[DSE化學2019]同學準備好DSE CHEM未?

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153 Like 27 Dislike
2018-11-26 11:27:46
想問electrolysis 個到
如果 Br-嘅比人oxidized 咁個observation 應該寫brown colour appears around anode 定係直接寫brown gas evlove 左出黎.
2018-11-26 14:19:50
唔會有反應啊 NH3係alkaline 同CaO都唔會有
就係drying agent唔可以同reactant有reaction先用
2018-11-26 14:46:09
Equilibrium constant永遠唔計concentration of H2O
2018-11-26 15:04:56
chem 拎咩
2018-11-26 15:46:32
remove soluble impurities
隻salt本身唔溶咪用水沖
隻salt溶得既就rinse with small amount of cold distill water 但洗呢個工序唔少得

metal / halogen都係displacement
2018-11-26 15:50:13
yes 如果H2O本身喺system個量同其他species差唔多時就要計埋
唔計H2O既情況 係因為當H2O個量比人高超級左 變左佢個change可以當係constant
concept上黎講 constant既野係執曬入Kc值度
2018-11-26 15:53:47
唔包H2O 但正常唔會咁做 因為esterification本第tield已經低 再喺多H2O既環境做會更差

第二個都唔包
2018-11-26 15:58:44
因為上述個反應小到無咁滯 個影響好細
一般甚至當no reaction
2018-11-26 16:00:12
yes molten有heating出Br2(g)
就咁solution出Br2(aq)
2018-11-26 16:11:20
就算出H2O 都唔係當變左aqueous system咁計
因為acid同ethanol仲多 佢地先係solvent of the system

叫得你唔計H2O個case一定H2O會多人n倍(as solvent時, H2O = 55.56M)

solid溶左落水果d先計濃度 未溶既solid屬於constant concentration唔計
2018-11-26 16:17:36
你本身開頭無水既話個system點行
2018-11-26 16:22:35
正常你個system都要有solvent去運作
當你燒溶左A B 咁佢地咪互做solvent miscible大家
都有得計濃度 真係完全唔soluble果d先唔計
2018-11-26 17:11:30
計Kc要計concentration of H2O?
2018-11-26 17:12:32
咁又真係大把case要計既
esterification果d咪要
2018-11-26 18:45:14
Reaction between metal and steam ,
Al react with H2O(g) , 入面d Al 唔會 react 到係因為面到層 Al2O3 prevent further reaction ?
2018-11-26 18:46:39
yes
2018-11-26 18:54:39
係 所以令佢難同O2 / H2O react (唔連你remove左層oxide)
2018-11-26 18:59:27
Ching quit U?
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