Fractional Distillation Crude oil is currently the world's main source of organic chemicals As a mixture, it isn’t a very useful substance, but the different hydrocarbons that make up the mixture, ...
Organic Definitions & Terminology Organic chemistry is the chemistry of carbon compounds Carbon forms a vast number of compounds because it can form strong covalent bonds with itself This enabl...
Group 7: Physical Properties The group 7 elements are called halogens The halogens have uses in water purification and as bleaching agents (chlorine), as flame-retardants and fire extinguish...
Group 2: Trends Chemical trends All elements in Group 2 (also called alkali earth metals) have two electrons in their outermost principal quantum shell All Group 2 metals can form ionic compounds i...
The Periodic Table: Structure & Classification The periodic table is a list of all known elements arranged in order of increasing atomic number, from 1 to 118. In addition to this, the elements...
Oxidation & Reduction There are three definitions of oxidation and reduction used in different branches of chemistry Oxidation and reduction can be used to describe any of the following proces...
Reversible Reactions & Dynamic Equilibrium Reversible reaction Some reactions go to completion where the reactants are used up to form the products and the reaction stops when all of the reacta...
Collision Theory Collision theory The collision theory states that for a chemical reaction to take place the particles need to collide with each other in the correct orientation and with enough ene...
英国教育可以分两个系统：公立教育和私立教育。这两种教育主要区别在于， 公立教育系统里学校的财政开支和管理由中央政府或者当地政府进行管控。大部分公立学校为走读学校， 全英共有39所公立寄宿制学校， 但这些...
