为您找到与九年级下册化学第9单元知识总结相关的共200个结果:
失败乃成功之母,重复是学习之母。学习,需要不断的重复重复,重复学过的知识,加深印象,其实任何科目的学习方法都是不断重复学习。下面是小编给大家整理的一些九年级化学的知识点,希望对大家有所帮助。
1、分子是保持化学性质的最小微粒。原子是化学变化中的最小微粒。
2、元素是具有相同核电荷数(即质子数)的同一类原子的总称。
3、分子和原子的主要区别是在化学反应中,分子可分,原子不可分。
4、元素的化学性质主要决定于原子的最外层电子数。
5、在原子中,质子数=核电荷数=核外电子数。
6、相对原子质量=质子数+中子数
7、镁离子和镁原子具有相同的质子数或核电荷数。
8、地壳中含量最多的元素是氧元素。最多的金属元素是铝元素。
9、决定元素的种类是质子数或核电荷数。
10、空气是由几种单质和几种化合物组成的混合物。
11、石油、煤、天然气都是混合物。
12、溶液都是混合物。例如:稀硫酸、食盐水、石灰水等。
13、氧化物是由两种元素组成的,其中一种是氧元素的化合物。
14、化学变化的本质特征是有新物质生成。
15、燃烧、铁生锈、食物变质等都是化学变化。
16、化学反应的基本类型是化合反应、分解反应、置换反应、复分解反应。
17、金属活动性顺序表:KCaNaMgAlZnFeSnPb(H)CuHgAgPtAu
18、具有还原性的物质是H2、C、CO。其中属于单质的是C、H2。属于化合物的是CO。
19、燃烧、缓慢氧化、自燃的相同点是都是氧化反应。
20、在化学反应前后,肯定不变的是原子的种类和数目、元素的种类、反应前后物质的总质量。肯定变化的是物质的种类和分子的种类。
21、2H2表示两个氢分子;2H表示两个氢原子;2H+表示两个氢离子。
22、能鉴别氢氧化钠溶液、盐酸、水的试剂是石蕊试剂。
23、氢气是一种无色无味的气体,比空气轻,难溶于水。
24、二氧化碳是一种无色无味的气体,比空气重,能溶于水。
学习是把知识能力思维方法等转化为你的私有产权的重要手段,是“公有转私”的重要途径。你的一生,无法离开学习,学习是你最忠实的朋友,它会听你的召唤,它会帮助你走向一个又一个成功。下面给大家分享一些九年级下册化学知识点,希望对大家有所帮助。
高一化学学科必考知识点
有机化学基础知识点归纳总结
高二化学选修三知识点总结
生活中常见的盐
食盐的主要成分是NaCl,工业用盐如亚硝酸钠(NaNO2)有毒;碳酸钠(Na2CO3,俗称纯碱、苏打);碳酸氢钠(NaHCO3,又叫小苏打);大理石或石灰石的主要成分是CaCO3。
一、氯化钠:
1、用途:是重要的调味品;医疗上的生理盐水是用氯化钠配制的;公路上的积雪可以用氯化钠来消融。
2、粗盐提纯的步骤:(1)溶解:用玻璃棒搅拌,加速溶解;(2)过滤:玻璃棒引流;(3)蒸发:用玻璃棒不断搅拌,以防液滴飞溅;待蒸发皿中出现较多固体时,停止加热。
二、碳酸钠、碳酸氢钠和碳酸钙
1、用途:碳酸钠用于玻璃、造纸、纺织和洗涤剂的生产。碳酸钙是重要的建筑材料,还用作补钙剂。碳酸氢钠是发酵粉的主要成分,能治疗胃酸过多。
2、CO32-或HCO3-的检验方法:加盐酸,产生气泡;将气体通入澄清的石灰水,石灰水变浑浊。证明物质中有CO32-或HCO3-。
碳酸钠和盐酸反应 Na2CO3+2HCl==2NaCl+H2O+ CO2↑
碳酸氢钠与盐酸反应 NaHCO3 +HCl==NaCl +H2O +CO2↑
三、复分解反应
1、定义:由两种化合物互相交换成分,生成另外两种化合物的反应,叫做复分解反应。复分解反应中各元素的化合价一定不变。
2、复分解反应发生的条件:两种化合物互相交换成分,生成物中有沉淀或气体或水生成时,复分解反应才可以发生。盐和盐反应、盐和碱反应还要求反应物都可溶。
四、四种基本反应类型
化合反应、分解反应、置换反应、复分解反应。
一个人只有在早晨开始就努力学习,这一天才不会被浪费掉。我们每一个人都应该抓住每一分,每一秒,不让他们偷跑掉。同学们,请记住“成功,属于珍惜时间的人”,珍惜自己的时间,对你自己是有益的。下面给大家分享一些关于九年级化学下册知识点总结,希望对大家有所帮助。
第十单元 酸和碱
课题1 常见的酸和碱
石蕊和酚酞叫做酸碱指示剂,简称指示剂。紫色石蕊溶液遇酸溶液变红色,遇碱溶液变蓝色;无色酚酞溶液遇酸溶液不变色,遇碱溶液变红色。
一、常见的酸
1、盐酸无色、有刺激性气味的液体,有挥发性。打开浓盐酸,瓶口有白雾。用于金属除锈,人的胃液里有盐酸,可以帮助消化。
2、硫酸是无色、油状液体,不挥发。浓硫酸有吸水性,常做干燥剂(不能干燥氨气),用于金属除锈。
3、浓硫酸有强烈的腐蚀性。能夺取纸张、木材、皮肤、衣服里的水分,生成黑色的炭。
4、浓硫酸溶于水时放出大量的热。在稀释浓硫酸时,一定要把浓硫酸沿器壁慢慢注入水中,并不断搅拌。切不可把水倒进浓硫酸里。否则会使硫酸液滴向四周飞溅。
5、浓硫酸沾到皮肤或衣服上,应立即用大量水冲洗,然后涂上3%~5%的碳酸氢钠溶液。
6、酸的化学性质
由于酸溶液中都有H+,所以酸有相似的化学性质。
(1)酸能与指示剂反应,使紫色石蕊溶液变红,使无色酚酞不变色;
(2)酸能与多种活泼金属反应,生成盐和氢气;
(3)酸能与某些金属氧化物反应,生成盐和水;
(4)酸和碱能发生中和反应,生成盐和水
(5)酸能与某些盐反应,生成另一种酸和另一种盐。
铁锈与盐酸反应: Fe2O3 + 6HCl == 2FeCl3 + 3H2O
铁锈与稀硫酸反应:Fe2O3 + 3H2SO4== Fe2(SO4)3+ 3H2O
铁锈与盐酸或稀硫酸反应的现象:铁锈逐渐消失,溶液由无色变为黄色。
二、常见的碱。
1、氢氧化钠
(1)、氢氧化钠俗名苛性钠、火碱或烧碱,有强烈的腐蚀性,如果沾到皮肤上,要用较多的水冲洗,再涂上硼酸溶液。
(2)、氢氧化钠是白色固体,易溶于水,放出大量热。有吸水性,在空气中易潮解,常做干燥剂(不能干燥CO2、SO2、HCl)。氢氧化钠可除油污,如炉具清洁剂中就含有氢氧化钠。
(3)氢氧化钠在空气中不仅吸收水分而发生潮解(物理变化),还能和CO2反应而发生变质(化学变化),所以必须密封保存。
氢氧化钠与二氧化碳反应 2NaOH + CO2 == Na2CO3 + H2O
(4)工业上制氢氧化钠:Na2CO3+Ca(OH)2== CaCO3↓+2NaOH
2、氢氧化钙
(1)氢氧化钙俗名熟石灰、消石灰,是白色固体,微溶于水。氢氧化钙可做建筑材料、可以改良酸性土壤。氢氧化钙的水溶液俗称石灰水,可用来检验二氧化碳。
(2)生石灰与水反应可制熟石灰,反应放出大量的热:
CaO + H2O == Ca(OH)2 生石灰可做干燥剂。
3、碱的化学性质
由于碱溶液中都有OH-,所以碱有相似的化学性质。
(1)碱溶液能与指示剂反应,使紫色石蕊变蓝色,使无色酚酞变红色。
(2)碱能与某些非金属氧化物反应,生成盐和水。
(3)碱和酸能发生中和反应,生成盐和水。
(4)碱能与某些盐反应,生成另一种碱和另一种盐。
课题2 酸和碱之间会发生什么反应
一、中和反应
1、由金属离子(或NH4+)和酸根离子构成的化合物叫做盐。
2、酸与碱作用生成盐和水的反应叫做中和反应,属于复分解反应。
氢氧化钠与盐酸的中和反应 NaOH + HCl == NaCl + H2O
氢氧化钠与硫酸的中和反应 2NaOH + H2SO4== Na2SO4+2H2O
二、中和反应在实际中的应用
在酸性土壤中加入熟石灰,以中和酸性;硫酸厂的污水中有硫酸,可以用熟石灰中和;胃酸过多,可服用含有碱性物质的药物;被蚊虫叮咬后(蚊虫能分泌蚁酸),可涂上含有碱性物质(如NH3.H2O)的药水。
三、溶液酸碱度的表示法——pH
1、检验溶液的酸碱性,用酸碱指示剂。
2、表示溶液的酸碱度,用pH,pH的范围在0~14之间。酸性溶液的pH<7;碱性溶液的pH>7;中性溶液的pH=7。
3、测定pH最简便的方法是使用pH试纸。
4、测定pH的方法:在白瓷板或玻璃片上放一小片pH试纸,将待测液滴到pH试纸上,把试纸显示的颜色与标准比色卡比较。即可得出溶液的pH。
5、农作物一般适宜在pH为7或接近7的土壤中生长;因溶解有二氧化碳,正常雨水的pH约为5.6,酸雨的pH< 5.6。
一、空气成分的研究史
1.18世纪70年代,瑞典科学家舍勒和英国的科学家化学家普利斯特里,分别发现并制得了氧气。
2.法国科学家拉瓦锡最早运用天平作为研究化学的工具,用定量的方法研究了空气的成分,第一次明确提出了“空气是由氧气和氮气组成的”。其中氧气约占空气总体积的1/5的结论。
二、空气中氧气成分的测定
1.实验现象:
A.红磷燃烧发出黄白色火焰,放出热量,冒出白色浓烟
B.(过一会儿白烟消失,装置冷却到室温后打开弹簧夹)烧杯内的水倒流入集气瓶,约占瓶子容积的1/5。
2.实验结论:说明空气不是单一的物质;氧气约占空气总体积的1/5。
3.原理
4.注意事项:
A.所用的红磷必须过量,过少则氧气没有全部消耗完
B.要等集气瓶(装置)冷却后才能打开弹簧夹,
C.装置的气密性要好,(否则测量结果偏小),
D.要先夹住橡皮管,然后再点红磷(否则测量结果偏大)。
E.点燃红磷伸入瓶中要立即塞紧瓶塞(否则测量结果偏大)。
思考:
(1)可否换用木炭、硫磺、铁等物质?如能,应怎样操作?
