2022 ISSCY联合国高中人文社科写作大赛报名开启！附获奖作文赏析
ISSCY 联合国协会写作比赛 是一项针对全球高中生的研究型写作学术活动，为了促进世界各地中学生对人文和社会科学的研究，ISSCY邀请年轻思想者将他们的研究论文提交评审委员会审议。 学生将提交初赛建议，如果被选...
AQA A Level Chemistry复习笔记3.4.3 Reactions of Alkenes
Alkenes: Reactions Alkenes are very useful compounds as they can undergo many types of reactions They can therefore be used as starting molecules when making new compounds Electrophilic addi...
AQA A Level Chemistry复习笔记3.4.2 Isomerism in Alkenes
Isomerism in Alkenes Unsaturated compounds In unsaturated compounds, the groups attached to the C=C carbons remain fixed in their position This is because free rotation of the bonds about th...
AQA A Level Chemistry复习笔记3.3.3 Ozone Depletion
Uses Fluorohalogenoalkanes The most common halogenoalkanes are chlorofluorocarbons (CFCs) These compounds contain carbon atoms with chlorine and fluorine atoms attached to them E.g. CCl3F an...
AQA A Level Chemistry复习笔记3.3.2 Reactions of Halogenoalkanes
The Key Reactions of the Halogenoalkanes Types of Reactions that halogenoalkanes undergo: Halogenoalkanes are much more reactive than alkanes due to the presence of the electronegative halog...
AQA A Level Chemistry复习笔记3.2.4 Chlorination of Alkanes
Free Radical Substitution Free-radical substitution of alkanes Alkanes can undergo free-radical substitution in which a hydrogen atom gets substituted by a halogen (chlorine/bromine) Since ...
AQA A Level Chemistry复习笔记3.2.3 Combustion of Alkanes
Combustion Alkanes are combusted (burnt) on a large scale for their use as fuels Complete combustion When alkanes are burnt in excess (plenty of) oxygen, complete combustion will take place ...
AQA A Level Chemistry复习笔记3.2.2 Modification of Alkanes by Cracking
Cracking Alkanes are hydrocarbons that can be produced by the addition reaction of hydrogen to an alkene or by cracking of longer alkane chains Crude oil Crude oil is a mixture of hydrocarbo...
AQA A Level Chemistry复习笔记3.1.5 Stereoisomerism
Stereoisomerism: Geometrical Isomerism Stereoisomers are compounds that have the same atoms connected to each other, however the atoms are differently arranged in space There are two types o...
AQA A Level Chemistry复习笔记3.1.4 Structural Isomerism
Molecules: Straight, Branched & Cyclic Straight, branched and cyclic organic molecules are also called aliphatic compounds as long as they do not contain a benzene ring Straight-chain St...
AQA A Level Chemistry复习笔记3.1.3 Nomenclature
Nomenclature Systematic nomenclature can be used to name organic compounds and therefore make it easier to refer to them The alkanes provide the basis of the naming system and the stem of ea...
AQA A Level Chemistry复习笔记3.1.2 Types of Formulae
Types of Formulae The general formula is a formula that represents a homologous series of compounds using letters and numbers Eg. the general formula of alkanes is CnH2n+2 A homologous serie...
