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標題: [Chem] 幾題chem問題,請幫幫手 [打印本頁]

作者: imnotok    時間: 2010-4-25 03:59 PM     標題: 幾題chem問題,請幫幫手

03 MC 9
metal,ionic compound,covalent compound
佢地既melting point邊個最高?邊個最低?
ammonia solution/aqeuous ammonia係reaction時該寫nh3(aq)定nh4+(aq) + oh-(aq)?
thank you.......
作者: 桃子    時間: 2010-4-25 04:05 PM

>>metal,ionic compound,covalent compound
>>佢地既melting point邊個最高?邊個最低?

Molecules have the lower melting point than giant structures.
That's all you need to know.

>>ammonia solution/aqeuous ammonia係reaction時該寫nh3(aq)定nh4+(aq) + oh-(aq)?
Reactant side:
NH3(aq) is the best.
OH-(aq) is also acceptable.

Product side:
NH4+(aq), if soluble
Formula of ammonium salt, if insoluble
作者: lts531    時間: 2010-4-25 04:17 PM

>>03 MC 9
可能因為carbon 係chemically inert 所以好少會corrode(或者好慢)
而copper會corrode快d 所以iron 代替copper lose electrons都快d

作者: lts531    時間: 2010-4-25 04:22 PM     標題: 回覆 #2 桃子 的帖子

咁我想問 NH3(aq)同 acids(solution) react會唔會出水?
作者: 桃子    時間: 2010-4-25 04:58 PM     標題: 回覆 #4 lts531 的帖子


NH3 + HX --> NH4X
NH3 + H2X --> (NH4)2X
作者: lts531    時間: 2010-4-25 05:10 PM

作者: 桃子    時間: 2010-4-25 06:05 PM     標題: 回覆 #6 lts531 的帖子


Just forget about those silly definitions used by some publishers.
You won't be ask to give a definition of neutralization/acid-base reaction in HKCEE and there are many many many acid-base reactions that do not give salt and water as the only products.
作者: imnotok    時間: 2010-4-28 01:47 AM

thx 4 the above answering,but i want an accurate explanation for 03 #9..
thank you
作者: 341824600    時間: 2010-4-28 01:51 AM     標題: 回覆 #8 imnotok 的帖子

haha...just done that..i take ce too tmr~

explaination:  iron connect to less reactive metal will promote rusting~

so only ans isb

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