第一篇：八年級(jí)(下)科學(xué)第二章重點(diǎn)知識(shí)聽寫

八年級(jí)（下）科學(xué)第二章重點(diǎn)知識(shí)聽寫

1、空氣中的主要成分和體積比：

①________（_______）；②________（_______）；③________（_______）；④其它??（0.06%）

2、在測(cè)定空氣中氧氣含量的實(shí)驗(yàn)中，我們點(diǎn)燃________內(nèi)的紅磷，觀察到現(xiàn)象是______________________； 火焰熄滅后，振蕩集氣瓶，打開導(dǎo)管上的夾子，出現(xiàn)的現(xiàn)象是________________________，集氣瓶?jī)?nèi)水位變_________，大約上升為瓶子總體積的_________；消耗的氣體跟剩下的氣體的體積比為____________。原因是_______________________________。此實(shí)驗(yàn)除了用紅磷還可以用其它物質(zhì)代替，如____________。

3、寫出空氣中的各成分的作用：（舉一例）

氧氣_____________；氮?dú)鈅____________；二氧化碳________________；稀有氣體_______________

4、寫出硫和氧氣反應(yīng)的現(xiàn)象及化學(xué)方程式：

______________________________________________________、____________________________________

5、寫出鐵和氧氣反應(yīng)的現(xiàn)象及化學(xué)方程式：

______________________________________________________、____________________________________

6、呼吸作用的反應(yīng)過(guò)程可表示為（文字）：_____________________________________________。

7、緩慢氧化舉例：__________________、__________________；快速氧化舉例：__________________。

8、可燃物燃燒的兩個(gè)條件：__________________、__________________。

9、實(shí)驗(yàn)室制取氧氣的三個(gè)化學(xué)方程式：

（1）_____________________________________（固—固反應(yīng)）（2）_____________________________________（固—固反應(yīng)）

（3）______________________________________（固—液反應(yīng)）上述三個(gè)反應(yīng)的類型都是_________反應(yīng)。

10、實(shí)驗(yàn)室制取氧氣時(shí)，裝置中儀器名稱：（7個(gè)）

（1）__________、（2）_________、（3）_________、（4）___________、（5）___________、（6）___________、（7）___________、11、實(shí)驗(yàn)時(shí)的注意點(diǎn)：（7個(gè)）

（1）酒精燈使用外焰是因?yàn)椋篲________________________________（2）試管口略向下傾斜是因?yàn)椋篲________________________________（3）導(dǎo)管不能伸入試管太長(zhǎng)是因?yàn)椋篲________________________________（4）實(shí)驗(yàn)開始前要等到集氣瓶中的氣泡連續(xù)不斷放出才能收集是因?yàn)椋篲___________________________（5）試管口要塞一團(tuán)棉花是因?yàn)椋篲________________________________（6）實(shí)驗(yàn)結(jié)束后，因先把導(dǎo)管從集氣瓶中取出，再熄滅酒精燈是因?yàn)椋篲_____________________________（7）用收集的一瓶氧氣做“鐵絲在氧氣中燃燒實(shí)驗(yàn)”時(shí)，在瓶子底一定要放一些____________________，是因?yàn)椋篲________________________________。

12、呼吸道組成：______________________________________________________________________。

13、吸氣和呼氣時(shí)依靠________和________的活動(dòng)而產(chǎn)生的。吸氣過(guò)程：_____肌收縮，_______變得扁平，_______收縮，_______舒張，________向上、向外移升，此時(shí)，____________增大，__________減少。

14、“植物制造淀粉的實(shí)驗(yàn)”（天竺葵實(shí)驗(yàn)）：

（1）暗處理的目的是______________________________；（2）水浴加熱的目的_______________________；（3）葉片放酒精中的目的__________________________；（4）碘液的作用_________________________；（5）本實(shí)驗(yàn)的結(jié)論_____________________________；（6）本實(shí)驗(yàn)需要的器材：________________________。

15、實(shí)驗(yàn)室制取二氧化碳：__________________________________________________。

16、檢驗(yàn)二氧化碳的方程式：__________________________________________________。

17、臭氧集中在大氣的__________層里，作用是______________________________________________。

18、PH低于__________的酸性降水稱為酸雨，形成的化學(xué)方程式: ______________________________。

19、空氣污染指數(shù)的項(xiàng)目：__________、__________、__________、_________________、__________。

