1、教學內(nèi)容分析:
本節(jié)內(nèi)容選自江蘇教育出版社教材普通高中課程標準實驗教科書化學(1)必修專題三第二單元第二部分。重點介紹了鐵的化學性質(zhì)。從學生已有的金屬及其化合物的舊知識遷移出鐵、銅可能具有的化學性質(zhì)。二價鐵和三價鐵的相互轉(zhuǎn)化是本節(jié)課的難點,關(guān)于鐵化合物和亞鐵化合物的相互轉(zhuǎn)化的教學,啟發(fā)學生運用氧化還原的觀點理解轉(zhuǎn)化的實質(zhì),用離子方程式表示反應(yīng)過程。增加二價鐵離子與三價鐵離子相互轉(zhuǎn)化的實驗方案設(shè)計,并組織學生對設(shè)計的方案進行評價,培養(yǎng)學生的創(chuàng)新意識。三價鐵離子的檢驗可采取邊講邊實驗的方法,要求學生在觀察、分析實驗后,總結(jié)鐵的化合物和亞鐵化合物相互轉(zhuǎn)換的知識分析和解釋,以求學會運用所學知識解決實際問題。
本單元的知識體系打破了以往元素化合物知識學習中的“結(jié)構(gòu)-性質(zhì)-制備-用途”的傳統(tǒng)模式,而是從人們熟悉的這些元素及其化合物在生產(chǎn)生活中懂得應(yīng)用事例著手,引發(fā)學生思考,進而產(chǎn)生探究的欲望。本節(jié)課主要研究的是鐵、銅及其化合物的性質(zhì),根據(jù)新課程內(nèi)容特點、學習目標的確定、學習者情況的分析可叢三方面著手:
(1)引導學生從生活常識發(fā)現(xiàn)兩者性質(zhì)上的差異。
(2)從學生已有的金屬及其化合物的舊知識遷移出鐵、銅可能具有的化學性質(zhì)。
(3)把實驗主動權(quán)交給學生,通過推測、設(shè)計探究實驗以及學生自主實驗探究認識Fe2+與Fe3+的區(qū)別和轉(zhuǎn)化。從而強化學生自主參與實驗探究的意識。激發(fā)學生學習化學、思考化學的積極性,促使學生學習方法的改變。
(4)最后由學生總結(jié)歸納三方面的結(jié)論要點,嘗試用簡潔的圖示方法自主構(gòu)建“鐵三角”關(guān)系。
4.比較等級的特殊用法:
、.有些詞的比較級和最高級有兩種不同形式, 意義上也有所不同, 如: older / oldest(比較老/最老的), elder / eldest (年齡比較大的/最大的); farther / farthest用于本義, 表示“比較遠的/最遠的”, 而further / furthest常用于引申意義, 表示“更進一步的,更深一層的/最深層的”
a. He is the oldest comrade in our office.
b. He is the eldest son in the family.
c. He went abroad for further studies.
②.表示“比…多(大)幾倍”時, 用“倍數(shù)+ as…as” 結(jié)構(gòu)或“倍數(shù)+比較級+than…”表示
a. This book costs twice as much as that one.
b. The university is three times as big as it was in 1980. =The university is three times bigger than it was in 1980.
③.可用much, far, still, even等修飾比較級, 表示 “更…”, “…得多”之意
a. Her handwriting is much better than mine.
b. This street is far wider and longer than any other street in Beijing.
④.可用“名詞詞組或數(shù)詞詞組+比較級”的結(jié)構(gòu)來表示“比…相差多少”, 如: a head taller, ten minutes later, two meters longer, a few steps further
⑤.比較級+ and +比較級表示“越來越…”的意思
a. Summer is coming. It is getting hotter and hotter.
、. “the +比較級+主語+謂語+其他, the +比較級+主語+謂語+其他” 表示 “越… , 就越…”
a. The harder you study, the more knowledge you will get.
b. The more you work for other people, the happier you will feel.
