Malaysia Negara Maju

Malaysia sedang berada di ambang negara maju. Untuk tempoh lapan tahun dari sekarang, negara kita akan melalui satu fasa transformasi penting yang akan menentukan samada kita berjaya melangkah ke gerbang negara maju apabila fajar tahun 2020 menyinsing.

TRANSFORMASI PENDIDIKAN NEGARA

Dalam era transformasi ini, seluruh minda dan kudrat rakyat perlu digembleng untuk memacu kemajuan negara dalam persekitaran global yang lebih mencabar.

Pendidikan Yang Berkualiti dan Inovasi

Pelaksanaan empat inisiatif di bawah Bidang Keberhasilan Utama Negara (NKRA) bagi sektor pendidikan, yang bertujuan untuk memperluas akses kepada pendidikan yang berkualiti dan berkemampuan

Modal Insan Yang Berpengetahuan

guru inovasi yang mempunyai kebolehan untuk melengkapkan murid dengan kemahiran alaf baru seperti keupayaan berfikir secara kritis, kebijaksanaan menyelesaikan masalah dan daya kreativiti yang tinggi.

Terima Kasih Guru

Berkat sentuhan para gurulah, lahirnya insan-insan yang terdidik dengan ilmu dan adab, yang kini berada di setiap lapangan ekonomi, sosial, budaya, pendidikan dan sebagainya untuk menggerakkan kemajuan bangsa dan nusa. Kejayaan negara kita beralih daripada sebuah negara berasaskan ekonomi pertanian kepada sebuah negara perindustrian baru yang pesat berkembang, sebahagian besarnya adalah kerana jasa dan bakti para guru.

Thursday, May 31, 2012


[Science Form 3] About Blood

The transport system in humans is called the circulatory system, which is made up of heart and blood vessels.

The functions of the blood circulatory system are to:
  • supply oxygen to all body cells and eliminate carbon dioxide,
  • transport waste products

Structure of the heart

Oxygen-rich blood (red color)
Oxygen-poor blood (blue color)
  • AO = Aorta
  • LA = Left atrium
  • LV = Left ventricle
  • PA = Pulmonary artery
  • RA = Right atrium
  • RV = Right ventricle

The heart is a muscular structure that contracts in a rhythmic pattern to pump blood. It si the size of your fist and has four chambers:
  • right atrium
  • right ventricle
  • left atrium
  • left ventricle

The space in the atrium is smaller than that in the ventricle. The wall of the ventricle is thicker and stronger than that of the atrium.

Valve TRICUSPID - Prevents blood in the right ventricle from flowing back to the right atrium.

Valve BICUSPID - Prevents blood leaving the heart from flowing back.

Wednesday, May 30, 2012

TEKNIK-TEKNIK MENJAWAB SOALAN PEMAHAMAN B.CINA SPM 2012



现代文阅读理解


近年来,“现代文理解”在大马教育文凭华文试卷二所占的“地位”日趋重要,越来越具挑战性,对学生的阅读能力要求也越来越高。许多考生在现代文理解一环答不到点上,这反映出学生阅读能力发展的不全面。因此,考生们应在这方面加强本身的阅读与理解能力。

现代文阅读理解训练是一个长期积累的过程,它的提高需要学生进行相关知识与技巧的积累,需要一篇又一篇地阅读文章,需要一次又一次地进行练习。只有通过持之以恒的积累,阅读解题能力才有可能进入游刃有余的境界。

考生在阅读篇章时,要尽量要求自己能做到以下几点:

1 能理清文章的思路;
2 能初步领悟作品的内涵;
3 能从中获得对自然、社会、人生的有益启示;
4 能品味作品中富有表现力的语言;
5 能联系文化背景对作品的思想感情作出自己的评价;
6 能对作品中感人的情景和形象说出自己的体验;
7 了解作品几种常用的描写方法及其作用。


一、如何整体感知文章?

“整体感知”是指在阅读的过程中将一篇文章看作一个不可分割的整体,通读全篇,观其大略,对材料所承载的主要意思、作品的结构特征、作者的情感态度和文章的写作意图做到完整认知、全面把握。

在进行文章的整体感知时,一般可以从以下几方面进行:
1. 感知文章基本内容
a. 浏览标题,领悟基本内容。
b. 通读全文,把握材料的要义,了解文章的基本内容。
i. 如果是以写人为主的记叙文,要弄清楚文中写了哪些人,其中主要人物是谁,围绕主要人物选取了哪些事件来写,哪些事件详写,哪些事件略写等。
ii. 如果是以叙事为主的记叙文,要抓住记叙的线索和要素,弄清事情发生发展的过程,明确文中重点叙述的是事件的哪一过程。
iii. 如果是写景状物类的记叙文,则要弄清文中写了哪些景、物,着重描绘景、物的哪些方面,分别抓住它们的什么特点来写的等等。

2. 感知文章思路结构

3. 感知文章中心主旨



一天早上,我决定尝试一种经历。我戴上眼罩,眼睛完全看不到东西,跌跌撞撞地走进屋子。我试着完成失明状态下最简单的任务:
我想喝水,却将水龙头对准自己的衣袖。
我走到冰箱前拿果冻。结果我弄出来的是花生三明治味道怪怪的。
我想看书,却看不见。
我想看电视剧,结果既看不到图像,也无法跟上剧情。
我想将一张唱片放到唱机上,却分不清我想要的唱片是哪张。
最后,我坐在起居室中央的地板上感到非常沮丧。从那天早上过后,我再也没有像从前那样看待残疾人。
有一天,我想小睡一会儿,但孩子已在我床上睡着了。我不想吵醒他,于是我在他的床上躺下。真是糟糕透了!我翻来覆去,无论采取何种睡姿,床上的弹簧和床垫老是抵着我的背脊令我无法安睡。小孩平时总是抱怨他的床,但他的麻烦一直未得到解决。现在这个问题摆在我面前,我一下子明白了。 ([美]柯特•汉克思《穿着别人的鞋子走路》)

思考 作者在文中写了哪几件事?(用简洁的语言概括)?写这些事的用意是什么?

解答


说明
 我们运用归纳法可以概括第一件事的主要内容:戴上眼罩喝水、拿东西、看书、看电视、听音乐,这是对盲人生活的尝试,结果因为诸事不便,心中非常沮丧;
 通过梳理记叙的要素可以概括第二件事的内容:事情的起因——孩子睡了“我”的床,“我”无处可睡,经过——“我”睡在孩子的床上,结果——无法入睡,因此可以简单地概括为“睡孩子的床无法安睡”。
 对于作者的写作目的,可以通过看标题和分析文章内容的方法来把握。这篇文章的题目《穿着别人的鞋子走路》以比喻的形式形象地告诉人们,要站在别人的角度来考虑问题;而文中所记叙的两件事都是处在别人位置上的感受,也说明了这个道理。

二、如何把握文章的主旨?

所谓主旨,是指作者写作的意图、目的。它是阅读文章的重点所在。理解文章的主旨一般有以下方法:
1. 分析文章标题
2. 分析文中的议论抒情句

例1
……人生最有意义的事将会对我们产生恒久的影响,会成为我们一生中一直闪亮的灯塔,会影响到我们人生的航线和生命的质量。
我常常在想,生命里最有意义的事,往往就静默于你的生命之中,然而却会在你生命的某一时刻,呈现出强烈的意义来。
那是一年夏天的事。…… (《夏日原野上的追赶》节选)

这里节选的是文章的开头,它以精辟的议论开宗明义地告诉读者:人生最有意义的事情“会对我们产生恒久的影响”,“会影响到我们人生的航线和生命的质量”。

3. 抓住文中人物的重要语言去分析
4. 分析文中含义深刻的句子
5. 运用归纳法概括文章的主旨

我只在故乡呆了六年,以后就离乡背井,漂泊天涯。在济南住了十多年,在北京度过四年,又回到济南呆了一年,然后到欧洲住了近十一年,重又回到北京,到现在已经四十多年了。在这期间,我曾到过世界将近三十个国家,我看过许许多多的月亮。在风光旖旎的瑞士莱茫湖上,在平沙无垠的非洲大沙漠中,在碧波万顷的大海中,在巍峨雄奇的高山上,我都看到过月亮,这些月亮应该说都是美妙绝伦的,我都异常喜欢。但是,看到它们,我立刻就想到我故乡那苇坑上面和水中的那个小月亮。对比之下,无论如何我也感到,这些广阔世界的大月亮,万万比不上我那心爱的小月亮。不管我离开我的故乡多少万里,我的心立刻就飞来了。我的小月亮,我永远忘不掉你! (《月是故乡明》节选)

思考 作者描写世界各地美妙绝伦的月亮,其用意是什么?