第二篇：二年級(jí)下語(yǔ)文重點(diǎn)聽寫詞

二年級(jí)下語(yǔ)文重點(diǎn)聽寫詞

世界筍芽呼喚微笑泥濘芬芳應(yīng)該環(huán)繞隱約茂盛鳳凰雄偉輝煌哄騙彩虹蜘蛛價(jià)錢批評(píng)玻璃破碎繼續(xù)驕傲胳膊晃蕩樓梯腦筋討厭蛋殼欺負(fù)翅膀檢查斥責(zé)夸獎(jiǎng)傳染嚴(yán)寒 特別解凍追趕刨根問(wèn)底

第三篇：八年級(jí)下重點(diǎn)作文

AWeather report

Hello, everyone.I’ll tell you the weather.It will be cloudy, and there will be some showers during the daytime.The hightemperature is 20 degrees, and the low is 10 degrees.So it’s cold at night.Please wear warm clothes if you go out at night.Thank you for listening.Spring

Spring is coming.The snow is melting.The days get longer in spring.Weather is warming.Wind blows gently through the trees.The flowers blossom one by one.The trees turn green.Everything begins to grow in spring.I like spring best because I can do sportsnow.I can play outdoors.Ican play soccer.I can fly kites with my friends.Running is also interesting in spring.Do you like cycling?Then let’s go together.The plants are very important to us

As we all know, plants are important to our human beings, They have many uses.Firstly, I think, they are for food.We know we feed on rice, wheat, cornand vegetablesand so on, they are all plants.Secondly, they are for medicine, we make many medicines from plants, Thirdly, the are for clothing ,our clothes are often made of cotton, and cotton is a kind of plant ,Finally I thinkthey are for things we use to work, books, paper ,pencils are all from

plants.In a word, plants are very useful and important to us.A trip to the zoo

I went to the zoo with my parents last Sunday.The weather wassunny, so we wear sunglass to protect our eyes from the sun, There were all kinds of animals there.such as monkeys ,horses, zebras, giraffes and geese.I like the monkey best.because they are lovely and amazing, my mother likes the geese best, because theylookedlike snowballs,that day wewere tired, but we had a good time.Shall we keep animals in zoos?

Yesterday we had a discussion about if we should keep animals in zoos.Twenty students thought that it was good to keep animalsinzoosbecause people could see many different kinds of animals there and animals were taken good care of in zoos.Thirty students thought it was not good for animals.since the animals were kept in cages , they were not able to travel freely.Animals liked to live in nature.Planting trees

Last week the students of our school went to the hill to plant trees.We got up very early before the sun rose.We all wore old clothes.Assoon as we got there , we began to work.Some of us dug holes, and some carried trees and water.I dug a big hole and my

classmates Wang Mei took a small tree.She put the tree into the hole and then we put the earth in the hole.At last we watered the tree.We planted three hundred that day.When we came back , we were tired but very happy.請(qǐng)寫一篇關(guān)于河北的簡(jiǎn)單介紹，內(nèi)容包括以下要點(diǎn)：河北位于中國(guó)華北，首都北京周圍，臨近天津，省會(huì)城市是石家莊。占大地約19萬(wàn)平方公里；人口大約有6744萬(wàn)。主要的農(nóng)作物有小麥、玉米、谷子（broomcorn）等。河北有很多著名的景點(diǎn)，歡迎大家來(lái)河北旅游。

要求：內(nèi)容連貫，語(yǔ)句通順，60詞左右。

Hebei is in the north of China, around Beijing and next to Tianjin.Its capital city is Shijiazhuang.It covers about 190,000 square kilometers.Its main crops are wheat, corn broomcorn and so on.There are many famous places of interest in Hebei.Welcome to Hebei.Sunday ,April13th

Today is Sunday ,Istayed at home.Li Yang and I did the experiment that the teacher told us in class.We put a candle, a glass

and a dish on the desk.We filled the dish half on the desk.We put the candle on the dish ,and then lit it.After the candle burned for a few minutes, we put the glass over the candle , After a while the candlestopped burning, and the water inside the glass rose, How interesting science is!

