[DSE化學2018]同學準備好DSE CHEM未?

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89 Like 24 Dislike
2017-12-29 23:10:26
你講chemical cell果個?定cracking
Cracking果個原因真係查唔到
但chemical cell果隻又係咩？
cracking果個係catalyst 主要成分有Al2O3
mechanism上令carbon chain上既H抽走左 形成cation 進而令條chain rearrange而斷開

chemical cell果個純粹係有small hole容許ion有限度地通過 maintain the overall charge balance between two half cells (prevent internal resistance build up)
chemical cell 係咪得industrial chem嘅diaphragm cell 先係

Hydrogen-oxygen fuel cell 個nickel electrode 都係porous
仲有一個唔洗點識嘅daniell cell 都係
2017-12-30 02:51:54
cell個porous pot係allow ion pass through
作為salt bridge咁用

fuel cell既electrode整成porous係為左increase surface area so that increase the catalytic efficiency
2017-12-30 02:53:38
睇electrolyte用acid定alkali
H2 fuel cell alkaline cell黎
2017-12-30 13:48:30
technically speaking cracking to form hydrogen and carbon (especially under high temperature condition)
usually they are considered as side products (carbon will be burnt off) and we do not intend to obtain them from cracking process
http://www.essentialchemicalindustry.org/processes/cracking-isomerisation-and-reforming.html
2017-12-30 13:49:18
technically speaking cracking do form hydrogen and carbon (especially under high temperature condition)
usually they are considered as side products (carbon will be burnt off) and we do not intend to obtain them from cracking process
http://www.essentialchemicalindustry.org/processes/cracking-isomerisation-and-reforming.html
2017-12-30 15:39:29
public exam考cracking基本會focus on hydrocarbon products only
出版社exercise我建議做下清下concept無問題
但唔洗強求個分數 因為無乜邊間出既mock真係好貼近實際考試 一係就太離地 中學根本唔會識

我建議係得返3個月 儘量做多d pastpaper (Ce/AL/DSE)去摸熟個問法同答法
2017-12-30 15:45:17
唔太關事 有d mock根本個出法同難度都唔似公開試
另外呢 其實chem唔應該用mc做指標
因為mc同lq係同一份卷 mc佔36分 lq 84分
答啱多題lq已經等於兩三題mc

之前我有學生試過mc 36題全中 但出黎得lv 5
2017-12-30 18:07:26
想問一下 2013part 2 14題
點解將F加H2(pt)就變左飽和脂肪
同埋咩叫飽和脂肪
2017-12-30 18:52:41
想問一下 2013part 2 14題
點解將F加H2(pt)就變左飽和脂肪
同埋咩叫飽和脂肪

利申無題目係有

不飽和脂肪係有c=c

飽和脂肪係無c=c

不飽和+H2 -> 飽和
2017-12-30 18:58:42
想問一下 2013part 2 14題
點解將F加H2(pt)就變左飽和脂肪
同埋咩叫飽和脂肪

利申無題目係手

不飽和脂肪係有c=c

飽和脂肪係無c=c

不飽和+H2 -> 飽和
2017-12-30 19:09:37
明白
想問多一條係話個肥皂可以同CH3OH反應
問出咩
肥皂可以同醇反應架咩
2017-12-30 19:21:36
我溫書見到書有寫
Under some conditions, C and H2 will be formed
2017-12-30 19:34:11
碳化合物黎講 飽和即係無c=c或三鍵
c=c + H2 -> CH-CH
無左雙鍵叫飽和
2017-12-30 19:36:06
果個反應本身out syl的
酯同另一個醇反應 出另一個酯
叫tranesterification(酯交換作用)
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