3boys2girls » 化學物理生物 » For CE chem Acid(little revision)

2009-3-22 16:16 ZeroYip
For CE chem Acid(little revision)

[size=4]Just for little concept for F4-5 student chemistry about acid
Some of my friends asked me this question again and again
They ask me that what is this reaction mean
H2SO4(aq)+H2O(l)<>H3O+(aq) +HSO4-(aq)………….1
For reaction 1 it is H2SO4(aq) dissolve in water and it will ionized into hydroium ion and HSO4- ion.
And the hydroium ion is the strongest acidic ion which can exist in the water.
So the reaction go reverse.
In my mind for CE you just need to remember the six strongest acid:
Hydrochloric acid:  HCl
Hydrobromic acid:  HBr
Hydroiodic acdi:  HI
sulfuric acid:  H2SO4
Nitric acid:  HNO3
Perchloric acid:  HClO4
These strong acid will have reverse reaction when they put into water.
P.S. if they are in crystal form (s) they don’t have any reaction.
They will have reaction if and only if they are in (aq).

I think in CE level acid will only react with the follow stuff
[color=Red]1) Carbonates[/color]
[color=SandyBrown]2) Hydrogencarbonates[/color]
[color=YellowGreen]3) Metal Oxide[/color]
[color=SeaGreen]4) Metal Hydroxide[/color]
[color=MediumTurquoise]5) Metal[/color]

For Carbonates

Na2CO3(aq)+ H2SO4(aq)>Na2SO4(aq)+CO2(g)+H2O(l)
Ionic equation will be
(CO3)2-(aq)+2H+>CO2(g)+H2O(l)

For any insoluble carbonate
CaCO3(aq)+2HNO3(aq)>Ca(NO)2(aq)+CO2(g)+H2O(l)
Ionic equation will be
CaCO3(s)+2H+(aq)>Ca2+(aq)+CO2(g)+H2O(l)

For Hydrogencarbonates

NaHCO3(aq)+HCl(aq)>NaCl(aq)+CO2(g)+H2O(l)
Net ionic equation: HCO3-(aq)+H+(aq)>CO2(g)+H2O(l)

For metal oxide
For soluble oxide
Na2O(aq)+2HCl(aq)>2NaCl(aq)+H2O(l)
Ion equation: O2-(aq)+2H+(aq)>H2O(l)
P.S. heat will evolved

For insoluble oxide
CuO(s)+2HCl(aq)>CuCl2(aq)+H2O(l)
Ionic equation: CuO(s)+ 2H+(aq)> Cu2+(aq)+H2O(l)


For Metal Hydroxide
For soluble hydroxide
NaOH(aq)+HCl(aq)>NaCl(aq)+H2O(;)
Ionic equation: OH-(aq)+H+(aq)>H2O(l)
For insoluble hydroxide
Zn(OH)2(s)+2HNO3(aq)>Zn(NO3)2(aq)+2H2O(l)
Ionic equation: Zn(OH)2(s)+2H+(aq)>Zn2+(aq)+2H2O(l)

For metal
Ca(s)+2HCl(aq)>CaCl2(aq)+H2(g)
Only the metal for K Na Ca Mg Al Zn Fe Pb can react will dilute acid

For concentrated acid
Like H2SO4

Cu(s)+SO4 2-(aq)+4H+(aq)> Cu2+(aq)+SO2(g)+2H2O(l)

HNO3

Cu(s)+ 2NO3-(aq)+4H_(aq)>Cu2+(aq)+2NO2(g)+4H2O(l)[/size]

[size=4]
let me know when i get it wrong
it is nearly 3:00am in USA now
so sleepy when im typing[/size]

[[i] 本帖最後由 ZeroYip 於 2009-3-22 16:21 編輯 [/i]]

2009-4-20 13:17 m!mosa
有無中文?-_-

2009-4-20 13:51 ZeroYip
有人可以translate?
不如你講你既問題

2009-4-22 15:15 a902355
[align=left][color=#0e00a0]CAco3->CaO+CO2
要生成960cm3的二氧化碳(在常溫常壓下)需要多少質量的碳酸鈣?
(相對原子質量:O=16.0,Cu=63.5;在常溫常壓下,氣體的摩爾體積=24.0dm3mol-1
[b]Ans:[/b][/color][/align]

2009-4-22 16:11 ZeroYip
i hope you don;t mind i use english to answer ur question

(960cm^3CO2)(1mol/24.0dm^3)(1dm^3/1000cm^3)(1cm^3/1g)(44gCO2/1mol CO2)(1mol CO2/1 mol CaCO3)(1mol CaCO3/100gCaCO3)=0.0176g CaCO3
P.S. Cu=63.5 but question is Ca=.="

2009-4-22 18:19 a902355
[font=Dotum][color=navy]簡單分子結構同巨型離子結構點分(?)[/color][/font]

2009-4-23 00:10 ZeroYip
簡單分子結構
簡單分子結構是分子之間藉着微弱的范德華引力排列所形成的結構
it is only the structure for molecular

巨型離子結構
巨型離子結構是離子化合物內陽離子和陰離子整齊相間地排列所形成結構
it is the structure for anion and cation when they mix together

2009-4-23 13:50 a902355
[color=navy][font=Dotum]釩的符號V.在NH4VO3中,釩的氧化數是多少(?)點計
咩係單原子分子?-_-[/font][/color]

2009-4-24 05:17 ZeroYip
please reopen a new topic ok?
i can explain a little longer in that one
ty

2009-4-24 13:59 ZeroYip
NH4 係當+1
O係-2
so V係 +1+3(-2)+v=0
v=5
氧化數係+5

单原子分子就是只有一个原子构成的分子
好似group 8 佢地就係单原子分子

2009-4-27 22:17 sdfantasy
In CE level, you just need to memorize 3 of strong acids,

Hydrochloric acid, Sulphuric acid and Nitric acid.

And some weak acids,eg: alkanoic acid

In Ce level, when aqueous sulphuric acid is dissolved in water,

complete ionization occurs,The acid will be ionized yo give Hydrogen ions and Sulphate ions

The equation of the reaction mentioned above:

H2SO4(aq) + water -> 2H+  + SO4^2-

[[i] 本帖最後由 sdfantasy 於 2009-4-27 22:20 編輯 [/i]]

2009-4-28 10:19 ZeroYip
O man?
3 strong acid only?
I don't know sry.
anyway i will go back HK to take the CE level and Al level of chemistry to see what grade I can get
where can i go to apply for that?

2009-4-28 15:35 sdfantasy
You can go to HKEAA to apply for that..

ya, 3 strong acid only

2009-4-28 21:50 magiyafeimo
[quote]原帖由 [i]sdfantasy[/i] 於 2009-4-28 15:35 發表 [url=http://www.3boys2girls.com/redirect.php?goto=findpost&pid=38485804&ptid=589755][img]http://www.3boys2girls.com/images/common/back.gif[/img][/url]
You can go to HKEAA to apply for that..

ya, 3 strong acid only [/quote]

請留意三種acid既唔同molarity會造成唔同效果

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