解答

说明
 无论是在风光旖旎的瑞士莱茫湖上、平沙无垠的非洲大沙漠中,还是在碧波万顷的大海中、巍峨雄奇的高山上,作者所见到的月亮,都比不上在家乡所看到的月亮,它们无时无刻不勾起作者对家乡那轮月亮的思念。因此,写世界各地的月亮,目的是为了和故乡的月亮形成对比,突出作者对故乡的思念之情。


三、如何理解词语在具体语境中的含义和作用?

词语是构成文章的基本单位,理解词语在文中的含义是阅读文章的基础,我们可以通过以下方法把握词语在具体语境中的含义:

1. 理解多义词的选项。
有时,遇到多义词,要结合上下文,借助工具书,弄清词语用的是它的本义还是引申义,亦或是比喻义。

例1 剩下的生命越是短暂,我愈要使之过得丰盈充实。 (《热爱生命》)
 “丰盈”一次有两个含义:一指身体丰满,二指富裕。从文中看,形容生命的价值,应该选用“丰富”这一词义。

例2 这朦胧的橘红的光,实在照不了多远,但这小姑娘的镇定、勇敢、乐观的精
神鼓舞了我,我似乎觉得眼前有无限光明。 (《小橘灯》)
 “朦胧”的两个词义分别是“月光不明”和“不清楚,模糊”,在文中,用来形容小橘灯的光,很明显应该用后一个词义。
例3 天使的声音在耳边吹拂,这是老师的吗?我怔了一下,缓过神,这“批评”
是对着我的吗?怎么闻不到硝烟味?
 “硝烟味”在这里运用的是比喻义,指老师语气的严厉或大声的批评、呵斥。

2. 揣摩词语的指代义或概括义。
记叙文中有些词语具有一定的指代意义,往往用来指代文中的一些人、事、物、景,其指代的对象一般出现在前文中。我们可以从上文中由近及远地寻找,理解其含义;有些词语概括能力很强,往往提示或总结某些内容,理解时候要结合上下文的有关内容,正确理解它的概括义。

例4 对于叔叔回国这桩十拿九稳的事,大家还议定了上千种计划。甚至计划到要用这 位叔叔的钱置一所别墅。我不敢肯定父亲对于这个计划是不是进行了商谈。 (《我的叔叔于勒》)
 文中的代词“这个”指的就是前文提到的用叔叔的钱置一所别墅的计划。


3. 揣摩词语的特殊含义。
特殊含义是指词语在特殊的语境中所具有的临时性含义。

例5 鸟儿将巢安在繁华嫩叶当中,高兴起来了,呼朋引伴地卖弄清脆的喉咙,唱出宛转的曲子,跟清风流水应和着。 (《春》)
 “卖弄”的本义是有意地显示自己的本事,带有贬义色彩,但文中指鸟鸣的清脆悦耳,烘托出春天和悦的气氛。

例6 我希望他们不再像我,又大家隔膜起来……然而我又不愿意他们因为要一气,都如我的辛苦碾转而生活,也不愿意他们都如闰土的辛苦麻木而生活,也不愿意都如别人的辛苦恣睢而生活。 (《故乡》)
 文中的三个“辛苦”因为指代的对象不同,就有了不同的含义。第一个“辛苦”指如“我”一样的奔波劳碌;第二个“辛苦”指如闰土一样的辛勤劳苦;第三个则指如官绅一类人的生活,他们行为放纵而凶暴,胡作非为。

4. 理解词语的深层意义。
有时,对词语的理解不能从字面分析。要注意联系上下文乃至全文的内容,联系全文的主旨和作品的写作背景去理解,从中窥见词语的深刻含义。

例7 我到现在终于没有见——大约孔乙己的确死了。 (《故乡》)

 文中“大约”和“的确”看似矛盾,其实隐含深意:从前文所叙述的情节并不能断定孔乙己一定是死了,所以说是“大约”,但是,联系孔乙己生活的时代背景,联系作者的写作意图去理解,作为失去谋生能力的孔乙己,“死”是其必然的结局,所以说是“的确”。在轻描淡写之中,控诉了那个社会制度的恶罪。
例8 一踏进两行菜篮的中间,就总会感觉到菜篮的后面那一双双渴望的目光。……若是你摇摇头走开了,你背后的目光便暗淡下来。 (《买菜的心情》)

 “暗淡”一词形象地表现了卖菜人心中的失望。

我茫然无措地搜寻着来自它周围的威胁物。显然,我没有找到,只能任凭它像个不规则的亮点在远处的苍穹中变得越来越恍惚。正是在这种恍惚中,我下意识地瞅瞅我那照相器材:探出去的长镜头像枪口一样,正瞄准了这只无辜的小生灵。顿时,我明白了我的错误。它是担心,我按住快门的手会在瞬间发射出夺命的子弹。
(《镜头下逃命的藏羚羊》)

思考 根据文意,说说下面加点的词语“错误”的具体含义是什么?

解答


说明
 我们在理解“错误”这个词的含义时,一定要放在语境中去考察。
 从前文可以知道藏羚羊受到了威胁,而“我”在看到自己的照相器材时知道了它所受的威胁来自于“我”那形状像抢的长镜头,再结合语段的最后一句话就可以正确把握“错误”一词在文中的含义。

四、如何理解记叙文中重点句子的含义?

要理解文章中重点句子的含义,首先要弄清楚什么是“重点句子”,它一般指那些能够表现文章中心、突出人物性格特征、体现人物内在情感或其他具有深刻含义的语句。

1. 从关键词语入手理解句子含义。

例1 第二天,他在阳光温暖的抚触下,从极深的禅室里睁开眼睛,看到他披在小偷身上的外衣被整齐叠好,放在门口。阐师非常高兴,喃喃地说:“我终于送了他一轮明月!” (《送一轮明月》)

 要理解文中画线句子的含义,首先要从关键词“明月”入手,“明月”的特点是照亮黑暗,而小偷的心灵之地正缺少“明月”,这样,我们就可以理解这句话的意思:禅师以自己的行为感化了小偷,使他从黑暗的生活中走出,有了光明的人生。

2. 结合写作手法,体会句子深层的含义。
例2 过了一阵之后,作家又觉得未改行,原来创作同摆渡一样,目的都是把人渡到前面的彼岸去。 (《摆渡》)

 从句子所用的表现手法看,这句话运用了比喻的修辞手法,把作家的作用比作是渡工“摆渡”,我们抓住他们的共同点“由此岸到彼岸”即可理解这句话的含义:作家的作用在于用自己文章中的真情实感去感染读者,引导人们净化心灵,走向精神升华的彼岸。

3. 联系作者情感、作品主旨理解句子含义。
例3 这样,我们在阳光下,向着那菜花、桑树和鱼塘走去。到了一处,我蹲下来,背起了母亲,妻子也蹲下来,背起了儿子。我的母亲虽然高大,然而很瘦,自然不算重;儿子虽然很胖,毕竟幼小,自然也轻,但我和妻子都是慢慢地、稳稳地,走得很仔细,好像我背上的和她背上的加起来,就是整个世界。
(《散步》)

 “妻”的背上是儿子,“我”的背上有母亲,我们两人的背上,背负着的其实整个家庭的重担。从文章的写作意图来看,作者所要表现的不仅是中青年人对家庭的承前启后的重任,也表现他们的社会责任感。理解了这一点,便不难理解画线句子的含义:我们(中青年人)的背上承担着整个家庭和社会的重任。

我心里暗笑他的迂:他们只认得钱,托他们只是白托!而且我这样大年纪的人,难道还不能料理自己么?唉,我现在想想,那时真是太聪明了。 (《背影》)

思考 文中画线的句子有什么含义?

解答


说明
 要理解画线句子的含义,可以从理解词语“聪明”入手,文中所说的“聪明”,其实是事后反省自己时的自责之语,这里是反话,意思是责备自己当时“聪明过分”,其实是一点也不聪明。

五、如何欣赏作品中的形象?

