[DSE化學2018]同學準備好DSE CHEM未?

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btw 依家拍緊elective題解
https://www.youtube.com/channel/UCPE9pbWdjviOfSWRn9V2kRQ
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跟住再拍埋core(差2012-2014)

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推！
同埋想問啲metal ore使唔使記曬

唔洗
只需就唔同metal既extraction method

Paper II 問how to test presence of Br-
點解唔可以add Cl2

利申：pish

Paper II 問how to test presence of Br-
點解唔可以add Cl2

利申：pish

oxidizing power: F2>Cl2>Br2>I2
so Cl2 + 2Br- -> Br2 + 2Cl-
the mixture turns reddish brown

用其他common OA都得
雖然唔係specific test for Br- 但考試都接受

Paper II 問how to test presence of Br-
點解唔可以add Cl2

利申：pish

要chlorine 可以displace 到br- chlorine 濃度較高 溶係水yellowish green 溝埋br2 orange color 根本好難睇到 加上br2 cl2其實都唔係好soluble 個reaction 會比較慢

可能我答得唔岩 但我覺得halogen concentration 唔同好易影響color change concentrated br2 你話可以turn orange diluted br2 turn to brown 但用silver nitrate 就好確實睇到preciptate

實際實驗的確會受濃度影響
但題目無given咁多因素相反亦都唔會要求你個答案假設太多野
Br2個reddish brown color明顯過Cl2既顏色好多
即使濃度低仍然好visible
至於prange定reddish brown定brown 無所謂的

2012MC考左 aspirin既active ingredient 既structural formula
我想問呢樣野宜家有無out-c到

2012MC考左 aspirin既active ingredient 既structural formula
我想問呢樣野宜家有無out-c到

aspirin個structure咋wor 咁難認得？
syl明文寫住要識aspirin structure同function的

2012MC考左 aspirin既active ingredient 既structural formula
我想問呢樣野宜家有無out-c到

aspirin個structure咋wor 咁難認得？
syl明文寫住要識aspirin structure同function的

中學雞唔識睇syllabus
諗住呢啲背書題唔會考

2012MC考左 aspirin既active ingredient 既structural formula
我想問呢樣野宜家有無out-c到

aspirin個structure咋wor 咁難認得？
syl明文寫住要識aspirin structure同function的

中學雞唔識睇syllabus
諗住呢啲背書題唔會考

其實有好多野要記 只係有好一部分喺你學既過程明左所以記得咁解

When a negatively charged rod is placed near a jet of liquid running out from a burette, the jet of liquid deflects towards the rod. What is the liquid?
Water, hexane, CHCl3

佢up mud spring呀

2012MC考左 aspirin既active ingredient 既structural formula
我想問呢樣野宜家有無out-c到

aspirin個structure咋wor 咁難認得？
syl明文寫住要識aspirin structure同function的

中學雞唔識睇syllabus
諗住呢啲背書題唔會考

其實有好多野要記 只係有好一部分喺你學既過程明左所以記得咁解

又好似係
睇黎睇翻書

When a negatively charged rod is placed near a jet of liquid running out from a burette, the jet of liquid deflects towards the rod. What is the liquid?
Water, hexane, CHCl3

佢up mud spring呀

polar molecule會respond to electric field 例如H2O

polar molecule要符合兩個條件
1. contain at least one polar bond
2. asymmetric in shape

H2O同CHCl3都係polar
hexane得C-C / C-H bond, all non polar

When a negatively charged rod is placed near a jet of liquid running out from a burette, the jet of liquid deflects towards the rod. What is the liquid?
Water, hexane, CHCl3

佢up mud spring呀

polar molecule會respond to electric field 例如H2O

polar molecule要符合兩個條件
1. contain at least one polar bond
2. asymmetric in shape

H2O同CHCl3都係polar
hexane得C-C / C-H bond, all non polar

原來係咁
未聽過