、.more…than…有時表示“與其說…, 倒不如說…”
a.. He is more diligent than wise.與其說他聰明,不如說他勤奮
b. He is more a friend than a teacher.與其說他是一位老師,不如說更像一位朋友
、.“no+比較級+than…”和“not +比較級+than…”所表示的意思不相同, 前者表示“和…一樣不…”(即兩者都不…), 后者表示“不比…更… ”(僅否定前者, 即表示前者不如后者)
a. His English is no better than mine. (兩人的英語都不好)
b. His English is not better than mine. 他的英語不如我的英語好(僅否定 “他的英語”)
c. He is no taller than I.他和我一樣不高./ He is not taller than I.他不如我高.
、.有時用比較級表示最高級的意思, 如:
a. It can’t be safer.再安全不過了.
b. She can’t be more beautiful. 她簡直美極了
c. He works harder than the other students in his class.
d. He works harder than any other student in his class.
⑩. “the +序數(shù)詞+最高級” 表示“第幾”之意
a. China is the third largest country in the world.
b. The Yellow River is the second longest river in China.
3.最高級的用法: 三方或三方以上進行比較時, 用最高級, 最高級前多用the, 基本形式為: the + adj / adv的最高級 + (名詞) + 表示范圍的短語或從句
a. He is the eldest among the sisters.
b. Shanghai is the biggest centre of industry in China.
c. Beijing is one of the most beautiful cities in China.
2.比較級的用法: 兩方進行比較時, 多用than
a. It is colder today than it was yesterday.
b. His handwriting is more beautiful than yours.
c. He did his homework more carefully than you did yours.
1.比較級和最高級的形式:
①.規(guī)則變化:
a.在單音節(jié)形容詞后及少數(shù)以-er, -ow, -ble, -ple結(jié)尾的雙音節(jié)形容詞和少數(shù)副詞原級后, 加-er, -est或-r, -st, 如: strong, young, clever, able, simple, narrow, hard, fast, slow等
b.在以-e結(jié)尾的單音節(jié)形容詞和少數(shù)副詞原級后, 加-r, -st, 如: brave, wide等
c.形容詞以發(fā)短元音的元音字母+輔音字母結(jié)尾時, 雙寫輔音字母, 再加-er, -est,如: big, hot, thin等
d.輔音字母+y結(jié)尾的單音節(jié)及雙音節(jié)形容詞和少數(shù)副詞(由形容詞+ly構(gòu)成的副詞除外), 要將y變?yōu)閕, 再加-er, -est, 如: easy, happy, early等
e.在雙音節(jié)和多音節(jié)形容詞和大多數(shù)副詞原級前可以加more, most表示比較級和最高級, 如: useful, childish, important, happily, clearly, quickly等
f.有少數(shù)單音節(jié)形容詞加more / most構(gòu)成比較級和最高級, 如: fond, tired, pleased, glad, often, fit等
g.下列形容詞和副詞的比較級和最高級可用兩種方法構(gòu)成: cruel, strict, friendly, often, fit
②.不規(guī)則變化的形容詞如: good / well, many / much, bad / badly, little, far
2.原級的用法:
①.表示被比較雙方在某一方面相等或相同時, 用as + adj / adv + as結(jié)構(gòu), 表示“…和…一樣”
a. Xiao Li is as tall as his sister.
b. It is as cold today as it was yesterday.
c. There are as many seats in this hall as in that hall.
、.表示被比較雙方在某一方面不相等或不同時, 用not as / so + adj / adv + as, 表示“…和…不一樣”
a. Xiao Li is not as / so tall as his brother.
b. It is not so / as cold today as yesterday.
c. There are not so / as many seats in this hall as in that hall.
1.原級的形式: 即原形
7.作狀語時,各類副詞的排列順序一般為: 方式副詞, 地點副詞, 時間副詞
a. He behaved well here yesterday.
形容詞和副詞的比較等級
6.修飾全句的副詞通常放在句首
a. Truly he is an honest man.
b. Still, in spite of what you say, I don’t think it is true.
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