作品中的形象主要指文章中的人物形象和写景状物类散文中的景、物等艺术形象。

每逢山溪水涨,他就守候在溪边,把他的学生一个一个背过小溪。惊悸的浊浪,滑溜溜的卵石,使他名声远播,某报撰文颂曰:《人桥》!
不久,他被提拔为文教班主任。
接替他的,是一个较小的姑娘。姑娘没有勇气涉过小溪,更谈不上背孩子渡水, 于是一到雨天黄昏,对岸就排着一支家长的队伍,一律裤腿高挽。
姑娘开始了奔波。她给文教办写信,向教育局长报告,跟家长争吵,掏出自己的工资带头集资……不久,小溪上架起了一座钢筋水泥结构的桥。孩子们可以顺顺畅畅上学了。
姑娘至今还在山村小学,教着四年级的50名学生。 《桥》

思考 小说《桥》中的两个人物做着帮学生过河的同一件事,但人物形象有没有差别?

解答


说明
 我们通过对小说故事情节的分析可以知道:前者背学生过河,显得陈旧落后,不能适应当今社会发展的新形势;后者想方设法在河上架起一座桥,具有开拓创新精神,能够顺应今天时代发展的需要。

下面就来谈谈欣赏的方法。

1. 欣赏文章中的人物形象。
(1) 把握人物形象的思想、性格特征。
i. 从情节入手,把握人物思想性格。作品中人物的思想性格是在情节发展之中表现出来的,并随着故事情节的发展逐步完善,所以要把人物放在一定的故事情节之中理解其思想性格。
半年后,公司又招聘了一批员工,总经理对新员工又交代了一次“不要走进那个没挂门牌的房间”。
这时,有个年轻人在下面小声嘀咕了一句:“为什么?”
总经理满脸严肃地答道:“不为什么?”
回到岗位上,那个年轻人还在不解地思考着总经理的吩咐,其他人便劝他只管干好自己的工作,别的不用瞎操心,听总经理的,没错。
年轻人却好奇地偏要刨根问底。众人便拿出公司的规章制度,提醒他别砸了手里让人羡慕的饭碗。
可年轻人偏偏来了犟脾气,非要走进那个房间看看。
他轻轻地扣门,没有反应,再轻轻一推,虚掩着的门开了。不大的房间里只摆了一张桌子,桌子上放着一个纸牌,而且沾满了灰尘,上面用红笔写着几个字——把纸牌送给总经理。
年轻人十分困惑地拿起那个已沾了许多灰尘的纸牌,走出房间。
这时,闻知年轻人闯入了那个禁止进去的房间,又拿出一个纸牌,有人开始为他担忧,有人替他出主意,劝他赶紧把纸牌送回去,大家同情地表示:一定替他保密,谁也不说他曾进入那个房间。
可年轻人却谢绝了众人的好意,乘电梯直奔15楼的总经理办公室。当他将那个纸牌交到总经理的手中时,总经理一脸笑意地宣布了一项让他震惊的结果——“从现在起,你被任命为销售部经理”。
…… (《虚掩着的门》)
说明:文章通过对年轻人走进了一间明令禁止进入的房间,并拿出一张纸牌交给总经理从而得到重用的情节,表现了年轻人不被条条框框束缚、勇于走进某种“禁区”,具有开拓进取精神的特点。

(2) 通过分析小说对人物的外貌、语言、动作、心理等方面的描写入手,把握人物思想性格。
丫姑野性,胆子比人的个儿还大;她把黑油油的大辫子七盘八绕在脖子上,雪白的牙齿咬着辫梢儿,光了脚丫子,双手合抱比她的腰还粗的树身,哧溜溜,哧溜溜,一直爬上树梢,岔开腿骑在树杈上。

说明:这段文字运用外貌和动作描写表现了丫姑的野性和胆大。

六、牛刀小试

一锅热汤热腾腾的窜出淡灰色的烟雾,便让人觉得幸福,表示年节到了,五十年代,只有年节,才有可能在桌子上摆放一锅上好的热锅,让人垂涎欲滴似的,等待开动。
爸爸上桌了,严肃地说了一声:“吃吧!”
孩子们飞快地把筷子斜斜插出,仿佛寻找隐伏于锅底的宝物,一筷接一筷,在青菜与豆腐铺底而成的火锅中,找寻细细小小的碎肉片,将它慢慢地放入口中,混着口液,眯着双眼,让细肉轻轻在口腔里滑动游移,悄悄地溜进食道,落入胃、肠之间。
一块肉,给人无比的幸福。
五十年代的幸福好简单,也好值得回味。 节选自游乾桂《谱写幸福的滋味》
1. “隐伏于锅底的宝物”指的是 ________________。

2. “将它慢慢地放入口中,混着口液,眯着双眼……”表示出的是
A 食不下咽的模样。
B狼吞虎咽,差点噎住的模样。
C慢慢品尝,舍不得吞下去的模样。
D食物太烫,没办法一口吞下去的模样。

3. “五十年代的幸福好简单”,意思是
A 当时的人心思单纯 B 当时的物价比较低廉
C 当时的人比较知足惜福 D 当时的人比较重视过年

答案: 1碎肉片 2 C 3 C

年轻的时候,总是紧紧跟随周遭的人群,急着向前走,急着想知道一切,急着要得到我应该可以得到的东西。却要到今天才能明白,我以为我争夺到手的也就是我拱手让出的,我以为我从此得到的其实就是我从此失去的。
但是,如果想改正和挽回这一切,却需要有更多和更大的勇气才行。人到中年,逐渐有了一种不同的价值观,原来认为很重要的事情竟然不再那么重要了,而一直被自己有意忽略了的种种却开始不断前来呼唤我,就像那草叶间的风声,那海洋起伏的呼吸,还有那夜里一地的月光。
多希望能够把脚步放慢,多希望能够回答大自然里所有美丽的生命的呼唤!
节选自席慕蓉《生命的滋味》
1. 第一段的意思是
A 时光易逝,青春不在。 C 得到了名利却迷失了心灵。
B 说明欲速不达的道理。 D 年轻时常随波逐流,缺乏主见。
2. 第二段“不同的价值观”,指的是心灵的
A 落叶归根 B 返璞归真
C 改邪归正 D 万境归空

3. 根据本文,下列何者不是“大自然美丽生命的呼唤”?
A 年轻的欢笑声
B 草叶间的风声
C 海洋起伏的呼吸
D 夜里一地的月光

答案:1 C 2 B 3 A


“雅舍”最宜月夜——地势较高,得月较先。看山头吐月,红盘乍涌,一霎间,清光四射,天空皎洁,四野无声,微闻犬吠,坐客无不悄然!舍前有两棵梨树,等到月升中天,清光丛树间筛洒而来,地上阴影斑斓,此时尤为幽绝。直到兴阑人散,归房就寝,月光仍逼近窗来,助我凄凉。 节选自梁实秋《雅舍小品》

1. 本文主要在描写雅舍的__________________。

2. “山头吐月,红盘乍涌”是形容_____________________。

3. 根据文中的描写,“地上阴影斑斓”,呈现出的是什么景象?
A天空乌云密布
B 水泼撒到地面上
C月光透过窗棂,照射到屋内
D月光透过树叶隙缝,照射在地面上

答案: 1月夜景象 2月亮渐渐从山边升起的样子 3 D

中国的文字实在奇妙,单单一个“忍”字,拆开来的意思就是心头一把刀,可见忍耐是一门多么艰难的功课。
在逆境中要忍耐,不要让不顺利的环境、失意的打击一再影响自己,只要坚持信心,继续努力,逆境也会化为顺境。
在贫寒中也要忍耐,贫寒不足以消磨一个人的志气,只有视贫寒为耻辱的人,才会陷自己于进退失据中。
失意中固然要忍耐,避免因为一时失意、他人的冷淡而愤世嫉俗,怨天尤人。
得意中固然要忍耐,人常得意忘形,骄傲自负,这时更应警惕,虚怀若谷,当能给自己营造一个更成功、更和谐的环境。
节选自杏林子《忍耐》

1. “在逆境中要忍耐,不要让不顺利的环境、失意的打击一再影响自己”,意思近于
A 出师未捷身先死,常使英雄泪满襟。 C 羌笛何须怨杨柳,春风不度玉门关。
B 不经一番寒彻骨,哪得梅花扑鼻香。 D 此情可待成追忆,只是当时已惘然。
2. 作者为什么认为“得意中更要忍耐”?