答:不能用木炭或蜡烛(燃烧产生了气体,瓶内体积变化小),不能用铁(铁在空气中不能燃烧)
(2)可否用镁代替红磷?不能用镁,因为镁不但跟氧气反应而且还跟氮气等反应,结果测得的不只是空气中氧气的体积。会远远大于氧气的体积。
5..实际在实验中测得的结果比真实值小,其原因可能是A.红磷量不足;B.装置气密性差;C.未冷却至室温就打开止水夹;D.没有预先在导管中装满水
三、空气的主要成分
(按体积分数):氮气(N2)78%,氧气(O2)21%(氮气比氧气约为4:1),稀有气体0.94%,二氧化碳(CO2)0.03%,其它气体和杂质0.03%。空气的成分以氮气和氧气为主,属于混合物。
空气成分口诀:氮七八氧二一,零点九四是稀气;零点零三有两个,二氧化碳和杂气
四、物质的分类:纯净物和混合物
1.纯净物:由一种物质组成的,“纯净”是相对的,绝对纯净的物质是没有的,只要杂质含量低,不至于对生产和科学研究产生影响的物质就是纯净物。
2.混合物:两种或多种物质组成的,这些物质相互间没有发生化学反应,各物质都保持各自的性质。
注意:划分纯净物、混合物的标准是根据物质的种类来划分的。只含一种物质的就属于纯净物,含有几种物质的就属于混合物
五、空气是一种宝贵的资源
1.氮气:无色、无味的气体,不溶于水,不燃烧也不支持燃烧,不能供给呼吸,化学性质不活泼。
2.稀有气体:无色、无味的气体,通电时能发出不同颜色的光,化学性质很不活泼。
六、空气的污染及防治
1.造成空气污染的物质:有害气体(一氧化碳(CO)、二氧化氮(NO2)、二氧化硫(SO2))和烟尘。
2.污染来源:空气中的有害物质来自化石燃料的燃烧,石油化工厂排放的废气及汽车排放的尾气。
3.被污染的空气带来的危害:损害人体健康、影响作物生长、破坏生态平衡。
存在的环境问题:温室效应(二氧化碳含量过多引起)、臭氧空洞(飞机的尾气、氟里昂的排放)、酸雨(由二氧化硫、二氧化氮引起)。
4.防止空气污染的措施:加强大气质量监测,改善环境状态、植树造林、使用清洁能源。
5.目前空气污染指数包括:一氧化碳、二氧化氮、二氧化硫、可吸入颗粒物、臭氧。
七、未来化学将朝着“绿色化学”——“绿色消毁”和“绿色生产”的方向发展。核心是利用化学原理从源头消除污染。
特点:①充分利用资源和能源,原料无毒无害②减少向环境排放废物③原料中的原子全部被消纳,实现零排放(在化合反应中体现)④生产出环境友好产品。
氧气
一、氧气的物理性质
1.色、味、态:通常情况下,是无色无味的气体;
2.密度:标准状况下,密度为1.429g/L,略大于空气。(可用向上排空法)
3.溶解性:氧气不易溶于水。(可用排水法收集)
4.三态变化:降温后,氧气可以变为淡蓝色的液体,甚至淡蓝色雪花状固体。
二、氧气的化学性质
(一)与非金属(碳、硫、磷)的反应
1.木炭(黑色固体)燃烧
实验现象:在氧气中:剧烈燃烧,发出白光,放出热量,生成一种无色无味气体,该气体能使澄清石灰水变浑浊。
做木炭燃烧实验时,燃烧匙应慢慢从瓶口向瓶底伸入(充分利用瓶内的氧气)。
2.硫粉(淡黄色)燃烧:
实验现象:在空气中:发出微弱的淡蓝色火焰;放出热量、生成一种带有刺激性气味的气体。
在氧气中: 发出明亮的蓝紫色的火焰, 放出热量、生成一种带有刺激性气味的气体。
实验时,要在瓶底装少量水)吸收二氧化硫,防止污染空气)。
3.红磷(暗红色固体)的燃烧
实验现象:在空气中:发出黄白色火焰,放出热量,生成大量白烟
在氧气中:剧烈燃烧,发出白光,放出热量,生成大量的白烟
注意:五氧化二磷(P2O5)是固体,不是气体
(二)与金属(镁、铁)的反应
1.镁带(银白色固体)在空气中燃烧
实验现象:剧烈燃烧,发出耀眼的白光,放出热量,生成白色粉末状固体。
2铁丝(银白色固体)在氧气中燃烧
实验现象:剧烈燃烧,火星四射,放出热量,生成一种黑色固体。
注意:集气瓶底部铺少量的细沙或加少量的水,防止生成的固体物质溅落瓶底,致使集气瓶炸裂。铁丝在空气中不能燃烧
(三)与某些化合物(蜡烛、甲烷)的反应——产物均为:二氧化碳和水
实验现象:比空气中燃烧剧烈,发出白光,集气瓶内壁出现水珠,有使澄清石灰水变浑浊的无色无味气体产生。
空气中燃烧情况:燃烧产生黄色火焰,放热,稍有黑烟。
(四)其他物质与氧气的反应
某些物质在一些条件下,与氧气发生缓慢的氧化反应,成为缓慢氧化。缓慢氧化也放热。
如:动植物新陈代谢,金属的锈蚀,食物的腐烂、酒醋的酿造、农家肥的腐熟等等。
总结:
1.氧气是一种化学性质比较活泼的气体,在一定的条件下,能与许多物质发生反应并放出大量的热。在这些反应中,氧气提供氧,称为氧化反应。氧气便是常见的氧化剂;具有氧化性。
2.物质在纯氧气中燃烧程度比空气中燃烧要剧烈。说明物质燃烧程度,与氧气的浓度大小成正比;
3.物质燃烧时有的有火焰,有的会发光,有的会冒烟。一般来说,气体燃烧会有火焰产生,固体直接燃烧,产生光或者火星。生成物有固体,一般都会产生烟,即固体小颗粒;
4.物质与氧气反应不一定是燃烧现象,如缓慢氧化。
三、氧气的用途
(1)供给呼吸:医疗上急救病人,登山、潜水、航空、宇航提供呼吸;
(2)支持燃烧:炼钢、气焊与气接、液氧炸弹、火箭助燃剂
实验室制取氧气
一、工业制法(分离液态空气法)
原理:利用液态氧和液态氮的沸点不同。——物理变化(蒸馏)
(1)具体过程
(2)注意:该过程是物理变化
二、氧气的实验室制法(化学变化)
1.双氧水(过氧化氢)制取氧气
A.药品:过氧化氢(H2O2)和二氧化锰(黑色粉末 MnO2)
B.实验原理:
注:MnO2在该反应中是催化剂,起催化作用
C.装置: 固体与液体反应,不需加热(双氧水的为一类)
注意事项:
①分液漏斗可以用长颈漏斗代替,但其下端应该伸入液面以下,防止生成的气体从长颈漏斗中逸出;
②导管只需略微伸入试管塞
③气密性检查:用止水夹关闭,打开分液漏斗活塞,向漏斗中加入水,水面不持续下降,就说明气密性良好。
④装药品时,先装固体后装液体
⑤该装置的优点:可以控制反应的开始与结束,可以随时添加液体。
D步骤:连、查、装(二氧化锰)、定、倒(过氧化氢溶液)、收
2.用高锰酸钾、氯酸钾制取氧气
A.药品:、高锰酸钾(暗紫色固体)、氯酸钾(白色固体)与二氧化锰(黑色粉末)
B.原理:
①加热氯酸钾(有少量的二氧化锰):
注意:MnO2在该反应中是催化剂,起催化作用
② 加热高锰酸钾:
C.装置:加热固体制气体(加热氯酸钾的为一类)
D.操作步骤:(连)查、装、定、点、收、离、熄。
① 连接装置:先下后上,从左到右的顺序。
② 检查装置的气密性 :将导管的一端浸入水槽中,用手紧握试管外壁,若水中导管口有气泡冒出,证明装置不漏气。松开手后,导管口出现一段水柱。
③ 装入药品:按粉末状固体取用的方法(药匙或纸槽)
④固定装置 :固定试管时,试管口应略向下倾斜;铁夹应夹在试管的中上部
