and having the chemical formula C9H9NO3 Its name is a combination of the words adrenaline, referring to its source, and chrome, referring to its having a colour (violet)
- chemical energy - Kids | Britannica Kids | Homework Help
Chemical energy is a form of potential energy that is in all substances Food is the most important source of chemical energy for living things The chemical energy in food is converted, or changed, by the body into moving mechanical energy and heat energy
- Natural gas - Composition, Properties, Uses | Britannica
Natural gas - Composition, Properties, Uses: Natural gas is a hydrocarbon mixture consisting primarily of saturated light paraffins such as methane and ethane, both of which are gaseous under atmospheric conditions The mixture also may contain other hydrocarbons, such as propane, butane, pentane, and hexane In natural gas reservoirs even the heavier hydrocarbons occur for the most part in
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