2023年AP课程考试报名开启，AP报名费用多少？
2023年AP课程考试报名开启，9月19日-10月18日。尤其是社会考生！为了帮助大家更好的选择AP报考科目，我们帮大家总结了AP考试的考试趋势，5分率以及AP报名费用，希望能够对大家有帮助！ AP考试趋势： 2019年以前，...
Edexcel A Level Chemistry:复习笔记7.7.4 Thin-Layer Chromatography
Thin Layer Chromatography Principles of Chromatography Chromatography is a technique that enables the separation of mixtures and includes: thin-layer chromatography (TLC) column chromatograp...
Edexcel A Level Chemistry:复习笔记7.7.3 Proton NMR
Proton NMR - Introduction Nuclear Magnetic Resonance (NMR) spectroscopy is used for analysing organic compounds All samples are measured against a reference compound – Tetramethylsilane (TMS) Tetr...
Edexcel A Level Chemistry:复习笔记7.7.2 Carbon-13 NMR
Using Carbon-13 Data Nuclear Magnetic Resonance (NMR) spectroscopy is used for analysing organic compounds Atoms with odd mass numbers usually show signals on NMR For example, isotopes of at...
Edexcel A Level Chemistry:复习笔记7.7.1 Mass Spectrometry
Using Mass Spectra At AS level, you have used mass spectrometry to determine: Relative atomic mass from isotopic abundance Possible molecular formulae from molecular ion peaks Organic struct...
Edexcel A Level Chemistry:复习笔记7.6.6 Organic Techniques - Purity
Melting & Boiling Point Determination Melting point determination The melting point of a solid is indicative of its purity and identity A melting point can be matched to a known substanc...
Edexcel A Level Chemistry:复习笔记7.6.5 Organic Techniques - Purification
Purification Methods There are different methods to purify organic compounds, including: Solvent extraction / use of a separating funnel Use of drying agents Recrystallisation Solvent extrac...
Edexcel A Level Chemistry:复习笔记7.6.4 Organic Techniques - Preparation
Distillation & Refluxing Simple distillation Simple distillation is a common practical completed in organic chemistry It is used as there are times that a reaction does not go to complet...
Edexcel A Level Chemistry:复习笔记7.6.3 Increasing Chain Length
Grignard Reagents If we need to increase the chain length we can use Grignard reagents Preparing Grignard reagents A halogenoalkane is dissolved in dry ether and reacted with magnesium to p...