⑤加热药品:先使试管均匀受热,后在反应物部位用酒精灯外焰由前向后加热。
⑥收集气体:
a.若用排水集气法收集气体,当气泡均匀冒出时再收集,刚排出的是空气;水排完后,应用玻璃片盖住瓶口,小心地移出水槽,正放在桌面上(密度比空气大)(防止气体逸出)
b.用向上排空法。收集时导管应伸入集气瓶底部(为了排尽瓶内空气)
用排水法收集时,导管放在集气瓶口
⑦先将导管移出水面
⑧再停止加热
E.易错事项:
(1)试管口要略微向下倾斜:防止生成的水回流,使试管底部破裂。药品应平铺在试管底部
(2)导气管伸入发生装置内要稍露出橡皮塞:有利于产生的气体排出。
(3)用高锰酸钾制取氧气时,试管口塞一团棉花:防止高锰酸钾粉末进入导气管,污染制取的气体和水槽中的水。
(4)排气法收集气体时,导气管要伸入接近集气瓶底部:有利于集气瓶内空气排出,使收集的气体更纯。
(5) 实验结束后,先将导气管移出水面,然后熄灭酒精灯:防止水槽中的水倒流,炸裂试管。
F、收集方法:
① 排水法(不易溶于水)
② 向上排空法(密度比空气大)
G、检验、验满
检验:用带火星的木条伸入集气瓶内,发现木条复燃,说明是氧气;
验满:用带火星的木条放在集气瓶口,若木条复燃,证明已满。
三、催化剂
1.概念:在化学反应中能改变其他物质的反应速率(加快或变慢),但本身的化学性质和质量在反应前后没有发生变化的物质。
2.特点:两不变(质量、化学性质)、一改变(反应速率)
注意:①催化剂不能改变生成物的质量,不能决定反应的进行
②催化剂不是反应物、又不是生成物
③催化剂仅针对某一反应,并不是所有反应的催化剂
④某一反应的催化剂可能不只一种
3.二氧化锰在一些反应中不只作催化剂,催化剂不一定就只有二氧化锰。(在过氧化氢溶液制取氧气中,催化剂可以用硫酸铜溶液、氧化铁、氧化铜、红砖粉末)。在氯酸钾制取氧气中,二氧化锰的质量和化学性质不变,但质量分数变大。
碳和碳的氧化物是九年级化学第六单元知识点,你都掌握了吗?下面是百文网小编为你整理的九年级化学第六单元知识点,一起来看看吧。
在九年级这个阶段,学好化学可以为高中的学习打好基础,那么关于九年级化学知识点有哪些呢?以下是小编准备的一些九年级化学下册知识点总结归纳,仅供参考。
层次一:物质的再认识
由于专题“初识酸碱盐”的内容主要是学习置换反应、复分解反应及条件和物质间相互转化关系,其涉及的物质种类多,且颜色状态不一。因而认识初中化学中常见的、重要的物质是最关键的。
建议学生进行归纳、再认识二指示剂:紫色石蕊溶液、无色酚酞溶液;三酸:稀硫酸、盐酸、硝酸;五氧化物:氧化铜、氧化铁、氧化钙、二氧化碳、二氧化硫;七碱:氢氧化钠、氢氧化钾、氢氧化钙、氢氧化钡、氢氧化铜、氢氧化铁、氢氧化镁;十三盐:氯化钠、碳酸钠、碳酸钾、碳酸氢钠、氯化铁、硫酸铜、硝酸铵、硫酸铵、碳酸氢铵、碳酸钙、碳酸钡、氯化银、硫酸钡。归纳、认识以上物质时注意它们的颜色、状态、溶解性及其对应水溶液的颜色,掌握物质分类的知识和技能。
层次二:物质间的反应关系
以一种酸或碱或盐归纳其物理性质和化学性质,然后拓展到其他同类物质,最后总结出酸的性质、碱的性质和盐的性质,进而总结出物质间相互转化的关系,并进一步认识物质的用途。这个层次的复习主要以书写化学方程式为主,借以轻松地掌握重要的.酸、碱、盐的化学性质。
层次三:概念的认识及反应规律
1、认识概念:一个条件:复分解反应条件;两种反应类型:置换反应、复分解反应;三种干燥剂:氢氧化钠、浓硫酸、生石灰;四个概念的理解:酸(碱)性溶液、溶液的酸碱度、中和反应、潮解;五类复分解反应:酸与金属氧化物反应、酸与碱反应、酸与盐反应、碱与盐反应、盐与盐反应。
2、反应规律:复分解反应的生成物中至少有气体、沉淀、水中的一种;碱与盐反应、盐与盐反应,反应物都必须溶于水;在复分解反应中生成的气体是二氧化碳和氨气(常见的是二氧化碳);复分解反应中生成物是碳酸时要写出二氧化碳和水,是氢氧化铵时要写出氨气和水;硫酸盐能转化成盐酸盐和硝酸盐,盐酸盐能转化成硝酸盐,反之则不可以;金属与盐反应前置后盐必溶、单质铁、变二价、钾钙钠都不行;金属和盐溶液混合充分反应后,过滤,得到的固体和滤液,金属活动性由不活泼的到活泼的在固体中依次出现,而滤液中则是由活泼到不活泼的依次出现(金属包括金属单质和盐中的金属元素),以上的内容需要很好地理解并特殊记忆。
层次四:物质的应用
通过前三个层次的复习,学生对酸、碱、盐的认识已较为深刻了。此时应该将内化的知识转化为外化的实践,即对物质的性进行应用,如进行物质的鉴别、物质除杂、物质的推断等实践应用,并在实践中寻找规律、把握技巧和方法,也可让自己做一些具有创造性的工作,如探寻一些物质的制备方法等。通过这一复习途径,可以进一步挖掘自己的潜能,培养自己的创新精神和创造能力。
在初三阶段,学好化学的每一个基础知识点吧。那么关于九年级化学上册第四单元知识点都有哪些呢?以下是小编准备的一些九年级上册化学第四单元知识点总结,仅供参考。
1、重视课堂学习。课上是获取初中化学知识的主要途径,课上是决定学习的关键,所以初中生在课堂上面一定要认真听课,听课不仅仅是你人坐在椅子上面,一定是要眼睛、脑袋和耳朵并用,这样的课堂听课效率才能够提高。对于老师讲到的重点和难点,一定要先仔细听,然后认真做笔记,老师多次强调的知识点也要记录下来。
2、重视化学实验。我们知道化学是一门以实验为主的学科,对于初中化学的概念和一些定理其实都是在实验的基础上面得来的,所以初三学生想要学好化学就一定要重视实验,那么这就需要学生对于化学仪器的名称牢记,掌握使用方法,教材上面的实验更要牢记于心。
3、及时复习。在初中阶段化学最多的就是记忆,所以初三化学的学习一定要及时复习,课本上面的知识点和一些化学方程式,这些都是需要背诵和记忆的。课后复习的时候对于不能及时解决的问题,要熬记录下来,这样便于理解、记忆及应用。
化学是中考的必考科目,我们想要学好化学,一定要找对方法。那么关于九年级化学知识点怎么学习呢?以下是小编准备的一些人教版九年级下册化学知识点总结,仅供参考。
一、单项选择题(本题包括10个小题,每小题2分,共20分。每小题有四个选项,其中只有一个选项符合题意) 1.A 2.D 3.C 4.A 5.B 6.C 7.C 8.A 9.C 10.B
二、选择填充题(本题包括5个小题,每小题3分,共15分。先在A、B、C中选择一个正确选项,然后在D处再补充一个符合的答案。每小题的选择2分,填充1分)
11 B氯化钠等12 C HCl CaCO3 13.C 加水14 C为加快固体溶解,用玻璃棒搅拌(合理即可) 15 A 溶液中溶质的质量分数
三、填空与简答题(本题包括5个小题,共30分)
16 Ca(OH2) KMnO4 C2H5OH H2SO4 NaCl I2
17.① B; ②甲;③升温(加水);④t1℃时甲和乙的溶解度相等; ⑤33.3%; ⑥BD.
