安裝中文字典英文字典辭典工具!
安裝中文字典英文字典辭典工具!
|
- Chemistry | Definition, Topics, Types, History, Facts | Britannica
Cooking, fermentation, glass making, and metallurgy are all chemical processes that date from the beginnings of civilization Today, vinyl, Teflon, liquid crystals, semiconductors, and superconductors represent the fruits of chemical technology
- Chemical reaction | Definition, Equations, Examples, Types - Britannica
A chemical reaction is a process in which one or more substances, the reactants, are converted to one or more different substances, the products Substances are either chemical elements or compounds
- Chemical Definition Meaning | Britannica Dictionary
CHEMICAL meaning: 1 : of or relating to chemistry; 2 : working by means of chemicals
- Chemical compound | Definition, Examples, Types | Britannica
Chemical compound, any substance composed of identical molecules consisting of atoms of two or more chemical elements All the matter in the universe is composed of the atoms of more than 100 different chemical elements, which are found both in pure form and combined in chemical compounds
- 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
- chemical reaction - Students | Britannica Kids | Homework Help
Chemical reactions abound in the natural world, changing the composition of matter within Earth, on its surface, and in the atmosphere, and driving a vast array of processes in living systems Chemical reactions in the digestive system help break down food into glucose and other constituent molecules that can be absorbed by cells
- 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 People have invented ways to use the chemical energy of substances to power machines
|
|
|