Paper2部分重要IGCSE化学考点梳理

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IGCSE化学考点 IGCSE化学

我们在准备IGCSE化学考试过程中，知识点的掌握是基础，也是最重要的一部分。为了帮助同学们做好化学复习工作，易伯华小编就为大家整理了Paper2部分的一些重要的IGCSE化学考点，知识点还不够扎实的同学们可以借此机会做好查漏补缺的工作。

这些是考试重点内容：

atomic structure

reactivity of metals

chemical test

organic

acid base and salt

calculation

energy change

bond energy

chromatography

elements,compounds and mixtures

the periodic table

rate of reaction

electrolysis

redox

equilibrium

gas in atmosphere

group 7

state of matter

group 1

titration

dot and cross digram

bonding and structure

crude oil

ammonia

formula equation

group 2

alkene

今天，我主要来说说chemical test部分。按照大纲要求：

（1）describe tests for these gases:

•hydrogen【‘pops’with a lighted splint】

•oxygen【relights a glowing splint】

•carbon dioxide【gives a white ppt.with limewater】

•ammonia【turns damp red litmus paper blue】

•chlorine【bleaches damp litmus paper】

（2）describe how to carry out a flame test

【1.The technique is first of all to clean the end of a piece of platinum or nichrome wire by dipping it into clean hydrochloric acid and then placing it in a roaring Bunsen flame.This procedure should be repeated until the wire no longer produces a colour in the flame.

2.The end of the wire should then be dipped into fresh hydrochloric acid and then into the solid sample under test.

3.The end of the wire should then be placed into a non-roaring,non-luminous Bunsen flame.】

（3）know the colours formed in flame tests for these cations:

•Li+is red

•Na+is yellow

•K+is lilac

•Ca2+is orange-red

•Cu2+is blue-green

（4）test of cations

•NH4+using sodium hydroxide solution and identifying the gas evolved【放出的气体是NH3】

•Cu2+,Fe2+and Fe3+using sodium hydroxide solution【Cu(OH)2,Fe(OH)2,Fe(OH)3颜色分别是blue,green,red-brown】

（5）test of anions

•Cl–,Br–and I–using acidified silver nitrate solution【AgCl,AgBr,AgI颜色分别是white,cream,yellow】

•SO42–using acidified barium chloride solution【BaSO4是white precipitate】

•CO32–using hydrochloric acid and identifying the gas evolved.【CO2 is released】

来，我们看道真题：

解析：b题，含有SO42-离子的检验，那使用含有Ba2+离子的物质检验，答案选择【solution of barium chloride】,观察到白色沉淀BaSO4,因此答案是【white precipitate】。

C问，flame test中是lilac颜色的metal ion是K，答案选择potassium.

怎么样，对于这部分的IGCSE化学考点你是不是已经深刻的掌握了呢？如果在学习过程中还有什么疑问，欢迎随时咨询我们的在线老师，让老师一对一为你进行专业的课程学习辅导吧！