2007年4月27日 星期五

會考化學(8)

同學仔唔好意思,因最近好忙,所以化學友post d 考試攻略同埋回覆問題比較慢,化學友e兩日如果有時間會寫多d o野o架喇。大家一齊add oil啦!!

今次化學友想同同學仔講吓paragraph length(段落式) question(一般人叫e d題目做essay),大家一定要對佢嘅出法要有d認識。同學仔做過05同埋06pastpaper都知道卷一有兩條呢d題目,一條出自核心部份而另一條出自延展部份。一般o黎講每條佔9分,6分係內容分而3分係傳意技能(communication)。

通常6分內容分即係要答6個points,記住at least要寫到6個points先好停手。仲有訝chem essay唔使要求你寫引子同埋結尾o架,所以唔好waste time去寫呀‧

至於傳意技能嘅3分係依據以下條件俾分:

1分係俾以paragraph length寫出(即使唔係用point form或者table,而係一段一段咁寫出o黎)

另1分係俾文章嘅前文後理通唔通順(如果用english寫essay,accuracy of using english都計埋o架)

最後1分係俾無化學知識上嘅失誤(例如你寫combustion of fuel in factories會產生CO2, SO2,而CO2 同埋SO2會引至global warming就會冇左e一分,因為SO2係唔會引至global warming)

至於今年化學友嘅熱門心水題包括

核心部份:
(i) Metal extraction (金屬提取);
(ii) Neutralization (中和作用);
(iii) Preparation of chlorine bleach and its reactions (氯漂白水製備及反應);
(iv) Preparation of sulphuric acid and its reactions (硫酸製備及反應);
(v) Distinguish different types of organic compounds (辨別不同類型有機化合物)
延展部份:
(i) Aluminium corrosion and anodization (鋁的腐蝕及陽極氧化);
(ii) Design experiment related to titration (設計與滴定法有關實驗);

(iii) Design experiment on rate of reaction (設計反應速率實驗)
(iv) Compare and contrast of soapy and soapless detergent (比較皂性與非皂性清潔 劑)


最後要remind同學仔:

1. 寫essay要用complete sentence。

2. 盡量唔好寫symbol或者formula,要寫全名,例如唔好寫C同埋NO要寫carbon同埋nitrogen oxide。

3. 一般唔好用多過十分鐘寫一條essay,你會冇時間做其他題目o架。

3 則留言:

pele159 提到...

請問寫essay 洗唔洗寫 equation ??


Preparation of sulphuric acid

係咪 Contact process ??

如果想整 Conc. Nitric acid 可以點整呀 ?

maryuen 提到...

化學友
我想知道怎麼看CH3CO2H->CH3CH2OH的oxidation no.?? oxidation no.是什麼??

1998 5
how to use the test tube given?
wt is the answer in the marking scheme?

7aiii3
why ethanol can dissolve unpolymerized monomer?(joint us answer)

7bii3
PVC is not suitable for making electric socket since the current pass through it will produce heat and melt it??

9aiii
how to write this equation with [O]?

9avi1
can i write a thin colourless layer form on top of the sodium carbonate solution??

pele159 提到...

1. 請問係咪有個新方法整 soap ( acid hydrolysis of fat or oil ) ?

Fat/oil + water ↔ fatty acids + glycerol

2. 整soapless detergent 係咪要 conc.H2SO4 & NaOH 呀 ??

3. 你上次答NaOH同hydrolysis裡面形成嘅carboxylic acid neutralize生成salt of carboxylic acid(即係soap)

咁我英文可以點答呀 ??

4. 請問點解 soap 係 alkaline ( 佢又冇OH-ion ) ?