最后一周！2022年纽约时报夏季读写比赛即将结束，速度报名！
2022《纽约时报》夏季读写比赛 报名即将截止！ 学术活动时间：2022年6月10日-8月19日 2022纽约时报夏季读写比赛 自2010年起， 《纽约时报》每年夏天都会举办的夏季读写比赛，目前全球已有超过8万名中学生参与...
CIE A Level Chemistry复习笔记3.4.1 Production of Alcohols
Production of Alcohols Alcohols are compounds that contain at least one hydroxy (-OH) group The general formula of alcohols is CnH2n+1OH Alcohols can be prepared by a wide range of chemical reactio...
CIE A Level Chemistry复习笔记3.3.5 Reactivity of Halogenoalkanes
Reactivity of Halogenoalkanes The halogenoalkanes have different rates of substitution reactions Since substitution reactions involve breaking the carbon-halogen bond the bond energies can be used ...
CIE A Level Chemistry复习笔记3.3.4 SN1 & SN2
Halogenoalkanes: SN1 & SN2 Mechanisms In nucleophilic substitution reactions involving halogenoalkanes, the halogen atom is replaced by a nucleophile These reactions can occur in two different ...
CIE A Level Chemistry复习笔记3.3.3 Elimination Reactions of Halogenoalkanes
Halogenoalkanes: Elimination Reactions In an elimination reaction, an organic molecule loses a small molecule In the case of halogenoalkanes this small molecule is a hydrogen halide (eg. HCl) The h...
CIE A Level Chemistry复习笔记3.3.2 Substitution Reactions of Halogenoalkanes
Nucleophilic Substitution Reactions of Halogenoalkanes Halogenoalkanes are much more reactive than alkanes due to the presence of the electronegative halogens The halogen-carbon bond is polar causi...
CIE A Level Chemistry复习笔记3.3.1 Production of Halogenoalkanes
Production of Halogenoalkanes: Substitution & Addition Reactions Halogenoalkanes are alkanes that have one or more halogens They can be produced from: Free-radical substitution of alkanes Elect...
CIE A Level Chemistry复习笔记3.2.11 Markovnikov's Rule
Alkenes: Stability of Cations & Markovnikov's Rule Carbocations are positively charged carbon atoms with only three covalent bonds instead of four There are three types of carbocations: primary...
CIE A Level Chemistry复习笔记3.2.10 Electrophilic Addition of Alkenes
Alkenes: Electrophilic Addition The double bond in alkenes is an area of high electron density (there are four electrons found in this double bond) This makes the double bond susceptible to attack ...
2022剑桥TMUA数学考试介绍，哪些学校和专业需要TMUA？
TMUA这两年突然“异军突起”，先是2021年剑桥宣布所有申请计算机科学的学生都要考 TMUA；再是今年剑桥砍掉 ECAA，改为 TMUA。可以说 TMUA 是这两年剑桥最重视的考试了！连LSE 都官网鼓励申请学生考TMUA。为什么TMUA...
CIE A Level Chemistry复习笔记3.2.9 Test for Unsaturation
Test for Unsaturation Halogens can be used to test if a molecule is unsaturated (i.e. contains a double bond) Br2(aq) is an orange or yellow solution, called bromine water and this is the halogen m...
CIE A Level Chemistry复习笔记3.2.8 Reactions of Alkenes
Reactions of Alkenes 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 addition ...