18. ① 升高 A ②100w/(100+w) ③在压强为101kPa和温度为0℃时,1体积水里最多能溶解0.024体积的氮气。(2分)
19.(1)A (2)D (3)9.1 g (漏写单位不得分)(4)< (5)降温结晶,过滤 (2分)
20. ⑴t1 ⑵乙 ⑶降温结晶(合理均可)⑷大于
⑸ ①B ②甲物质溶于水时会放出热量,使溶液温度升高,甲物质的溶解度增大。
四、实验题(本题包括3个小题,共25分)
21(每空2分)(1)无法判断(2) ②③⑥(3)量筒和玻璃棒
22(5分)(1)36 (2)< (3)蒸发结晶 (4)氢氧化钠溶于水放热,而氢氧化钙的溶解度随温度的升高而逐渐减小,所以结晶析出(2分)
23(每空2分)(1)30 23 (2)4 36 (3)A (4)BC (6)1.063
五、计算题(本题包括1个小题,共10分)
24(1)乙
解:H2为 167.5-167.1=0.4g
设有XgZn与YgH2SO4反应,生成zgZnSO4得.
Zn + H2SO4 ==== ZnSO4 + H2↑
65 98 161 2
X Y Z 0.4g
65:98:161:2=X:Y:Z:0.4g
解之得:X=13g Y=19.6g Z=32.2g
(2) 13g/15g×100%=86.7%
(3)19.6g/(152.5-52.5)g×100%=19.6%
(4)32.2g/(100+13-0.4)g×100%=28.6%
答:略
人教版六年级下册语文第二单元知识点总结
学完一个单元,都要进行单元知识点汇总,那么关于人教版六年级下册语文第二单元知识点怎么学习呢?以下是小编准备的一些六年级下册语文第二单元知识点,仅供参考。
一、真挚、唾沫、侮辱、灌溉
整体认读音节:挚、侮
二、 hé、 pèn 、 xù、 yāo、 qiè
三、
负(荆)请罪 高瞻远(瞩) 解(囊)相助 兔死(狐)悲
响(遏)行云 同心(协)力 (截)然不同 开卷有(益)
四、D
五、A
六、
1、落红不是无情物,化作春泥更护花
2、不识庐山真面目,只缘身在此山中。
3、八仙过海各显神通
4、海内存知己,天涯若比邻(答案不确定)
5、少小离家老大回,乡音不改鬓毛衰
6、独在异乡为异客,每逢佳节倍思亲
7、赠人玫瑰,手有余香
8、横眉冷对千夫指,俯首甘为孺子牛
9、人生自古谁无死,留取丹心照汗青
10、少壮不努力,老大徒伤悲
七、
1、寒冷 饥饿 也没有痛苦的地方去了 卖火柴的小女孩 小说 童话之父
2、被微风吹散了 薄雾 朱自清 浪花(头发) 被海涛淹没了(被岁月染白了)
3、蔺相如 机智勇敢、顾全大局 廉颇 知错就改 完璧归赵 渑池之会 负荆请罪
八、
1、我听到旋律。
2、谁都说武松是个机智勇敢、武艺高强的英雄。
3、因为土壤里会有水分和养料,所以作物能生长。
4、难道我们能罔极这十多年父母对我们的养育之恩吗?
5、我们要发扬艰苦奋斗的光荣传统。
九、
1.匀称、称赞
2.谦虚、气魄、吸吮
批评、开心、垂头丧气
3.,:“?!,,。!”。
4.因为它老是仰着脸,想尽量把自己的枝﹑杈把弄得比老柳树漂亮一些。一天到晚得意洋洋地欣赏自己的美貌。本来主人是打算用它做房梁的,可现在除了把它当做柴火烧掉,再也没有别的用处了。
5.略
6.略
人教版九年级下册英语第七单元单词及知识点
英语是按照分布面积而言最流行的语言,但母语者数量是世界第三,仅次于汉语、西班牙语。那么九年级下册英语怎么学习呢?以下是小编准备的一些九年级下册英语第七单元单词及知识点,仅供参考。
一、指导思想
在本学期的英语教学中,坚持以下面的教学理念为指导:第一,切实地了解学生的真实水平,注意衔接,尽快使学生适应我的英语教学;第二,教学要面向全体学生,关注学生的情感,激发他们学习英语的兴趣;第三,以学生为主体,尊重个体差异,因材施教;第四,在新课标的指导下,倡导学生体验参与学习,完成设计目标;第五,注重过程性评价, 建立能鼓励学生自主学习能力发展提高的综合评价体系。
二、学生情况分析
本届学生在英语基础方面很薄弱,由于在以前学习英语的过程中,没有很详细全面地学习音标,基本的音标和字母拼读都没有掌握好。在词汇,语法规则等方面存在很多缺漏。所以,在听、说、读、写这四项技能上,学生水平存在很大差异。
另外,学生在学习策略和情感态度方面也存在诸多需要进一步解决的问题。例如:许多学生不能明确学习英语的目的,学习缺乏主动性、自觉性;大多数同学没有养成良好的学习习惯,不能做好课前预习和课后复习工作,学习没有计划性和策略性,也不注意知识的积累和巩固。
最后,学生对新教材缺乏一定程度上的了解,还不适应新课改指导下的一些教学方法。在课堂上,习惯像以往被动地接受所传授的知识,不善于发现和总结语言规律,学习的主体性不突出。
三、教材与教辅的分析
1、 内容与结构
每一单元除了关注阅读、写作、听力、视听说等语言实践活动,还关注语言知识、情感态度、文化意识和学习策略等。其中,教材加强了文化意识的提高和学生学习策略的培养,是相较于以前教材很大的不同。
2、教材的特点
首先突出学习者的发展,包括注重学习策略的培养和使用;注重提高学生的语言认知能力;为教师和学生提供个性化的选择;其次努力提高学生用英语进行思维和表达的能力。具体为:为学生提供更多的体验真实语言的机会;精心设计教学活动,使学生看到明确的目标和明确的成果;为学生发展语言运用能力提供详尽的语言支持;重视复现。
3、教材的重难点
该套教材强调学生综合语言运用能力的培养和提高,所以重点在于培养学生用英语获取信息、处理信息的能力;用英语分析问题、解决问题的能力;用英语进行思维和表达的能力。难点在于学生在情感态度和学习策略上的改变,达到用英语思维和表达的目标。
4、教学目标
⑴总体目标:激发学生学习英语的兴趣,树立自信心。在整个教学过程中,让学生有丰富的生活常识、多文化背景的积累,并形成正确人生观、价值观,有积极的情感态度和跨文化的交际能力。同时培养自主学习能力,积累学习方法。
⑵具体目标:结合学生基础知识过于薄弱的实际,在教学刚开始的阶段,注意高一和初中知识的衔接,例如复习音标和字母拼读规律,积累基础词汇、词语搭配、句型,熟悉不同单元呈现的语法规则,掌握实际用法。希望第一学期后,学生能培养学习的兴趣,养成较好的学习习惯,对基础知识有一定的掌握。
5、教学措施
⑴让学生每天积累几个单词,利用“互测及教师抽查”及时检查,保证效果并坚持下去。
⑵认真贯彻晨读制度:规定晨读内容,加强监督,保证晨读效果。
⑶实行过程性评价,调动学生积极性,通过不同方式的检测,让进步的同学体会到成就感,让落后的同学找出差距,感受压力。由此在班里形成浓厚的学习氛围,培养学生健康向上的人格和竞争意识。
⑷ 关注学生的情感,营造宽松、民主、和谐的教学氛围。
⑸在教学中根据目标并结合教学内容,创造性地设计贴近学生实际的教学活动,吸引和组织他们积极参与。学生通过思考、调查、讨论、交流和合作等方式,学习和使用英语,完成学习任务。
⑹经常进行教学反思,适时调整教学方法,符合学生的真实情况,利于学生的有效性学习。
从所任课班级实际情况和本身条件出发,认真进行思考和改正。多关注学科教研的发展,多多听课向有经验的老师虚心学习,取之所长,多和同事交流探讨,交换教学思想和方法,避己所短,不断进步。积极参与学科的相关课题研究,撰写论文,参加教研组,备课组的教研活动。
九年级下册英语第八单元单词及知识点
英语是学习最广泛的第二语言,是近60个主权国家的官方语言或官方语言之一。与英语为母语的人相比,将其作为第二语言学习的人更多。以下是小编准备的一些九年级下册英语第八单元知识点,仅供参考。
第Ⅰ卷(共95分)
Ⅰ. 听力测试。(共30分)
第一节(每小题1.5分,共9分)
