equation 等等的問題 . . 新增 phy

小霞的fans

a coin is made of two metals. when the coin was added to excess dilute hydrochloric acid,
a pale green solutionXwas formed and a colourless gasYwas evolved. some brown solids
Zwere also found at the bottom of the pale green solution. the resulting mixture was then filtered to
remove  the brown solidsZ.when an excess of sodium hydroxide solution was added to the filtrate,
a green precipitateWwas formed.

問X,Y,W,Z 係咩 ?　X 係 IRON(II) CHLORIDE , Y係HYDROGEN GAS, W係IRON(II) HYDROXIDE , Z 係COPPER .. 岩嗎 ?

又好似錯 ..

第2題:

Write abalanced equationfor the reaction involved.

adding ammonia solution to zinc sulphate solution until in excess.

我始終都唔係唔明ammonia solution 既FORMULA應該係NH3定係 NH4^+ + OH^- ,,其實應該係邊個 . .

而且唔係IONIC EQUATION .. 唔識寫>< HELP ME ..

新增一條PHY .

A LUMP OF PLASTICINE OF MASS 0.2kg is hanging freely in air form a string.a bullet of mass 0.1 kg is fired from an air gun.it hits the plasticine then swings to a maxium height of 0.06m abive it's initial position.

a. find the speed of the plasticine immediately after the bullet is embedded in it .
佢乜野 velocity都冇比點計= =  ..

b. hong kong ordinance states that the kinetic energy of bullets fired from air huns should not exceed 2j . ny considerinh the speed of the bullet before it hits the plasticine, explain why the above gun violates the ordinance .

我唔識粒子彈既velocity ><

[ 本帖最後由 小霞的fans 於 11/3/2009 09:17 PM 編輯 ]

雪貓

原帖由 小霞的fans 於 12/3/2009 04:19 PM 發表

                               
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a coin is made of two metals. when the coin was added to excess dilute hydrochloric acid,
a pale green solutionXwas formed and a colourless gasYwas evolved. some brown solids
Zwere also found at the bottom of the pale green solution. the resulting mixture was then filtered to
remove  the brown solidsZ.when an excess of sodium hydroxide solution was added to the filtrate,
a green precipitateWwas formed.

問X,Y,W,Z 係咩 ?　X 係 IRON(II) CHLORIDE , Y係HYDROGEN GAS, W係IRON(II) HYDROXIDE , Z 係COPPER .. 岩嗎 ?

又好似錯 ..

第2題:

Write abalanced equationfor the reaction involved.

adding ammonia solution to zinc sulphate solution until in excess.

我始終都唔係唔明ammonia solution 既FORMULA應該係NH3定係 NH4^+ + OH^- ,,其實應該係邊個 . .

而且唔係IONIC EQUATION .. 唔識寫>< HELP ME ..

應該沒錯..?
你要的eqt是指哪個~____~?如果是↓
when the coin was added to excess dilute hydrochloric acid,
2HCl+Fe → FeCl2+H2
ammonia sol可以寫是NH3/NH4OH都可以的吧?
因它不是completely ionized,即是在sol中有ions也有NH3
但平時如是要求寫neut的eqt本人就多選寫 NH4OH因為一看就知道XDD但其實分別不大..

ce的東西可能會有錯漏太久沒接觸-0-

[ 本帖最後由 雪貓 於 12/3/2009 06:44 PM 編輯 ]

abc666

phy
a.use 1/2mv^2=Mgh

b.KE=1/2mv^2

larger than 2J--> violates  the ordinance
----------------------------------
CHEM ammonia

NH3 slightly ionized in water
NH3  + H2O  --  >  NH4+ + OH-
不同情況用不同的
ammonia solution to zinc sulphate until in excess
是OH-和Zn react
2OH- + ZnSO4  --> Zn(OH)2  + SO42-
Zn(OH)2-->white ppt
excess的話,是NH3 react with Zn(OH)2
所以redesolve

[ 本帖最後由 abc666 於 12/3/2009 10:50 PM 編輯 ]

fish

原帖由 abc666 於 12/3/2009 20:06 發表

                               
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excess的話,是NH3 react with Zn(OH)2
所以redesolve,不過這equation ce應該不用考的