3. 根据你对“六书”的认识,“忍”字应该是
A 象形字 B指事字
C会意字 D 形声字

答案: 1 B 2过于骄傲容易导致失败 3 D

“静坐常思己过,闲谈莫论人非。”这句话虽然听来未免迂腐,可是,仔细想想,它却有很值得我们遵行的地方。
“静坐常思己过”,是一种反省的功夫。我们假如常能在静下来的时候,想到自己在做事或待人方面有疏忽有亏欠的地方,自然就减少了对人抱怨嫉恨或报复的心情;也同时由于明白了自己的过失而得到一些警惕,以后将不致再犯同样的过错。这是前人劝我们“静坐常思己过”的真正意义。
至于“闲谈莫论是非”则更是我们为人处世的一条金科玉律。
把谈论别人是非的精神用来“常思己过”,既可减少得罪人的机会,又可随时改正了自己的缺点,可以说是一举两得。
有人说:“假如我们都知道别人在背后怎样谈论我们的话,恐怕连一个朋友也没有了。”这并不是一句否定人与人之间友情的话,相反的,它正可以告诉我们,对背后的闲话尽可不必去认真打听和计较。
要知道,人们背后一时兴之所至,谈到了你的过错或缺点,说了对你不利的话,这是人之常情。即使他是你的朋友,偶尔一两次顺口说来的话,也并不证明他不够朋友。假如你不知道,这事情就会和根本没有发生过一样。
可是,假如你时常担心别人背后对你的谈论,而要千方百计地去打听的话,传话的人可能会把事情夸张些或歪曲些。这样一来,本是无意之间的闲谈,就会成为相当严重的有意的中伤,当然就会影响到朋友之间的感情。 节选自罗兰《宽以待人》

1. 下列哪一项不是“静坐常思已过”的好处?
A减少得罪人的机会。
B改正了自己的缺点。
C明白了自己的过失而得到一些警惕。
D反省别人对待我们有哪些疏忽或亏欠的地方。

2. “假如我们都知道别人在背后怎样讨论我们的话,恐怕连一个朋友也没有了。”这句话主要的用意是在提醒我们什么?

3. 本文认为,人们背后一时兴之所至,谈论他人的过失或缺点,是
A 不够朋友的表现 B 歪曲事实的表现
C 人之常情的表现 D 性格卑劣的表现

答案: 1 D 2背后的闲话不需认真计较 3 C

读书并不在多,最重要的是选得精,读得彻底。与其读十部无关轻重的书,不如以读十部书的时间和精力去读一部真正值得读的书;与其读十部书都只能泛览一遍,不如取一部书精读十遍。“好书不厌百回读,熟读深思子自知”这两句诗值得每个读书人悬为座右铭。读书原为自己受用,多读不能算荣誉,少读也不能算羞耻。少读如果彻底,必能养成深思熟虑的习惯,涵泳优游,以至于变化气质;多读而不求甚解,则如驰骋十里洋场,虽珍奇满目,徒惹心花意乱,空手而归。世间许多人读书只为装点门面。如暴发户炫耀家私,以多为贵。这在治学方面是自欺欺人,在做人方面是趣味低劣。 节选自朱光潜《谈读书》
注:十里洋场:比喻热闹繁华的地区。

1. 作者认为,真正的读书应该是
A 多读而不求甚解 B 熟读深思好的作品
C读书多是最高的荣誉 D 书读得少的人通常兴趣也比较低劣

2. “世间许多人读书只为装点门面”意思是
A 为了提高身份与地位而读书 B 为了养成深思熟虑的习惯
C 可以出口成章,充实内涵 D 想赚大钱住豪宅

3. 根据本文,哪一个不是读书的目的?
A 自己受益 B 变化气质
C 受人尊敬 D 养成深思熟虑的习惯

答案: 1 B 2 A 3 C

在海边捡起的这一枚贝壳的时候,里面曾经居住过的小小柔软的肉体早已死去,在阳光、砂粒和海浪的淘洗之下,贝壳中生命所留下来的痕迹已经完全消失了。但是,为了这样一个短暂和细小的生命,为了这样一个脆弱和卑微的生命,上苍给它制作出来的小居所却有许多精致、多仔细、多么地一丝不苟呢!
比起贝壳里的生命来,我在这世间能停留的时间和空间是不是更长和更多一点呢?是不是也应该用我的能力来把我所能做到的事情做得更精致、更仔细、更加地一丝不苟呢?
请让我也能留下一些令人珍惜、令人惊叹的东西来吧。
在千年以后,也许会有人对我留下的痕迹反复观看,反复把玩,并且会忍不住轻轻地叹息:“这是一颗怎样固执又怎样简单的心啊!” 节选自席慕蓉《贝壳》

1. 本文表现出作者什么样的生活态度?

2. 作者从一枚小贝壳中得到什么启示?
A 生于忧患,死于安乐。 C 万物静观皆自得,四时佳兴与人同。
B 君子疾没世而名不称焉。 D 人生得意须尽欢,莫使金樽空对月。

3. 作者所谓“我留下的痕迹”,应该是指
A 贝壳 B 砂粒 C 固执的心 D 文艺创作

答案: 1积极进取 2 B 3 D
老张(假定有这么一个人)驾驶汽车,送一个得了急病的邻居就医。路上车辆很多,秩序紊乱,而且每隔一百多公尺就有一个十字路口。老张心里急得要命,可是他不能闯红灯,不能按喇叭,不能超车抢道,他得耐着性子,在缓缓的车流中若无其事。
老张是办急事,而且是做好事,别人可能只不过是下班回家或出城兜风。尽管如此,他不能希望众车回避,绿灯常开,由他呼啸一声直驰而过。他得遵守交通规则,尊重一切别的车辆。否则,他的车子也许早已四轮朝天,不但病人延误了急救的机会,他自己也要头破血流了。
做事要耐烦,做好事尤其如此。做坏事的人自知理屈,能忍受一切盘根错节之处,做好事理直气壮,容易愤慨负气,以致人间好事多磨,而坏事常成。昔人说:世上多少好事,被坏人破坏了!也有多少好事,被好人办坏了!好人怎会办坏了好事呢?他心里当然是希望办好的,可是他缺少“成事”必须的韧性——他有的是“任性”,认为他是好人,不屑于“忍气吞声”,事成了是你们的好处,事败了我没有损失。好吧,那就让它失败,给你们一点教训!

节选自王鼎均《得礼让人》

1. 作者举老张的例子,告诉我们如果得礼不让人,可能会
A 马到成功 B功亏一篑
C 弄假成真 D 头破血流

2. “做坏事的人自知理屈,能忍受一切盘根错节之处”,文中“盘根错节”是比喻事情______。

3. 为什么“好人会办坏好事”?

答案: 1 B 2复杂难处理 3因为好人常任性,缺乏成事必须的韧性。

写作,其实和生活有很大的关系。梁实秋先生曾经提到作文的三个阶段。他说:
第一阶段在初提笔时,容易感觉文思苦涩难以为继,或搜寻枯肠,敷衍成篇,自己也觉得内容贫乏索然寡味。
第二阶段是提起笔来,有个我在,对于什么意见都有意见;而且触类旁通,或枝节横生;有时逸出题目而莫知所云;有时旁征博引而轻重倒置。
第三阶段是要懂得割爱。不成熟的思想,不稳妥的意见,不切题的材料,不扼要的描写,不恰当的词字,统统要大刀阔斧的加以削删。删除枝蔓之后,才能显著整洁而有精神,清除而有姿态,简单而有力量。
第一阶段和读书少,学识不足,以及充实了学问,甚至见闻,但仍缺乏思想的启发有关。第二阶段则是思想不够分明、冷静,也不能节制自己的天马行空。第三阶段是精简浓缩,句句切题,贵精不贵多,能够舍得。
如此看来,写作和生活实在很密切。多读书才能改变气质,增加心灵的视野,思想的深度。而培养个人的条理纪律,保持不随便任意评论的习惯;以及如同面对自己喜爱的文字,对自己喜爱的事物,如不切实际,就要割舍。写作,能够发表,甚至得到知音,也有实质的收获,那是最好不过的事。否则,以写作来训练自己对于生活的态度,增加自己内在的克制力,启发智性潜能,也都是极为有意义的人生练习。 节选自杨国明《人生练习——写作》
注:搜索枯肠:比喻竭力思索。
1. “容易感觉文思苦涩难以为继,或搜寻枯肠,敷衍成篇”的原因是什么?