听一遍。根据你所听到的句子,从A、B、C三个选项中选出最恰当的答语,并把答题卡上对应题目的答案标号涂黑。
1. A. Thank you. B. I hope so. C. Nice to meet you, too.
2. A. It’s blue. B. They are black. C. It’s beautiful.
3. A. Yes, I do. B. Yes, you do. C. No, we have.
4. A. Not at all. B. My pleasure. C. Sorry, you may.
5. A. Come on! B. Of course not. C. Have a nice trip!
6. A. I’m well. B. I have a cold. C. It doesn’t matter.
第二节(每小题1.5分,共9分)
听一遍。根据你所听到的对话和问题,从A、B、C三个选项中选出正确答案,并把答题卡上对应题目的答案标号涂黑。
7. A. 12. B. 20. C. 21.
8. A. Working. B. Sleeping. C. Playing.
9. A. Today. B. Tomorrow. C. Next Friday.
10. A. Laura’s. B. Jason’s. C. Mike’s.
11. A. In New York. B. In China. C. In Canada.
12. A. By subway. B. By bus. C. By taxi.
第三节(每小题1.5分,共6分)
听两遍。 根据你所听到的长对话,从A、B、C三个选项中选出正确答案,并把答题卡上对应题目的答案标号涂黑。
听下面一段材料。回答 13和14小题
14. Which team will the school set up?
A. A soccer team. B. A swim team. C. a basketball team.
13. How many students will be chosen from each class?
A. One. B. Two. C. Three.
听下面一段材料。回答15和16小题
15. What’s wrong with the boy?
A. He has a cold. B. He has a fever. C. He has a headache.
16. What’s the relationship between the two speakers?
A. Doctor and patient. B. Teacher and student. C. Mother and son.
第四节(每小题1.5分,共6分)
听两遍。 根据你所听到的短文内容,从A、B、C三个选项中选出正确答案,并把答题卡上对应题目的答案标号涂黑。
17. The shopping center is the _________ in the city.
A. biggest B. newest C. nicest
18. You can find children’s clothes _________.
A. on the 2nd floor B. on the 3rd floor C. on the 4th floor
19. You can _________ on the 6th floor.
A. buy gentlemen’s clothes B. ladies’ shoes and hats C. have dinner
20. If you want to have a free drink, you need to pay over _________ at one time.
A. $25 B. $50 C. $75
Ⅱ.单项选择。(每小题1分,共20分)
从A、B、C、D四个选项中选出可以填入空白处的答案,并把答题卡上对应题目的标号涂黑。
21. Zootopia is _________ best cartoon that I have ever seen in my life.
A. a B. an C. the D. /
22. When I was a teenager, I often went to school _________ bike.
A. with B. on C. in D. by
23. We should take good care of _________ when we are in foreign countries.
A. us B. our C. ours D. ourselves
24. People must try everything to stop our earth from _________.
A. polluting B. polluted C. being pollution D. being polluted
25. — How do you like the new Ipad Pro?
— _________. But the price is high.
A. I know it B. It’s useful C. It’s expensive D. I think so
26. We don’t think English homework is too much _________.
A. to finish it B. to finish C. to finishing it D. to finishing
27. As we all know, the world population has _________ to 6 billion. It is really a big number.
A. produced B. provided C. increased D. invented
28. — Will you go to the special party held by our English club?
— Oh, I _________ unless I am a VIP. So the answer is no.
A. was invited B. wasn’t invited C. will be invited D. won’t be invited
29. I’m sure that there _________ a key and two cards on the desk minutes ago, but there’s nothing now.
A. is B. are C. was D. were
30. Excuse me, could you please help me _________ the time of the next train to Beijing.
A. look for B. look out C. look up D. look after
31. My parents and teachers always encourage me _________ what I like.
A. do B. did C. to do D. doing
32. Everyone needs to make a _________ on their life journey, because what they choose will influence their future.
A. choice B. difference C. mistake D. discussion
33. — I am just wondering _________.
— Nothing serious. I just have a sore back.
A. what you happen B. what is wrong with you
C. what the matter is with you D. what wrong is with you
34. Sorry, Jack. I wasn’t at home at that time when you phoned me. I _________ the acting class in the school.
A. will take B. was taking C. am taking D. have taken
35. — Michael, please don’t watch TV while eating dinner. It’s bad for your eyes.
— _________, Mom.
A. OK, I will B. Sorry, I won’t C. Of course D. You’re welcome
36. He keeps exercising every day _________ cold it is outside.
A. however B. whenever C. whoever D. whatever
37. — Need I go shopping with you, mom?
— No, you _________. You can hang out with your friends.
A. needn’t B. can’t C. shouldn’t D. mustn’t
38. __________! It makes my eyes feel uncomfortable.
A. How strong light B. How a strong light
C. What a strong light D. What strong light
39. I don’t think there will be _________ fresh water and clean air in the future than now because people don’t see the importance of environmental protection.
A. much B. more C. less D. fewer
40. — Excuse me, where is the nearest bookstore?
— It’s _________ to the middle school, but it _________ for a few days.
A. close; has closed B. close; has been closed
C. closed; has been closed D. closed; has been close
Ⅲ. 完形填空。 (每小题1.5 分,共15分)
从A、B、C、D四个选项中选出可以填入空白处的答案,并把答题卡上对应题目的标号涂黑。
As traditional Chinese art, paper cutting has a long history. The first and earliest paper cutting was found in China 1500 years ago. But this traditional art is disappearing now. 41 , Voyo Woo, a Chinese woman living in America, is trying to 42 this art back to life.
One Saturday in 2014, Ms. Woo held a paper cutting show at a shopping center near Washington. She had much fun 43 it and hoped more and more people would enjoy it.
Ms. Woo has been studying the art of paper cutting 44 she was a junior high school student in her hometown. She said all the students at school had to learn paper cutting. Because she had a 45 love for it, her teacher spent a lot more time teaching her after class. Later, she won the second prize in a national painting and art competition.
Ms. Woo went to America after she graduated from the university in 2008. Soon after that, she 46 an activity to promote (宣传) Chinese paper cutting. And then she was again invited to show the art in many other important 47 . “I love what I am doing and I will keep on doing it as much as possible. It is important to promote this art to Americans or 48 who is interested in it. Maybe it will make this art more popular.” Woo said.
From the 49 of paper cutting, people can know about Chinese cultural values, history and stories of people’s life. Ms. Woo uses the art as a tool to show Chinese culture 50 people who know little about it. Chinese art is not only for Chinese, but also all for people all over the world.