要考的....CE syllabus尾二那一項有寫-w-

final product 的 formula是下面的這個....自己試試balance一下吧=]
[Zn(NH3)4]2+
為何會form就過了CE才學吧

要知的ammonium complex還有 copper的 [Cu(NH3)4]2+
silver那個syllabus上沒寫,但我當年有教 [Ag(NH3)2]+

abc666

原帖由 fish 於 12/3/2009 09:27 PM 發表

                               
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要考的....CE syllabus尾二那一項有寫-w-

final product 的 formula是下面的這個....自己試試balance一下吧=]
[Zn(NH3)4]2+
為何會form就過了CE才學吧

要知的ammonium complex還有 copper的 [Cu(NH3)4]2 ...

對不起,不太清楚,不記得了
我好像ce從來未讀過-.-

p.s.謝魚

fish

原帖由 abc666 於 12/3/2009 22:49 發表

                               
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對不起,不太清楚,不記得了
我好像ce從來未讀過-.-

p.s.謝魚

我當時用的書將這些東東放在最後的一課中(那課的形式還要是summary) 且半頁都不佔不了.....老師不做將excess NH3倒入CuSO4我也不會留意到wwww
我甚至想過有不少學校會不教這東東

我記得對CE可能有用的coordinate compound有以下的:

Rusting Agent or potassium hexacyanoferrate(III) - K3[Fe(CN)6]   (雖然它亦含 phenolphthalein -w-)
[Al(OH)4]- (excess hydroxide added to Al3+) (colorless)
[Zn(OH)4]2- (excess hydroxide added to Zn2+) (colorless)

[Cu(NH3)4]2+ (excess NH3) (deep blue)
[Zn(NH3)4]2+  (excess NH3) (colorless)

面對 compound identification的問題時又不能用flame test/ precipitation test 作答的話時可用這些東東

我用的書還有多2個 syllabus上貌似沒要求的
[Pb(OH)4]2- (excess hydroxide added to Pb2+)
[Ag(NH3)2]+ (excess NH3)

[ 本帖最後由 fish 於 13/3/2009 02:24 AM 編輯 ]

超夢夢的夢境

原帖由 fish 於 13/3/2009 02:22 AM 發表

                               
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我當時用的書將這些東東放在最後的一課中(那課的形式還要是summary) 且半頁都不佔不了.....老師不做將excess NH3倒入CuSO4我也不會留意到wwww
我甚至想過有不少學校會不教這東東

我記得對CE可能有用的coordina ...

亂入
魚大用書的是Aristo出的嗎?
CE肯定有教excessive啊,而且不僅是excessive NH3,還有excessive NaOH呢
那個soluble/insoluble的表,我還花時間去記www

fish

原帖由 超夢夢的夢境 於 13/3/2009 12:37 發表

                               
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亂入
魚大用書的是Aristo出的嗎?
CE肯定有教excessive啊,而且不僅是excessive NH3,還有excessive NaOH呢
那個soluble/insoluble的表,我還花時間去記www

在網上找了一下Aristo Chem的封面，我想應該是這本了
我校當然有教啊...但出版商只將它放在Chpater 39(?) (Identification of compounds)而不放在說Precipitation Reaction (16?)的那課令我有點不爽-w-

現在樓主留意到及知道要考的相關就好了-w-

Ivanhy92

原帖由 fish 於 13-3-2009 22:31 發表

                               
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在網上找了一下Aristo Chem的封面，我想應該是這本了
我校當然有教啊...但出版商只將它放在Chpater 39(?) (Identification of compounds)而不放在說Precipitation Reaction (16?)的那課令我有點不爽-w-

現在 ...

Aristo入面d內容好散...

小霞的fans

原帖由 abc666 於 12/3/2009 12:06 AM 發表

                               
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phy
a.use 1/2mv^2=Mgh

b.KE=1/2mv^2

larger than 2J--> violates  the ordinance
----------------------------------
CHEM ammonia

NH3 slightly ionized in water
NH3  + H2O  --  >  NH4+ + OH-
...

其實我唔知A 點解係p.e.=k.e.  
可以解釋一下嗎>< thx!