2. “写作需割爱”,意思是文章
A 需触类旁通 B贵精不贵多
C 不需引用太多事例 D 不要随便任意评论

3. 作者认为写作和生活的关系
A 毫无关系 B 非常密切
C 写作对生活毫无实质助益 D 写作对生活是一种甜蜜的负担

4. 下列哪一句成语是对文章内容正面的夸奖?
A 索然寡味 B 不知所云
C旁征博引 D味同嚼蜡

答案: 1读书少,学识不足。 2 B 3 B 4 C

读寻人启事的时候,女孩正坐在长椅上,浓浓的树阴牢牢笼罩着椅子,这就像母爱,寒冷而郁闷,女孩无言。
用女孩的逻辑讲,母亲不疼她,母亲除了爱好挣钱之外,最大的偏爱就是苛求她。必须、不准、专制、独裁是女孩给母亲的定义,并作为对母亲的代称。
离开这个没有温暖的家,女孩蓄谋已久了。女孩在留下这样一张纸条后,终于把计划变成现实:“妈,我走了,按您的意思去把铁变成钢。别找我,我会活得很好。别忘了,我很漂亮。”
读这留言,女孩感到报复的快意。
令女孩满意的是,母亲第二天就调动了A市的新闻媒体,登了寻人启事,这要花很多钱的。能让母亲花不必要的钱,女孩心里高兴。
你永远找不到我。女孩甩头向火车站走去。在B市,女孩卖报、做工。只有在离家的时候才能品味出家的温暖。
半个月后,母亲把寻人启事散发到了B市,这次的寻人启事颇有一些检讨书的味道:女儿,回来吧,妈不再……不再……女孩开始惭愧。可不能就这么投降,女孩咬咬牙又去了C市。
每天晚上抱着寻人启事的报纸入眠,已经成了离家后女孩的一种习惯。在C市的两个月里,没有新的寻人启事,女孩感到失落和不安。
后来,女孩终于在《C市日报》上找到了一篇与自己有关的文字,但不是寻人启事,而是一则生日祝福:“女儿,生日快乐!”短短的几个字让女孩失眠了。
给母亲打电话,女孩第一次拨通了那个自己私下默念过百遍、千遍的号码。“此用户寻女未归,请留言。”挂上电话,女孩已泪流满面。
合同期总算结束了,女孩风尘仆仆赶回A市,她颤抖着按响了门铃,开门的却是个陌生人。原来,为了筹资找女儿,几天前,母亲将房子卖掉,去了南方。
第二天,报纸上多了一则启事:
寻母,速归。
金文吉《寻人启事》
1. 第三段“没有温暖的家”是什么意思?
2. 请根据文章内容对“没有温暖”作出具体说明。
3. 文章第四段说“读这留言,女孩感到报复的快意”,请写出这“留言”中所包含的“报复的快意”。
4. 把“母亲”的三次“寻人启事”看作一个变化过程,你从中读出了什么?女儿三次读“寻人启事”及给母亲打电话后的心态变化说明了什么?

答案:
1. 母亲只顾挣钱,忽略了对女儿的精神关爱。
2. 对女儿限制太多。
3. 女孩借母亲的话来讽刺母亲;没有你,我活的更好;我可能利用美貌作为资本来求得生存。
4. 母亲认识到了自己的不足,正在改变对女儿的态度。女儿一步一步理解了母亲,加深了对母亲的感情。

Differences of Ionic Compound and Covalent Compound

Covalent Compound – covalent bonding is strong bonding between the atoms in the molecule
Ionic Compound Differences Covalent Compound
Ions Particles Molecules
Lost or gained Electron Shared
Strong electrostatics forces (Ionic bond) between the oppositely-charged ions arranged in a 3-D giant crystal lattice Forces Strong (Covalent bond) between the atoms in the molecule. Weak forces of attraction between the molecules (van der Waals’ forces)
Solid State Gases or volatile liquids
High Melting point Low (Simple molecules)High (Giant molecules)
High Melting point Low (Simple molecules)High (Giant molecules)
Non-volatile Volatility Very volatile (Simple molecules)Non-volatile (Giant molecules)
Dissolve in water and polar solvents Solubility in water Do not dissolve in water
Do not dissolve in organic solvent Solubility in organic solvent Dissolve in organic solvent (ether, alcohol, benzene, tetrachloromethane and propanone)
Conduct electricity in liquid and aqueous solution (positive and negative ions can move freely). Cannot conduct electricity in solid state (fixed position and cannot move freely). Electricity conductor Cannot conduct electricity in any state (no free mobile ions)
Uses of covalent compounds as solvent
  • Ether – solvents in the extraction of chemicals from aqueous solution
  • Alcohol – solvents used to make ink and dye because these solvent are volatile
  • Turpentine – dissolved paint
  • CFC (chlorofluocarbons) – solvents to clean computer circuits board
  • Propanone – remove nail varnish

Tuesday, May 29, 2012

Predict the Products of Electrolysis of Aqueous Solutions

Predict the Products of Electrolysis of Aqueous Solutions
Main factor: Position of ions in the electrochemical series
  • Cation: The higher the position in the electrochemical series are very stable (remain as cation). Example: K+ and Na+ are never discharged in an aqueous solution in electrolysis.
  • Anions: The higher the position in the electrochemical series are very stable (remain as anion). Example: F - and SO42- are never discharged in an aqueous solution in electrolysis.
Second factor: Concentration of the electrolyte
Third factor: Types of electrode as anode
Electrolysis in Industries
A. Extraction of reactive metals
  • Reactive metals: Sodium, calcium, magnesium and aluminium extract from their compounds
  • Example: extraction of aluminium from aluminium oxide, Al2O3 (bauxite) by using cryolite, Na3AlF6 at 980˚C.
B. Purification of metals
  • Anode: impure metal
  • Cathode: pure metal
  • Electrolyte: solution containing the ions of the metal to be purified
  • Example: purification of impure copper metal.
C. Electroplating of metals
  • Electroplating is a process of coating the surface of metal objects with a thin and even layer of another metal.
  • Importance of electroplating is to prevent corrosion and improve the appearance.
  • Cathode: object to be electroplated
  • Anode: pure plating metal
  • Electrolyte: aqueous solution contains plating metal ions

Electrolysis of Molten Compounds

Electrolysis of Molten Compounds
  • Electrolysis (with battery / electricity current) is a process of decomposition / breaking down / separation of a compound (electrolyte) into its constituent elements when electric current passes through it.
Important definition
Anode Electrode connected to the positive terminal (+) of a battery
Cathode Electrode connected to the negative terminal (-) of a battery
Anion Negatively-charged ion. Example: Cl-, SO42- and O2-
Cation Positively-charged ion. Example: Na+, Zn2+ and Al3+
Classification of electrodes
Inert electrodes Electrodes that do not take part in chemical reactions during electrolysis Carbon or platinum
Active electrodes Electrodes that take part in chemical reactions during electrolysis Copper or zinc

Electrolysis of Aqueous Compounds (dissolved in water, H2O)
There are three important factors to determine the types of ions to be discharged at the electrodes.
  1. Positions of ions in the electrochemical series
  2. Concentration of ions in the solution
  3. Types of electrodes used
1. Positions of ions in the electrochemical series
The lower the position of the ion in the electrochemical series, the easier the ion is selectively discharged.
Electrochemical series:
Cation Anion
K+ F-
Na+ SO42-
Ca2+ NO3-
Mg2+ Cl-
Al3+ Br-
Zn2+ I-
Fe2+ OH-
Sn2+
Pb2+
H+
Cu2+
Hg+
Ag+
Au+

2. Effect of concentration of ions in the solution
The concentration of a particular type of ion is high = ion more likely to be discharged in electrolysis.

3. Types of electrodes used in the electrolysis
There are 2 important notes:
  • Inert electrodes: Carbon and platinum (Both of these electrodes do not react with the electrolytes or products of electrolysis)
  • Active electrodes: Silver, copper and nickel (Active anode ionises and concentration of cations in the electrolyte does not change)

Electrolyte

Voltaic Cell 
Electrolyte
  • Electrolytes are substances that can conduct electricity in molten or aqueous state and undergo chemical changes.
  • It can conduct electricity due to the presence of free moving ions.
Example for electrolytes (alkalis, acids, salt solution or molten salt):
  • molten lead(II) chloride
  • copper(II) sulphate solution
  • solution containing ions such as hydrochloride acid
Non-electrolyte
  • Non-electrolytes are molecules that cannot conduct electricity and will not undergo any chemical changes.
  • It cannot conduct electricity due to the absent of free moving ions.
Example of non-electrolytes (covalent substances):
  • molten acetone
  • molten naphthalene
  • glucose solution
Conductor
  • Conductors are substances that can conduct electricity in solid or molten state but do not undergo any chemical changes.
  • It can conduct electricity due to the flow of electrons.
Example of conductor:
  • iron
  • graphite
  • mercury
Ionic Compounds
Solid state Molten state or aqueous state (dissolved in water)
Do not conduct electricity Can conduct electricity
Ions are held in a lattice -
Ions do not move freely Ions are free to move
Covalent Compounds
Solid state Molten state or aqueous state (dissolved in water)
Do not conduct electricity Do not conduct electricity
Exist in molecules Exist in molecules
Molecules do not have free moving ions Exception: HCl and NH3 exist as free moving ions in water

Chemical Equation

Chemical Equation
1. Importance of chemical equation:
The types of reactants; the physical conditions; the quantity of reactants and products and stated in moles.
nA + nB –> pC + pD
2. Reactants are written in the left side of the reaction and products are written in the right side of the reaction.

