[DSE化學2018]同學準備好DSE CHEM未?

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魏娘 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

化學艾維斯 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

化學艾維斯 2017-12-30 02:53:38

睇electrolyte用acid定alkali
H2 fuel cell alkaline cell黎

化學艾維斯 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

化學艾維斯 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

化學艾維斯 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

化學艾維斯 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

魏娘 2017-12-30 18:52:41