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 ]

Ivanhy92

原帖由 sapphire 於 15-3-2009 00:10 發表

                               
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Conservation of Energy不只是在free falling才能用到吧
像一個swinging pendulum, 和free falling沒有關係, 但只要沒有energy loss to the surrounding, conservation of energy就能用上

你那條問題好像是CE  ...

原帖由 超夢夢的夢境 於 15-3-2009 20:20 發表

                               
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明顯有 Power input 嘛(茶)
conserveation of energy 只要沒 energy lost/power input/output 就能用~

謝謝上面兩位,怪不得之前既Mock抄了...

超夢夢的夢境

[quote]原帖由 arararchchch 於 14/3/2009 11:34 PM 發表

                               
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補充:只有Free falling先

sapphire

[quote]原帖由 arararchchch 於 14/3/2009 11:34 PM 發表

                               
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補充:只有Free falling先

Ivanhy92

原帖由 sapphire 於 14-3-2009 13:57 發表

                               
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Conservation of Energy, the kinetic energy of the bullet becomes the potential energy of the bullet and plasticine.
K.E. loss = P.E. gain

Normally, energy loss (e.g. sound, heat) will not be con ...

補充:只有Free falling先

sapphire

原帖由 小霞的fans 於 14/3/2009 01:15 PM 發表

                               
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其實我唔知A 點解係p.e.=k.e.  
可以解釋一下嗎>< thx!

Conservation of Energy, the kinetic energy of the bullet becomes the potential energy of the bullet and plasticine.
K.E. loss = P.E. gain

Normally, energy loss (e.g. sound, heat) will not be considered in this kind of question in CE level.

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!

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...

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-

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