41. A. Especially B. Instead C. Luckily D. Usually
42. A. bring B. take C. carry D. hold
43. A. to do B. doing C. done D. having done
44. A. after B. since C. when D. if
45. A. widely B. wide C. deeply D. deep
46. A. gave up B. held on C. found out D. took part in
47. A. activities B. meetings C. matches D. competitions
48. A. people B. anyone C. every one D. no one
49. A. characters B. colors C. art D. spirit
50. A. for B. to C. with D. from
九年级下册英语第九单元单词及知识点整理归纳
自17世纪以来,现代英语在英国和美国的广泛影响下在世界各地传播。那么关于九年级下册英语怎么学习呢?以下是小编准备的一些九年级下册英语第九单元单词及知识点,仅供参考。
一、指导思想:
__年中考在即,我将本着以《英语课程标准》为依据,以考纲为标准,以教材,指导丛书,复习指导为具体内容,根据国家提出的素质教育的要求,结合我校实际情况,我们备课组经过讨论,制订了周密的复习计划,并组内自己出《中考复习课时计划》,领学生进行全面复习,稳打稳扎,争取在短短的三个月内提高学生的听、说、读、写能力,发展学生的综合语言运用能力;面向全体学生,为学生全面发展奠定基础,为今后的进一步学习作好充分准备。
二、复习策略
1、系统归纳,分清脉络。依纲扣本,注重双基,夯实基础(词汇,语法,句型),帮助学生学会复习,学会考试。
2、以学生为主体,坚持讲练结合的教学模式。并注重感情投资,利用学生的心理优势,多关注,多表扬,树立学生的自信心。
3、针对性复习。向优、良、中、差各层次学生搜集、积累他们平时在各方面出现的错误,对症下药,逐题突破。要求学生熟练地掌握中考中的每一种题型的命题意图。对听力部分、单项选择、完形填空、阅读理解、书面表达等各种题型进行强化训练。
三、情况分析
人教版英语共有五本书,七年级上下册和八年级上册比较简单,主要是词汇量的积累,简单的口语表达,八年级下册,九年级着重是语法,阅读。指导丛书中要求,在语言知识方面,学生学会使用四会单词和习惯用语或固定搭配;在听力技能方面,能听懂有关日常生活中的`熟悉的话题;在阅读技能方面,能阅读各种体裁和题材的简短的书面材料;在写作技能方面,能使用所学语言基础知识,以语篇为单位,清楚,连贯地进行控制性和开放性写作;在口语技能方面,能使用所学的语音,语法和词汇等基础知识,以口头的形式清楚,流利地表达自己的意思。根据考试的内容和考试的难易度比例,合理安排复习时间和复习方法很有必要。
四、时间安排:
整个复习分三个阶段:
第一轮:时间:2.28———4.29内容:单元复习。
第二轮:时间:5.2———5.27内容:专项复习(听力,语法,词语运用,完型填空,阅读理解,情景对话,书面表达。)
第三轮:时间:5.30———6.21内容:模拟考试
五、资料
1、《中考课时计划》
2、《天利38套历年真题》
3、初三全体英语教师集体编排的《中考课时计划》
六、复习内容与要求
从近三年的中考试题来看,年年有变化,但不是很大,总之,其试题容量大,覆盖面广,要求越来越高,越来越灵活,不仅加强了对英语基础知识的考查,更突出了对运用知识的能力的考查。我采用“三轮复习法”要求先全面学习,后进行重点复习和适应性考试复习,做到着眼全面,突出重点,点面结合,把全面复习和重点复习有机的结合起来,这样既系统全面又有所侧重,能使学生较好地掌握所学知识,考出优异的成绩。
九年级下册英语第十单元知识点总结归纳
英语最早被中世纪的英国使用,并因其广阔的殖民地而成为世界使用面积最广的语言。那么九年级下册英语知识点怎么学习呢?以下是小编准备的一些九年级下册英语第十单元知识点,仅供参考。
本学期,我将担任九年级四班的英语教学工作,作为一直从事中学英语教学的我,虽了解到了一些教学教法,但在实际的教育教学中中,我深深感觉到教中学英语之难之累,为了能在以后的工作中取得更好的成绩,特做计划如下
一继续认真学习永威的教学理念,积极运用“先学后教,当堂训练”的教学模式。
“先学后教,当堂训练”是蔡林森经过二十多年实践探索而创立的一种教学模式。假期我再一次仔细研读了介绍这种教学模式的材料,领会了这种模式每一节课主要有三个环节:“先学”“后教”“当堂训练”。三个环节要环环紧扣。而且目标的确定要切实可行,课上必须能够完成。另外自学指导要有效,就必须明确时间,内容,学习方法,达到的标准,考核的方法及要求。后教并不都是老师讲但老师讲是有必要的,教师讲的内容都是学生不会的,急需要讲的。且要做到精讲并讲透。本学期经过认真学习,整个教学模式成竹在胸所以运用起来比上学期会更得心应手多了。
二学习蔡林森教学理念,将认真实行“四清”管理。
本学期,我将继续实行四清管理,面对全体学生,重点是差生。每天自习辅导课,我帮助并清堂清为过关的学生。每周学生自查,互查后,我们几个同年级同学科的老师带将领课代表班与班对查,并填写周清登记表。另外运用四清,培养优秀生和尖子生,为中考打下坚实的基础三按照“考改考”的模式认真上好每一节复习课。
首先,老师精心设计好检测题,测试后马上出示答案并了解学情,发现问题,针对问题让学生们更正讨论,学生确实不会的老师要讲清讲透,然后组织学生背记且检查,下一节课又做同类测试题,使学生能够牢固且熟练地掌握所学知识和典型习题。更多的培养优秀生四认真研究教学大纲和历年中考试题,把握好中考方向。
认真研究近两年的中考试题,狠抓中考重点,把握中考方向,有的放矢的进行备战中考的练习。同时注重培养学生学习及运用知识的能力和应考技巧。从而是学生能够从容应对中考的考验。
下学期的计划和努力方向。
本学期一定要积极运用“先学后教,当堂训练”的教学模式,学习蔡林森没有教不好的学生教学理念。熟练掌握“先学后教,当堂训练”的教学方法,从学情出发,积极改革创新,提高课堂教学效率,提高个人素质。通过“四清”管理打牢基础,提高学生素质,争取在明年中考取的优异的成绩。
人教版九年级下册英语第十一单元知识点总结归纳
与英语为母语的人相比,将其作为第二语言学习的人更多。那么关于九年级下册英语怎么学习呢?以下是小编准备的一些人教版九年级下册英语第十一单元知识点,仅供参考。
笔试部分(85分)
I.选择题(20分)
i.词语释义(共5小题,每小题1分)
从下面每小题的A、B、C、D四个选项中选出可以替换划线部分的佳选项。
( ) 1. The old man wears a set of false teeth when he eats.
A. white B. wrong C. strong D. not real
( ) 2. Be sure to give your family my regards.
A. letters B. photos C. greetings D. gifts
( ) 3. If you buy ten bottles, the price of each bottle will come down to 5 yuan.
A. show B. fall C. rest D. lie
( ) 4. When the boy got his favourite bike, he was on top of the world.
A. very hungry B. very satisfied
C. very angry D. very disappointed
( ) 5. Keep an eye on my purse - I'm just going to the bathroom.
A. Look through B. Look up
C. Look after D. Look out
ii选择填空 (共15小题 , 每小题 1分 )
从下面每小题的 A、B、C、D四个选项中选出佳答案。
( ) 6. ---- Could you play ________ basketball when you were a primary school student?
---- No, I couldn't, but I could play ________ violin.
A. the; an B. /; the
C. a, an D. the; /
( ) 7. ---- You ________ unhappy today, Jane.
---- Yes. My father ________ me to go to the zoo, but he ate his words.
A. watch; spoke B. think; thanked
C. are; sighed D. look; promised
( ) 8. ---- If you want to have a hot bath, you should pay ________ money.
---- You mean the fee of hot baths is not ________ in the hotel price?
A. extra; impressed B. more; rested
C. extra; included D. more; including
( ) 9. ---- I don't ________ playing football.
---- Really? So what are you ________ in?
A. like; interested B. like; tasted
C. prefer; excited D. prefer; surprised
( ) 10. ---- ________ is the pair of trainer shoes?
---- It ________ me 200 yuan.
A. How long; took B. How much; cost
C. How often; spent D. How many; paid
( ) 11. ---- Are you ________?
---- Sorry, I am ________. Could you please give me five more minutes?
A. free; surprised B. fine; OK
C. busy; ready D. ready; unprepared
( ) 12. ---- What's your plan for your holiday?
---- It ________ the weather! If ________ doesn't rain, I will go climbing.
A. depends on; it B. looks on; it
C. relies on; she D. tries on; she
( ) 13. ---- Have you ________ Tim to go with us'?