3. Information obtainable from chemical equations.
  • i) mass of reactants
  • ii) volume of reacting gas
  • iii) mass of products formed
  • iv) volume of gas produced

  • Example:
    2 cm3 of lead (II) nitrate solution is added to excess of potassium iodide solution.
    How many molecules of potassium nitrate will be formed?
    [Relative atomic mass: N, 14; O, 16; K, 39; I, 127; Pb, 207; Avogadro's constant: 6.02 x 1023 mol-1]
Step 1: Write a complete chemical equation.
  • Pb(NO3)2(aq) + 2KI(aq) –> PbI2(s) + 2KNO3(aq)
  • From the equation, 1 mole of Pb(NO3)2 reacts with 2 moles of KI formed 1 mole PbI2 of and 2 moles of KNO3.
Step 2: Convert to moles.
  • No. of moles of Pb(NO3)2
    = Mass of Pb(NO3)2 / Relative molecular mass
    = 2 / [207 + 2(14 + 3 x 16)]
    = 6.04 x 10-3 mol
Step 3: Ratio of moles.
  • Number of moles of KNO3/ Number of moles of Pb(NO3)2
    = 2/1
  • Number of moles of KNO3
    = (2 x 6.04 x 10-3) / 1
    = 12.08 x 10-3 mol
Step 4: Convert to the number of molecules of potassium nitrate.
  • Number of molecules of KNO3
    = 12.08 x 10-3 x 6.02 x 1023
    = 7.27 x 1021
 

Empirical and Molecular Formulae

Empirical and Molecular Formulae
1. Empirical (simplest ratio of atoms of each element that present in the compound) and molecular formulae (actual number of atoms of each element that are present in one molecule of the compound) indicate:
  • the types of the elements
  • the symbols of the elements and the ratio of atoms or
  • moles of atoms of each element in a compound.
2. Molecular formula = (empirical formula)n
n is a positive number
Compound Molecular formula n Empirical formula
Carbon dioxide CO2 1 (CO2) = CO2
Ethane CH3 2 (CH3)2 = C2H6
Propene CH2 3 (CH2)3 = C3H6
Glucose CH2O 6 (CH2O)6 = C6H12O6
Quinine C10H12NO 2 C20H24N2O2
3. Chemical formulae for covalent compounds.
Name Chemical formula Number of each element
Nitrogen gas N2 2 nitrogen atoms
Oxygen gas O2 2 oxygen atoms
Ammonia NH3 1 nitrogen atom and 3 hydrogen atoms
Water H2O 2 hydrogen atoms and 1 oxygen atom
4. Cations are positively-charged ions.
Charge Cations Formula
+1 Ammonium ion NH4+
+1 * Copper(I) ion Cu+
+1 Hydrogen ion H+
+1 Lithium ion Li+
+1 * Nickel(I) ion Ni+
+1 Potassium ion K+
+1 Silver ion Ag+
+1 Sodium ion Na+
+2 Barium ion Ba2+
+2 Calcium ion Ca2+
+2 * Copper(II) ion Cu2+
+2 * Iron(II) ion Fe2+
+2 * Lead(II) ion Pb2+
+2 Magnesium ion Mg2+
+2 * Manganese(II) ion Mn2+
+2 Nickel(II) ion Ni2+
+2 * Tin(II) ion Sn2+
+2 Zinc ion Zn2+
+3 Aluminium ion Al3+
+3 * Chromium(III) ion Cr3+
+3 * Iron(III) ion Fe3+
+4 * Lead(IV) ion Pb4+
+4 * Tin(IV) ion Sn4+
* refer to the Roman numerals
5. Anions are negatively-charged ions.
Charge Anions Formula
-1 Bromide ion Br-
-1 Chloride ion Cl-
-1 Chlorate(V) ion ClO3-
-1 Ethanoate ion CH3COO-
-1 Fluoride ion F-
-1 Hydride ion H-
-1 Hydroxide ion OH-
-1 Iodide ion I-
-1 Manganate(VII) ion MnO4-
-1 Nitrate ion NO3-
-1 Nitrite ion NO2-
-2 Oxide ion O2-
-2 Carbonate ion CO32-
-2 Chromate(VI) ion CrO42-
-2 Dichromate(VI) ion Cr2O72-
-2 Sulphide ion S2-
-2 Sulphate ion SO42-
-2 Sulphite ion SO32-
-2 Thiosulphate ion S2O32-
-3 Nitride ion N3-
-3 Phosphate ion PO43-
-3 Phosphite ion PO33-
6. Chemical formulae for ionic compounds
Name Chemical formula Number of cation Number of anion
Zinc chloride ZnCl2 1 Zn2+ 2 Cl-
Copper(II) sulphate CuSO4 2 Cu2+ 2 SO42-
Aluminium sulphate Al2(SO4)3 2 Al3+ 3 SO42-
7. Meaning of prefixes
Prefix Meaning
Mono- 1
Di- 2
Tri- 3
Tetra- 4
Penta- 5
Hexa- 6
Hepta- 7
Octa- 8
Nona- 9
Deca- 10
8. Naming of chemical (non-metal) compounds with Greek numerical prefixes.
Non-metal compound Chemical formula
Carbon monoxide CO
Carbon dioxide CO2
Sulphur dioxide SO2
Sulphur trioxide SO3
Carbon tetrachloride (tetrachloromethane) CCl4

Chemical Formulae

1. Relative atomic mass, Ar is the atomic mass of an atom when compared to a standard atom
2. Standard atom:

Carbon scale: standard atom of comparison internationally.
  • a carbon-12 atom is 12 times heavier than an atom of hydrogen,
  • used as the reference standard in mass spectrometers,
  • exists as a solid at room temperature,
  • most abundant carbon isotope, happening about 98.89% and
  • carbon-12 is close to the agreement based on oxygen.
3. Relative molecular mass, Mr of a substances is the average mass of a molecule (two or more atoms) of the substances when compared 1/12 with of the mass of a carbon-12 atom.
4. Relative formula mass, Fr is for ionic compound which is calculated by adding up the relative atomic masses of all the atoms.

5. Avogadro constant / Avogadro’s number is 6.02 x 1023
6. Atomic substances
  • Elements – all the particles are atoms.
  • Example: zinc (Zn), sodium (Na), aluminium (Al) and all noble gases, argon (Ar), helium (He) and neon (Ne).
  • RAM (Relative Atomic Mass) of  Na = 23
7. Molecular substances
  • Covalent compounds – the particles are molecules.
  • Example: carbon dioxide (CO2), water (H2O) and non-metal elements, iodine (I2), nitrogen (N2) and oxygen (O2).
  • RMM (Relative Molecular Mass) of I2 = 127 + 127 = 254
8. Ionic substances
  • Ionic compounds – the particles are ions.
  • Example: sodium chloride (NaCl), hydrochloric acid (HCl) and potassium iodide (KI).
  • RFM (Relative Formula Mass) of HCl = 1 + 35.5 = 36.5
9. Avogadro’s Law / Gas Law states that equal volumes of all gases contain the same number of molecules under the same temperature and pressure.
  • Example: equal volumes of molecular hydrogen and nitrogen would contain the same number of molecules under the same temperature and pressure.
10. Volume of gas (dm3) = Number of moles of gas x Molar volume
11. Room temperature and pressure (r.t.p.) = 24 dm3 mol-1 (25°C and 1 atm)