Make a plan for summer holiday

Summering holiday is coming.I’m going to read English during the holidays every morning, thenI’ll do morning exercises every day.In the afternoon I’ll swim or go fishing.I like reading, so I’d like to spend some time in reading books.I’ll help my parents do some housework.In the evening, I’ll watch TV for one hour.What should we do to protect the Environment

We have only one earth.It’s our duty to protecttheenvironment.Ithink we should keep our schools clean and tidy.Don’t throw the rubbisheverywhere.And we should plant trees and flowersaround the cities.It’s important to recycle paper and water.Remeber to turn off when we finish washing hands.Don’t forgetto turn off the lights when we leave the room.We had better walk or rides bikes to school to keep our streets clean.We must do our best to make our world more and more beautiful in the future.

第四篇：八年級(jí)上冊(cè)重點(diǎn)知識(shí)

Unit 2 How often do you exercise?

help with housework幫助做家務(wù)on weekends在周末how often多久一次hardly ever幾乎從不

once a week每周一次twice a month每月兩次every day每天be free有空

go to the movies去看電影use the Internet用互聯(lián)網(wǎng)swing dance搖擺舞play tennis打網(wǎng)球

stay up late熬夜；睡得很晚at least至少have dance and piano lessons上舞蹈課和鋼琴課

go to bed early早點(diǎn)睡覺play sports進(jìn)行體育活動(dòng)be good for對(duì)……有好處go camping去野營(yíng)

not…at all一點(diǎn)兒也不……in one’s free time在某人的業(yè)余時(shí)間the most popular最受歡迎的such as比如；諸如old habits die hard積習(xí)難改go to the dentist去看牙醫(yī)

morn than多于；超過(guò)less than少于

help sb.with sth.幫助某人做某事How about…?......怎么樣？/ ……好不好？

want sb.to do sth.想讓某人做某事How many+可數(shù)名詞復(fù)數(shù)+一般疑問(wèn)句？……有多少……?

主語(yǔ)+find+that從句.……發(fā)現(xiàn)……spend time with sb.和某人一起度過(guò)時(shí)光

It’s+ adj.+ to do sth.做某事的……的。ask sb.about sth.向某人詢問(wèn)某事 by doing sth.通過(guò)做某事What’s your favorite……?你最喜愛的……是什么？

the best way to do sth.做某事的最好方式

第五篇：八年級(jí)下科學(xué)第二章課堂練習(xí)

八年級(jí)下科學(xué)課堂練習(xí)姓名

一、填空題

21、化學(xué)用語(yǔ)是一種特定的化學(xué)語(yǔ)言，它表示一定的化學(xué)含義，粒子符號(hào)周圍小數(shù)字也表示

著不同的意義。判斷下列化學(xué)符號(hào)①2NO、②Mg、③MgO中數(shù)字“2”所表示的意義，將其序號(hào)填2++

2在⑴⑵⑶的橫線上，以此為例，完成⑷⑸并舉例說(shuō)明不同化學(xué)符號(hào)中數(shù)字“2”的意義。⑴

表示元素的化合價(jià)的是；⑵ 表示分子個(gè)數(shù)的是；⑶ 表示

1個(gè)離子所帶電荷數(shù)的是；

⑷，；

⑸。

22．如圖所示為元素周期表的一部分，已知D元素的原子核內(nèi)有16個(gè)質(zhì)子，請(qǐng)回答下列問(wèn)

題：

（1）D元素屬于（填金屬、非金屬）元素。

（2）C元素的原子核內(nèi)有個(gè)質(zhì)子 A B（3）請(qǐng)推測(cè)有關(guān)B元素組成的單質(zhì)的兩點(diǎn)信息：

； C D E。

23．寫出下列物質(zhì)的化學(xué)式

硫酸鋁碳酸鈣氫氧化鎂，硝酸鉀五氧化二磷四氧化三鐵。

24．有下列這些物質(zhì)：①氧氣、②鐵、③一氧化碳、④氬氣、⑤水、⑥空氣、⑦食鹽、⑧澄清

石灰水、⑨硫粉。

屬于混合物的是；屬于單質(zhì)的是；屬于化合物的是；屬于氧化物的是

25．某種牙膏中含有抗牙腐蝕藥物，它的化學(xué)式為Na2FPO3。已知F在化合物中的化合價(jià)為

–1價(jià)，鈉的相對(duì)原子質(zhì)量是23，氧的相對(duì)原子質(zhì)量是16，磷的相對(duì)原子質(zhì)量是31。則

Na2FPO3由種元素組成，屬于（填“單質(zhì)”或“化合物”），其中磷的化合價(jià)為價(jià)，Na2FPO3的相對(duì)分子質(zhì)量是144，則氟的相對(duì)原子質(zhì)量