---- No. He wants to but he ________ care for his sister because his parents are busy.
A. regretted; should B. persuaded; has to
C. contacted, likes to D. introduced; needs to
( ) 14. ---- I ________ your advice very much.
---- You are welcome. I hope it is ________ to you.
A. like; unhelpful B. raise; unhopeful
C. appreciate; helpful D. thank; hopeful
( ) 15. ---- Hello, waiter. We didn't ________ any noodles, but there is a bowl of noodles on the _______.
---- Sorry, it is my error.
A. order; bill B. take; paper
C. produce; brain D. rent; book
( ) 16. ---- ________ it is late, I shall go home now.
---- OK, go ________.
A. So; down B. If; up
C. Since; ahead D. Because; out
( ) 17. ---- What did the man say to you?
---- He ________ me where the post office ________.
A. tells; is B. asks; is
C. said; was D. asked; was
( ) 18. ---- What ________ is a basketball?
---- It is ________.
A. shape; round B. height; oval
C. weight; heart-shaped D. shape; square
( ) 19. ---- What did Jack eat?
---- He ________ an apple before he ________!
A. ate; sleeps B. had eaten; slept
C. eats; was sleeping D. has eaten; slept
( ) 20. ---- Dan hurt his leg when he was playing football.
---- ________
A. I'm not sure about it! B. No, I don't believe it!
C. I am sorry to hear that. D. Oh, my God!
II.完形填空(10分)
阅读下面的短文,从短文后所给的A、B、C、D四个选项中,选出能填入相应空白处的佳选项。(共10小题,每小题1分)
At the beginning of the world, it was Bear who owned Fire. Bear and his people carried Fire with them ____21____ they went.
One day, Bear and his people came to a great forest, where they found many acorns(橡子) ____22____ on the forest floor. Bear set Fire at the edge(边缘) of the forest, and he and his ____23____ began eating acorns. They went further and further away from Fire, eating the delicious acorns and looking for____24____.
Fire blazed (发出火焰) up happily for a while ____25____ it had burned almost all of its wood. It started to smoke. "___26____ me! Feed me!" Fire shouted to Bear. But Bear and his people did not hear Fire's ____27____.
At that moment, Man came walking through the forest and saw the small Fire.
"What should I feed you?" Man asked, He had____28____ seen Fire before.
"I eat sticks and wood of all kinds," Fire said.
Man ____29____ a stick and put it on Fire. Man got a second stick and then a third one... By this time, Fire's hunger was satisfied.
Man warmed himself by the Fire, enjoying the changed colors. Man and Fire were very happy together, and Man fed Fire sticks whenever it got hungry. And now Fire ____30____ to Man.
( ) 21. A. whatever B. however C. wherever D. whenever
( ) 22. A. blessing B. playing C. sleeping D. lying
( ) 23. A. people B. sister C. brother D. parents
( ) 24. A. less B. more C. little D. few
( ) 25. A. until B. unless C. if D. but
( ) 26. A. Hire B. Twist C. Feed D. Mend
( ) 27. A. education B. step C. voice D. cries
( ) 28. A. ever B. never C. always D. often
( ) 29. A. picked up B. took up C. looked up D. put up
( ) 30. A. lowers B. cheers C. likes D. belongs
III. 阅读理解(共35分)
i.阅读下列短文,从下面每小题的A、B、C、D四个选项中选择佳选项。(共25小题,每小题1分)
A
Teaching English as a foreign language is very popular for many travellers. In March I started teaching English in Thailand.
I really love teaching. I knew it could be a lot of fun, especially with my students who are 3-5 years old. But I had no idea just how much I would actually enjoy it. The only reason I started was simple - it was an easy way to make money.
I had no idea Thai children could speak English so well at such a young age. My children could describe colours, shapes, body parts, days of the week and classroom objects!
Two things changed after working. The first one was in the first weeks of teaching, I liked to have my lessons planned out, but things didn't go as expected. Now I am happy to walk into a classroom with whatever I need for the subject.
I guess the other thing would be how much the children trust me. 18 weeks ago these children were unconfident and pretty shy, but now they can't wait to get involved.
In 6 months I have no idea where I will be, but right now I love teaching and enjoy working with the kids every day. Will I teach again - I'd like to think so!
( ) 31. Where is the writer most probably from?
A. Korea. B. England.
C. China. D. Japan.
( ) 32. Which of the following is NOT the writer's student?
A. May, 4 and a half, who can tell different shapes.
B. Wilton, 3, who can tell different colors.
C. Nick, 5, who can count from one to one hundred.
D. Leonie, 6, who is good at English grammar.
( ) 33. Which of the following is TRUE?
A. The writer might be short of money when he traveled in Thailand.
B. All the children in the writer's class are very naughty.
C. The writer will never be a teacher again.
D. The writer never has classes in the classroom.
( ) 34. What is the meaning of the underlined word "unconfident" in Chinese?
A. 粗心大意的 B. 缺乏信心的
C. 不切实际的 D. 骄傲自满的
( ) 35. What is best title for the passage?
A. Teaching is a good job.
B. How clever the Thailand children are!
C. My travel experience in Thailand.
D. First time as an English teacher in Thailand.
B
The city of Cannes is situated in the southern part of France, in the Riviera region and has a population of nearly 70,000. Cannes is very famous around the world for its Film Festival and also for its Cannes Lions Festival. It is a comfortable city and has tourism (旅游业) as its main industry. Cannes offers some of France's finest hotels. You can surf the Internet for more information about hotels.
It is 905 km away from Paris, 164 km from Marseille and 26 km away from Nice. The coast is often visited. The Boulevard de la Croisette is one of the most important attractions for people who love the beach, sun and sand.
La Croisette is a 12 km waterfront avenue (海滨林荫道) with many trees, hotels, cafes, shops and restaurants around. Visiting the Musee de la Castre is also a good choice for seeing beautiful works of art, paintings and so on. And if you want to relax,
you can visit the ?les de Lérins (Lé rins Islands) with nice views and beautiful beaches.
If you just take a walk in the streets of Cannes, you will discover a very friendly atmosphere (气氛). The main streets are d'Antibes and Meynardier. You will have a good time in the shops. Its restaurants are very good, although the prices are sometimes expensive. Depending on whether the restaurant is located on the waterfront or not, the price will be a bit more expensive.
( ) 36. What do the underlined words "is situated" mean?
A. Directs. B. Identities.
C. Lays. D. Lies.
( ) 37. What does the underlined word "It" refers to?
A. Marseille. B. Nice.
C. Cannes. D. France.
( ) 38. To see beautiful works of art and paintings, you can visit _________.
A. Lérins Islands B. the Musée de la Castre
C. the Boulevard de la Croisette D. Marseille
( ) 39. The price of restaurant would be more expensive if it is located _________ according to the fourth paragraph.
A. on the water Front B. in d'Antibcs
C. in Meynardier D. in Cannes
( ) 40. According to the passage we can know that the passage is about _________ in France.
A. fashion B. places
C. people D. sports
C
On my first holiday in America, I went to a large supermarket to buy breakfast. And although this was an English-speaking country that I knew well through films and TV, I was amazed. Everything came in unfamiliar (不熟悉的) packaging (包装),with things I'd never heard of, Even things as simple as corn chips were strange, in different colours including black and purple.
Tilse, who works for Nutrition Australia, first realized there was a problem six years ago. After teachers at her children's school quietly shared their opinions about the diets, she knew something about it. "They cared for what many children were bringing to school for lunch," she said. "Mostly packaged foods, such as chips are not healthy."
Tilse said, “They've managed to escape war areas and get to Australia, only to face the very real risk of running into heart disease. All because they're making wrong choices about food."
"Before I came to Australia, I'd never seen a sandwich," said Joseline Ntunzusenimanima, a 33-year-old mother of seven from Burundi in East Africa. "There were so many fruits I had either never seen or not been able to buy for many years. I was in shock for the first four days after I arrived. I didn't know what to do or where to go because I was just amazed to see plenty of food, peace and safety."
( ) 41. What did the writer feel about the food when she visited the USA for the first time?
A. Happy. B. Excited.
C. Amazed. D. Comfortable.
( ) 42. Tilse thinks that most packaged foods in Australia are _________. A. interesting and cheap B. good for children's health
C. strange and expensive D. bad for children's health
( ) 43. How many children are there in Joseline Ntunzusenimanima's home?
A. Six. B. Seven.
C. Eight. D. Nine.
( ) 44. We can most probably read the passage in a magazine about _________.
A. music B. news
C. food D. education
( ) 45. What is the best title for the passage?