Ionic Bonds

Ionic Bonds
  • It is a chemical bond formed from the transfer of electrons from metal atoms to non-metal atoms
  • Metal atoms donate valence electrons to form positive ions (cations, Mb+) and achieve the stable duplet or octet electron arrangement of the noble gases
  • Non-metal atoms receive electrons to form negative ions (anions, Xa-) and achieve the stable duplet or octet electron arrangement of the noble gases
  • Cations and anions are attracted to each other by strong electrostatic force of attraction
Example:
Metal + Non-metal –> Ionic compound
Sodium + bromine –> Sodium bromide
Calcium + chlorine –> Calcium chloride
Lithium + oxygen –> Lithium oxide
Aluminium + nitrogen –> Aluminium nitride
Metals
Group 1
  • A lithium atom with an electron arrangement of 2.1 achieves stability after it donates one valence electron to form a lithium ion, Li+. The electron arrangement of the lithium ion, Li+, is 2 with stable duplet electron arrangement.
  • A sodium atom with an electron arrangement of 2.8.1 achieves stability after it donates one valence electron to form a sodium ion, Na+. The electron arrangement of the sodium ion, Na+, is 2.8 with stable octet electron arrangement.
  • A potassium atom with an electron arrangement of 2.8.8.1 achieves stability after it donates one valence electron to form a potassium ion, K+. The electron arrangement of the potassium ion, K+, is 2.8.8 with stable octet electron arrangement.
Group 2
  • A magnesium atom with an electron arrangement of 2.8.2 achieves stability after it donates two valence electrons to form a magnesium ion, Mg2+. The electron arrangement of the magnesium ion, Mg2+, is 2.8 with stable octet electron arrangement.
  • A calcium atom with an electron arrangement of 2.8.8.2 achieves stability after it donates two valence electrons to form a calcium ion, Ca2+. The electron arrangement of the calcium ion, Ca2+, is 2.8.8 with stable octet electron arrangement.
Group 13
  • An aluminium atom with an electron arrangement of 2.8.8.3 achieves stability after it donates three valence electrons to form an alumium ion, Al3+. The electron arrangement of the aluminium ion, Al3+, is 2.8.8 with stable octet electron arrangement.
Non-metal
Group 15
  • A nitrogen atom with an electron arrangement of 2.5 achieves stability after it accepts three valence electrons to form a nitride ion, N3-. The electron arrangement of the nitride ion, N3-, is 2.8 with stable octet electron arrangement.
  • A phosphorus atom with an electron arrangement of 2.8.5 achieves stability after it accepts three valence electrons to form a phosphoride ion, P3-. The electron arrangement of the phosphoride ion, P3-, is 2.8.8 with stable octet electron arrangement.
Group 16
  • An oxygen atom with an electron arrangement of 2.6 achieves stability after it accepts two valence electrons to form a oxide ion, O2-. The electron arrangement of the oxide ion, O2-, is 2.8 with stable octet electron arrangement.
  • A sulphur atom with an electron arrangement of 2.8.6 achieves stability after it accepts two valence electrons to form a sulphide ion, S2-. The electron arrangement of the sulphide ion, S2-, is 2.8.8 with stable octet electron arrangement.
Group 17
  • A fluorine atom with an electron arrangement of 2.7 achieves stability after it accepts one valence electron to form a fluoride ion, F -. The electron arrangement of the fluoride ion, F -, is 2.8 with stable octet electron arrangement.
  • A chlorine atom with an electron arrangement of 2.8.7 achieves stability after it accepts one valence electron to form a chloride ion, Cl -. The electron arrangement of the chloride ion, Cl -, is 2.8.8 with stable octet electron arrangement.
Predict the Formula of an Ionic Compound
  • Cation Mb+
  • Anion Xa-
  • Formula of an ionic compound formed, MaXb
Formulae for ionic compound
Metal atom, M Non-metal atom, X Ionic Compound
Group 1 Group 15 M3X
Group 1 Group 16 M2X
Group 1 Group 17 MX
Group 2 Group 15 M3X2
Group 2 Group 16 MX
Group 2 Group 17 MX2
Group 13 Group 15 MX
Group 13 Group 16 M2X3
Group 13 Group 17 MX3
Some common ionic compound
  • Sodium chloride (NaCl)
  • Magnesium oxide (MgO)
  • Calcium sulphide (CaS)
  • Potassium oxide (K2O)
  • Magnesium fluoride (MgF2)

Structure of ionic compounds
  • The oppositely-charged ions, Mb+ and Xa- are attracted to each other by a strong electrostatic force.
  • It form a rigid 3-dimensional lattice structure
  • Formed crystal.
  • Giant ionic lattice.

Covalent Bonds

Covalent Bonds
  • It is a chemical bond formed from the sharing of valence electrons between non-metal atoms to achieve the stable duplet of octet electron arrangement.
  • Each shared pair of electrons is as one covalent bond.
  • It produces molecules.
  • Usually the covalent bonds form between non-metal atoms from Group 15, 16 and 17 and sometimes can be formed from Group 14 (carbon and silicon) and hydrogen.
  • Covalent bond can be formed from atoms of the same element and atoms of different elements.
Example:
Non-metal + Non-metal –> Covalent compound
Bromine + bromine –> Bromine (Br2)
Nitrogen + nitrogen –> Nitrogen (N2)
Carbon + chlorine –> Tetrachloromethane (CCl4)
Hydrogen + oxygen –> Water (H2O)
Hydrogen + nitrogen –> Ammonia (NH3)
Types of covalent bond formed:
  • Single bond = one pair of electrons shared between two atoms.
  • Double bond = two pair of electrons shared between two atoms.
  • Triple bond = three pair of electrons shared between two atoms.
Non-metal
Group 15
  • A nitrogen atom with an electron arrangement of 2.5 needs three more electrons to achieve stable octet electron arrangement after it contribute (through sharing) three valence electrons to another atom (can be from Group 14, 15, 16, 17).
  • A phosphorus atom with an electron arrangement of 2.8.5 need three more electrons to achieve stable octet electron arrangement after it contribute (through sharing) three valence electrons to another atom (can be from Group 14, 15, 16, 17).
Group 16
  • An oxygen atom with an electron arrangement of 2.6 needs two more electrons to achieve stable octet electron arrangement after it contribute (through sharing) two valence electrons to another atom (can be from Group 14, 15, 16, 17).
  • A sulphur atom with an electron arrangement of 2.8.6 need two more electrons to achieve stable octet electron arrangement after it contribute (through sharing) two valence electrons to another atom (can be from Group 14, 15, 16, 17).
Group 17
  • A fluorine atom with an electron arrangement of 2.7 needs one more electron to achieve stable octet electron arrangement after it contribute (through sharing) one valence electron to another atom (can be from Group 14, 15, 16, 17).
  • A chlorine atom with an electron arrangement of 2.8.7 need one more electron to achieve stable octet electron arrangement after it contribute (through sharing) one valence electron to another atom (can be from Group 14, 15, 16, 17).
Predict the Formula of a Covalent Compound
  • Non-metal X atom (valence electron is a)
  • Combine with another non-metal Y atom (valence electron is b)
  • b = simplest ratio (n) and a = simplest ratio (m)
  • Formula of a covalent compound formed, XnYm
 Some common covalent compound
  • Hydrogen molecule, H2 (single bond)
  • Chlorine molecule, Cl2 (single bond)
  • Bromine molecule, Br2 (single bond)
  • Fluorine molecule, F2 (single bond)
  • Water molecule, H2O (single bond)
  • Nitrogen trifluoride molecule, NF3 (single bond)
  • Tetrachoromethane / carbon tetrachloride, CCl4 (single bond)
  • Ammonia molecule, NH3 (single bond)
  • Oxygen molecule, O2 (double bond)
  • Carbon dioxide molecule, CO2 (double bond)
  • Nitrogen molecule, N2 (triple bond)
  • Ethyne molecule, C2H2 (triple bond)
Structure of covalent compounds
  • Can be simple molecular structure or giant molecular structure.
  • The atoms in the molecule are joined together by strong covalent bond but intermolecular forces are weak by weak van der Waals’ forces.

