IGCSE化學paper2重要考點

考試倒計時僅剩3天考前焦慮？

不必驚慌！

該會的你都會了！

6月12號paper 2會考哪些內容呢？我這里提供下考試的重點topic，沒復習好的可要抓緊時間了。

來，上點干貨，這些是考試重點內容：

atomic structurereactivity 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，我主要來說說chemical test部分。

按照大綱要求：

（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?【放出的氣體是NH3】

? Cu2+, Fe2+ and Fe3+ using sodium hydroxide solution 【Cu(OH)2, Fe(OH)2, Fe(OH)3顏色分別是blue, green, red-brown】

（5）test of anions??Cl–, Br–?and I–?using acidified silver nitrate solution?【AgCl, AgBr, AgI顏色分別是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】

來，我們看道真題：
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