[DSE化學2019]同學準備好DSE CHEM未? (2)

基本要記methyl orange同phenolphthalein幾時用

dipole moment out 左 c, 如果係asymmetrical molecule 例如 NH3 解釋佢係polar, 之前會話N is more electronegative than H, N-H bond is polar, the molecule is asymmetrical and the dipole moments cannot cancel out each other, therefore the molecule is polar咁啦，如果我寫dipole moment 係咪唔比分，如果唔比，要改咩呀，我見有d書就咁改dipole moment 做polarity 係咪咁
同理 cis-ch2cl2 個boiling point 大過trans點解釋，dipole moment out 左c

搞錯左d野c2h2cl2至啱

唔會唔比分 事實係咁
其實我都建議寫返dipole moment 無謂夾硬搵第二個字取代佢

cis trans咪一樣用返asymmetrical > net dipole 去解

原來之前睇d片都係巴打拍，唔該曬巴打

咁樣應該計一個amide group定兩個amide group？

多謝你支持就真

urea係另一個series黎 dse無正式學的

2018 Paper2 infra-red spectrum C=C個absorption peak點睇到出黎？
同埋distinguish K2SO3 and K2SO4 用acidified KMnO4可唔可以？

C=C係好難睇 通常係估structure果時發現少左兩個H去推斷返

KMnO4 ok

different substance有different solubility in stationary phase and mobile phase

ok 唔該曬～

當然
隨你放咩solvent落去
用唔同solvent, 最後就會有不同既Rf value

giant molecular淨係識c=c整出黎既polymer就得
定係要識埋general properties

HPLC洗唔洗考？同埋mohr method 洗唔洗要自己知曬成個流程然後直接問你

另外想問點解co2+ [Al(OH)4]-會出Al(OH)3?

sulphurous acid 係 weak 定strong acid?
我睇acidic/alkaline hydrolysis of amide/ester 係organic chem 都要heat
但rate reaction 個課ester+naoh 唔使heat 都行到alkaline hydrolysis 既product 係咪其實acidic/alkaline hydrolysis of amide/ester 唔使heat 都行到，heat 個功能只係for faster the reaction?

唔考
佢會比資料你

CO2弱酸性
會慢慢拉低pH咁咪shift eqm LHS

weak架

yes唔heat會好慢

synthesis要寫明heat

重有electrolysis 如果cu 係anode, electrolyte 係cuso4(aq), Cu->Cu2+ +2e- , 但同時 Cu2+ +2e- ->Cu, 個effect cancel out左, Cu metal 個mass remains unchanged
有年past paper chemical cell 係mg in mgso4 solution 做 reducing agent, 因為mg 係strong reducing agent, 佢loses electrons, 之後出mg2+但mg2+ hardly reduced 所以唔會變返mg, mg dissolves.
我想問如果zn anode in znso4(aq), al anode in al2(so4)3係咪同mg 一樣都行唔到
zn2+ +2e- -> zn
al3+ +2e- -> al
zn 同al 都會dissolves and decrease in mass