Chemical Bonds

Formation of Compounds
  • Compounds – different elements that chemically bonded together
  • Octet electron arrangement – electron arrangement of an atom where the outermost occupied shell is filled with eight valence electrons
  • Duplet electron arrangement – electron arrangement of an atom where a single shell filled with two valence electrons
Example:
Compound water is hydrogen and oxygen atoms are chemically bonded together.
Stability of Noble Gases
  • Atom of noble gas does not gain, lose nor share electrons with other atoms.
  • Noble gas atoms do not combine with atoms of other elements to form compounds or with each other to form molecules.
  • Noble gases are chemically unreactive.
  • Noble gases exist as monoatomic.
Chemical Bonds
Chemical Bond
Chemical Bond
Types of chemical bonds:
  • ionic bonds (metal + non-metal)
  • covalent bonds (non-metal + non-metal)
Atoms of other elements can achieve the stable octet electron arrangement by
  • transfer of electrons
  • sharing of electrons

Cell Organisation

Cell Organisation
Unicellular – A single cell performs all the basic life process. Example: Amoeba sp., Paramecium sp., Chlamydomonas, Bacteria and Euglena.
Multicellular – An organism consists of more than one cell. Each group of cell specialized to carry our life processes. Example: Homo sapien (human), animals and plants. It has five levels of organisation
  1. Cells: basic units of structure and function.
    Example: Red blood cells and xylem vessel cells.
  2. Tissues: made up of cells with similar in structure and function.
    Example: Epithelial tissues and vascular tissues.
  3. Organs: made up of tissues that perform a specific function.
    Example: Heart and flower.
  4. System: two of more organs that perform a specific function.
    Example: Digestive system and root system.
  5. Organisms: whole living thing that carry out all the basic life processes.
    Example: Human and durian tree.
Cell Organisation (Unicellular) in Amoeba sp. (lives in freshwater ponds) and Paramecium sp. (lives in soil and moist area)


1. Cell structure
  • Amoeba sp.: plasma membrane, food vacuole, contractile vacuole, pseudopodium, nucleus, ectoplasma, endoplasm.
  • Paramecium sp.: food vacuole, posterior contractile vacuole, cytostome, gullet, oral groove, cilia, macronucleus, micronucleus, anterior contractile vacuole.
2. Locomotion
  • Amoeba sp.: Pseudopodium (false foot) helps it to move forward slowly and it is known as amoeboid movement.
  • Paramecium sp.: Hair-like cilia to beat against water. It beats its cilia backwards diagonally (swim forward) and it rotates on its axis. It beats its cilia forward (swim backwards).
3. Feeding
  • Amoeba sp.: Omnivore. Eat bacteria, plant cells, algae and other microscopic organisms.
  1. Entrapment – extend pseudopodium.
  2. Engulfment – engulf tiny food (phagocytosis) with its pseudopodia.
  3. Digestion – food enclosed in food vacuole
  4. Absorption – enzyme digests the bacteria
  5. Egesting – expel indigestible material.
  • Paramecium sp.: Eat bacteria, organic material and other microscopic organisms.
  1. Sweeping – movement of cilia. Food moves along the oral groove into the gullet and cytostome.
  2. Digestion – food vacuole circulates round the cell.
  3. Elimination – undigested food is eliminated at the anal pore.

4. Reproduction
  • Amoeba sp.: two types of reproduction.
  1. Binary Fission – nucleus divides (favourable condition) and then follows by division of cytoplasm. Two daughter cells are formed (mitotic division).
  2. Spore Formation – spores form (bad condition) and germinate into new amoeba under favourable condition.

  • Paramecium sp.: two types of reproduction.
  1. Binary Fission – micronucleus undergoes mitosis (favourable condition). Macronucleus begins to elongation and form two. Cell content divide and two daughter cells are formed.
  2. Conjugation (Sexual reproduction) – two same species parent paramecia exchange genetic material of their micronuclei. Each parent divides and forms four daughter cells.
5. Osmoregulation
  • Amoeba sp.: water moves into the cell by osmosis and prevention of bursting, it has a contractile vacuole.
  • Paramecium sp.: water moves into the cell by osmosis and prevention of bursting, it has two contractile vacuoles.


6. Respiration
  • Amoeba sp. and Paramecium sp. (both): exchange gases throughout the whole cell membrane
7. Excretion
  • Amoeba sp. and Paramecium sp. (both): waste products are ammonia and carbon dioxide by diffusion. Solid waste in paramecium is expelled through its anal pore.





Cell Organisation (Multicellular) in Human
  1. Cells: Epithelial cells, muscle cells, white blood cells, red blood cells, sperm, nerve cells.
  2. Tissues: Epithelial tissue, smooth muscle tissue, connective tissue, skeletal tissue, nerve tissue.
  3. Organs: Stomach, heart, kidney, lung, liver.
  4. Systems: Circulatory system, respiratory system, digestive system, excretory system, muscular system, lymphatic system, integumentary system, skeletal system, nervous system, endocrine system, reproductive system.
  5. Organisms: Human.
Cell Organisation in Plant
  1. Cells: Parenchyma cells, collenchyma cells, sclerenchyma cells, epidermal cells.
  2. Tissues: Epidermal tissue, meristem tissue, vascular tissue.
  3. Organs: Leaf organ, flower organ, stem organ, root organ.
  4. Systems: Shoot system, root system.
  5. Organisms: Plant.

Cell Structure and Function

Cell Structure and Function
Comparison between Animal Cell (AC) and Plant Cell (PC)
1. Mitochondrion (pl: Mitochondria): AC and PC
  • spherical / rod-shaped organelles
  • two membranes: Inner membrane – form cristae & Outer membrane – regular and smooth
  • an energy source
  • site of cellular aerobic respiration
  • produces ATP (adenosine triphosphate)
2. Nucleus (pl: Nuclei): AC and PC
  • contains the genetic material
  • regulates and controls the activities of the cell
  • an organelle bounded by double (2) layers of nuclear membrane with pores and selectively permeable
  • responsible for all cellular structure, chemical functions, growth and reproduction
  • separates the genetic materials (chromatin) from cytoplasm
3. Nucleolus: AC and PC
  • spherical structure within the nucleus
  • consists of DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) and proteins
  • visible when the cell is not dividing
  • synthesis RNA which is needed to make ribosomes
4. Nucleoplasm: AC and PC
  • fluid contained within the nucleus
  • highly viscous solid
  • made up of the chromatin and the nucleolus
5. Chromosomes
  • thread-like structures (consists of genetic material)
  • appears as chromatin spread throughout the nucleus in the form of tiny granules
  • chromatin condenses into chromosomes (during cell division)
  • carry genetic information in its DNA
6. Ribosomes: Ac and PC

  • small dot-like organelles
  • protein synthesis
  • consist of RNA (ribonucleic acids)
  • smallest cellular organelles
  • attached on the surface of ER and occur freely in cytoplasm
7. Endoplasmic reticulum (ER): AC and PC
  • connected to the nuclear membrane
  • synthesises proteins, steroids and lipids
  • collects, stores and distributes protein, steroids and lipids
  • exists as rough ER and smooth ER
  • Rough ER: covered with ribosomes, flat sealed sac which continued from the nuclear membrane, transports protein, and have a large surface area for chemical reactions.
  • Smooth ER: does not have ribosomes, transports lipids and presents in large amounts of cells.
8. Plasma membrane: AC and PC
  • cell membrane
  • thin membrane surround the cytoplasm of a cell
  • selectively permeable / semi permeable
  • a protective and selective outer barrier
  • consists of phospholipids and protein molecules
 9. Golgi apparatus / Golgi body: AC and PC
  • bound sacs
  • processes, packages and transport molecules synthesised in the cell
  • forms lysosomes
  • transports and stores lipids
  • synthesis of carbohydrate from hormone
  • changes protein into glycoprotein
  • excretes waste products out of the cell
10. Cytoplasm: AC and PC
  • aqueous solution (except nucleus)
  • stores water, enzymes, nutrient, salts and dissolved gases
  • provided support, shape and protects the cell organelles
  • medium for metabolic reactions
  • provides substances
11. Lysosome: AC
  • sac-like organelle with one membrane
  • digest proteins, lipids and carbohydrates
  • removes undigested materials
  • releases enzymes to digest external materials
12Centriole: AC
  • are paired cylindrical organelles
  • nine tubes with three tubules each
  • produces spindle during cell division (mitosis and meiosis)
  • migrate to the opposite poles of the cell (during cell division – will be discussed in Chapter 5 Cell Division)
13. Vacuole: AC (temporary / lower class species) and PC
  • small cavity in the cytoplasm
  • bound by a single membrane
  • filled with cell sap
  • storage of food (protein, oil and water)
  • some vacuoles remove metabolic waste
  • functions as cell expansion
  • Amoeba: food vacuoles (phagocytosis)
  • Paramecium: contractile vacuoles (expel water)
14. Cell Wall: PC
  • rigid and tough cellulose layer surrounding the plasma membrane (cell membrane)
  • protects and supports the cell
  • maintains the shape
  • prevents the cell from busting (excessive intake of water)
  • allows substances to move freely through the cell wall
15. Chloroplast: PC
  • disc / lens-shaped organelle
  • have two membranes: inner and outer membrane
  • contains chlorophyll in the grana to trap sunlight energy
  • carry out photosynthesis in the chlorophyll
  • storage of food and pigments

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