A. Wrong choice about food. B. Have a big breakfast.
C. How to choose food. D. What to bring to school.
D
Disneyland Paris
Disneyland Paris was set up as Euro Disney in 1992. The company changed the name in 1995. Like Tokyo Disney, it has two separate parks. The main park bas live different lands -Adventure-land, Fantasyland, Discovery land, Frontierland and Main Street USA. The second park, Walt Disney Studios Park, revolves(环绕) around a movie theme and offers surprising and special shows. Disneyland Paris also contains seven Disney hotels and a pair of golf (高尔夫) courses: one for adults and one for children.
Telephone: 011-33-1-60-30-60-30
Website: http//www.disneylandparis.com
Hong Kong Disneyland
Hong Kong Disneyland debuted(首次亮相) in 2005 and still contains just one theme park. It holds four theme lands like other Disneyland parks - Main Street, Fantasyland, Adventureland and Tomorrowland - with three more lands scheduled(预定的) for opening between 2011 and 2014. Besides the theme park, Disney also runs a pair of official hotels and builds a man-made lake.
Telephone: 011-852-1-830-830
Website: http//www.park.hongkongdisneyland.com
( ) 46. If Jim goes to Disneyland Paris, he can't ___________.
A. see films B. play golf
C. live in a Disney hotel D. go boating on the lake
( ) 47. There will be ___________lands in Hong Kong Disneyland in 2015.
A. six B. seven
C. eight D. four
( ) 48. We can know the ___________about the two parks according to the passsage.
a. telephone numbers b. websites
c. addresses d. ticket price
A. a & b B. a & d
C. a & c D. c & d
( ) 49. Which of the following is TRUE?
A. Tokyo Disney has two separate parks.
B. All the Disney parks have two separate parks.
C. Disneyland Paris is the best one in the world.
D. Hong Kong Disneyland has five different lands nowadays.
( ) 50. The writer wrote the passage to ___________.
A. tell us the best time to visit Disneyland
B. tell us Hong Kong Disneyland is better than anyone else
C. ask us to visit the Disneyland
D. introduce these two Disneylands
E
The United States is suffering its worst drought (干旱) in almost sixty years. The National Climatic Data Center also says high temperatures in June added to the warmest twelve-month period on record. Record-keeping began in 1895. The drought
map showed that conditions improved in the Southeast in June compared to May. But the drought is expected to continue in large parts of the country. Last week, Agriculture Secretary Tom Vilsack met with President Obama. Mr Vilsack says the drought has seriously influenced some crops, such as corn and soybeans (大豆). And the United States is the world's leading producer.
The drought has made prices of com and soybeans increase. Both of them are used in food production and for animal feed. Last week the United Nations Food and Agriculture Organization reported that corn and wheat prices increased by 20% over the past three weeks.
In the United States, farmers may quickly reduce the size of their animals rather than pay higher feed prices to keep them. That increased supply of meat would reduce meat prices in the short term. But those prices could increase in several months.
Mr Vilsack says the effect of the drought is hard to predict(预测). Some areas are getting rain, and drought-resistant (抗旱的) seeds have helped crops grow well in some areas.
( ) 51. We can know the drought record of the USA has been kept for ________
years of the USA up to now.
A. 97 B. 207
C. 221 D. 117
( ) 52. Which of the following American presidents met with Tom Vilsack?
A. George Washington. B. Abraham lincon.
C. George Bush. D. Barack Obama.
( ) 53. If the price of a kilo of corn was 3 dollars last December, how much is a kilo of corn now?
A. 2.4 dollars. B. 3 dollars.
C. 3.6 dollars. D. 3.9 dollars.
( ) 54. Why is the meat price lower than before?
A. Because there are more and more animals.
B. Because farmers kill them to save their food.
C. Because people don't like eating meat now.
D. Because the government (政府) asks the
( ) 55. What is the best title for the passage?
A. US faces the worst drought in almost sixty years.
B. Take action to help the USA.
C. What does the country do in the drought areas?
D. President Obama meets with Agriculture Secretary.
ii.选择下列词汇完成下面对话。(共5小题,每小题1分)
A. much B. already C. since
D. looks E. one F. way
A: Can I help you?
B: Yes. I want to buy a skirt.
A: This (56) ___________ please. All our skirts are in this section. How do you like the red one here?
B: It looks nice, but I don't like red. It (57) ___________ very hot.
A: Do you like white? There is also a white (58) ___________.
B: I think that's what I want. How (59) ___________ is it?
A: It's sixty-six yuan.
B: How about fifty yuan?
A: Hmm, (60) ___________ you like it so much, you can take it with fifty-five yuan. That's the lowest price I can offer.
B: That's good! I'll take it.
ⅲ. 选择下列句子完成下面对话,有两顶多余。
A. I just wonder what will happen in the future.
B. I am afraid I can't agree with you.
C. Maybe I need to change my plan.
D. It was not so good as l had expected.
E. But I think history is interesting.
F. It was more interesting than I had expected.
G. He made the class lively.
A: What do you think of yesterday's history class, David?
B: (61) ___________
A: Why? It is said that Mr Smith is a good teacher.
B: He talked too much.
A: That's why I like him. (62) ___________ Besides, history is interesting itself.
B: I'm not interested in history because all the things happened in the past. (63) ___________
A: (64) ___________ It tells us something about our ancients(祖先).
B: (65) ___________
IV.词汇(10分)
用所给词汇的适当形式填空。(共10小题,每小题1分)
66. Susan's parents were ___________ (disappoint) when they knew Susan failed the exam.
67. If I forget my father's birthday, please ___________ (remind) me.
68. "Don't cry, baby!" the father said ___________ (gentle) to the girl.
69. You went in the wrong ___________ (direct), sir.
70. I am afraid that you are ___________ (cheat) by the little boy.
71. Mr Smith got a good ___________ (educate) when he was young.
72. I plan to give a ___________ (surprised) to my son on his thirteenth birthday party.
73. The kindergarten teacher ___________ (clap) to attract the children's attention.
74. The population of his hometown has greatly __________ (increase).
75. I want you both to be on your best ___________ (behave) at Grandma's.
V.书面表达(10分)
日前,深圳市交警局发出通告,除了快餐、电信抢修等部分特殊行业用车外,个人电动车将被禁止在深圳规定路段行驶。对于“限电令”,大家的意见各不相同:不赞成者认为电动车给人带来很多方便,它便捷、便宜、环保;赞成者认为电动车扰乱交通秩序,而且危险。你的想法是什么?请你就此写一篇作文。
要求:
(1)条理清楚,意思连贯,语句通顺,标点正确;
(2) 80词左右,开头已给出,不计入总词数。可适当发挥,以使行文连贯。
Shenzhen City Police Bureau announced that personal electrical bikes would be forbidden. Different people have different ideas.
化学是一门研究物质性质、结构、构成、变化及其与能量的关系的科学。下面是小编为大家带来的人教版初三下册化学第九单元知识点总结,希望大家能够喜欢!
一、溶液的形成
1、溶液
溶液概念:一种或几种物质分散到另一种物质里面形成的混合物。
溶液特征:均一性、稳定性。
注意:a、溶液不一定无色。
b、溶质可以是固体、液体或气体,水是最常见的溶剂。
c、溶液的质量等于溶质的质量加溶剂的质量,但溶液的体积不等于溶质的体积加溶剂的体积。
2、判断溶质和溶剂
3、饱和溶液、不饱和溶液
(1)概念
(2)判断方法:继续加入溶质,看能否溶解。
(3)饱和溶液和不饱和溶液的转化方法:加溶质、蒸发溶剂。
(4)浓、稀溶液与饱和不饱和溶液的关系
①饱和溶液不一定是浓溶液。
②不饱和溶液不一定是稀溶液。
③一定温度,同一种溶质的饱和溶液比不饱和溶液浓。
(5)溶解时放热、吸热现象
二、溶解度
1、固体的溶解度
定义:一定温度下,固态物质在100g溶剂中达到饱和状态时所溶解的质量。
四要素:①条件:一定温度②标准:100g溶剂③状态:达到饱和④质量:溶解度的单位是克。
(1)溶解度的含义。
(2)影响固体溶解度的因素:①溶质、溶剂的性质和种类;②温度。
(3)溶解度曲线
2、气体溶解度
(1)定义:压强为101kPa和一定温度时,气体溶解在1体积水里达到饱和状态时的气体体积。
(2)影响因素:①气体的性质;②温度;③压强。
3、混合物的分离
(1)过滤法:可以用来分离可溶物和难溶物
(2)结晶法:可以用来分离几种可溶性物质