為。

26．在一種M的氧化物中，M與氧元素的質(zhì)量比為7：20，已知M與氧的相對(duì)原子質(zhì)量比

為7：8，則氧化物中M元素的化合價(jià)為。

27.吸入“笑氣”會(huì)使人發(fā)笑。該氣體是由氮、氧兩種元素組成的化合物，相對(duì)分子質(zhì)量為

44，氮、氧元素的質(zhì)量比為7：4，則它的化學(xué)式為。

28．某物質(zhì)化學(xué)式為HnRO2n-1，相對(duì)分子質(zhì)量為M，則R的化合價(jià)為，R的相對(duì)原子質(zhì)量為。

29．⑴某三價(jià)金屬氧化物中氧元素質(zhì)量分?jǐn)?shù)為30%，則該金屬的相對(duì)原子質(zhì)量為。

⑵A、B兩元素相對(duì)原子質(zhì)量之比為2∶1，僅由這兩種元素組成的化合物里，A、B兩元素

質(zhì)量比為2∶3，則該化合物的化學(xué)式為；若其中B為-n價(jià)，則此化合物中A元素的化合價(jià)為。

⑶元素R有多種氧化物，其中RO中含氧53.33%，那么相對(duì)分子質(zhì)量為76，含氧為63.15%的R的氧化物的化學(xué)式是。

30．使CO2和CO中含有相同質(zhì)量的氧元素，則CO2和CO的質(zhì)量比是；若CO

2和CO的質(zhì)量相等，則CO2和CO中的碳元素質(zhì)量比為。

31．有12克赤鐵礦的樣品，經(jīng)化驗(yàn)測(cè)定其中含F(xiàn)e5.88克，則此赤鐵礦中含F(xiàn)e2O3的質(zhì)量分

數(shù)為。

32．碘是人類健康必需的微量元素,能促進(jìn)人體的生長(zhǎng)發(fā)育,特別對(duì)大腦和神經(jīng)系統(tǒng)起著非常重要的作用。在食鹽中加入適量的碘酸鉀（KIO3），可以有效地防治碘缺乏病。KIO3的相對(duì)分子質(zhì)量為，KIO3中鉀元素、碘元素、氧元素的質(zhì)量比為，碘元素的質(zhì)量分?jǐn)?shù)為%。從去年起，我國(guó)食鹽中加碘含量將調(diào)整為每千克食鹽含碘0.035克，相當(dāng)于每千克食鹽含碘酸鉀克。

二、分析計(jì)算題

31.如圖是市售某品牌牙膏包裝盒上的部分說(shuō)明。

其主要活性成分單氟磷酸鈉（Na2 F PO3），是牙

膏常用添加劑之一，實(shí)驗(yàn)表明牙膏中單氟磷酸鈉的質(zhì)量分?jǐn)?shù)達(dá)到0.76%~0.80%時(shí)，防齲齒效果較好。

（1）求單氟磷酸鈉中氟元素的質(zhì)量分?jǐn)?shù)。

（2）通過(guò)計(jì)算判斷，該牙膏是否有較好的防齲齒效果

32．2010年3月22日是第18屆“世界水日”，3月22日至28日是第23屆“中國(guó)水周”。聯(lián)合國(guó)確定今年“世界水日”的宣傳主題是“健康用水，清潔世界”，我國(guó)確定的宣傳主題是“嚴(yán)格水資源管理，保障可持續(xù)發(fā)展”。明礬KAl(SO4)2·12H2O就是一種常用于水凈化的物質(zhì)，請(qǐng)回答下列問(wèn)題：（列式計(jì)算）

⑴ 明礬的相對(duì)分子質(zhì)量是多少？

⑵ 明礬中各元素的質(zhì)量比是多少？

⑶ 明礬中K元素的質(zhì)量分?jǐn)?shù)是多少？(計(jì)算結(jié)果精確到0.1％)

⑷ 258克明礬與多少克H2O所含的氧元素質(zhì)量相等？