Debrief -> Science Chemistry!
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Discuss the questions here!
For Science Chemistry
Paper 5152/03 and 5154/03 -
open already ah? I was thinking how strange for a mod to lock his own thread after the opening post
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grrr GG liao.
ammonia + water -> aqueous ammonia
the equation i dunnoe how to write.
simi oxygen welding...oso dunnoe.
hydrogen chloride dissolves in water, equation oso dunnoe
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NH3(g) + H2O(l) --> NH4OH(aq)Originally posted by Y_Shun:grrr GG liao.
ammonia + water -> aqueous ammonia
the equation i dunnoe how to write.
simi oxygen welding...oso dunnoe.
hydrogen chloride dissolves in water, equation oso dunnoe
Hydrogen Chloride dissolves in water to gives Hydrochloric acid. -
i din know aqeous ammonia is NH4(OH)... !!!!!!!!!!!!!!
wasted =[
all those weid werid qtns come out wf. -
ya loh.. sian liao lah... alot of question come out on topic : metals .. i only study reactivity series and burst furnace on that topic only..... siao liao la... no more As for me
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Share some of the questions which you don't know. We can help you figure out.
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careless.
btw, the school never return us A MATH PAPAER 2
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You must request from the Chief Presidenting Examiner.Originally posted by Y_Shun:careless.
btw, the school never return us A MATH PAPAER 2 -
OKay this time round, the chemicals seem to be all colourless. I remember during my O level chem practical, i just need to observe what color/gas other pple are getting, then i analyse the questions and plus my chemicals...i know the answer liao
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lol who is that?Originally posted by Darkness_hacker99:You must request from the Chief Presidenting Examiner.
dunno rah....they say can get it frm school office. we go get they say haven't 24 hrs blah blha blha...then nobody care liao. -
Lame la..most of the topics that came out i never study properly or never study at all..
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wooooooooooot
marcromolcules my death chapter neva come out...MCQ coming out for sure -
Wah riaos. Pwned hard hard.
This paper more of thinking required.
GG. -
LAST QTN.
It ask whats the reactions rubidium with water.
Do we just say cold water? or oso with steam -
Take it as cold water, unless it specify steam.Originally posted by Y_Shun:LAST QTN.
It ask whats the reactions rubidium with water.
Do we just say cold water? or oso with steam
2Rb(s) + 2H2O(l) --> 2RbOH(aq) + H2(g) -
Originally posted by Darkness_hacker99:Hydrogen Chloride dissolves in water to gives Hydrochloric acid.
I wrote:
HCl + H2O --> H2O2 + Cl2 + H2
I balanced in test paper. But not gona balanced here.
I wiki-ed, H2O2, hydrogen peroxide is weak acid. Cl2, to the right of the periodic table, also acid. I think. Not sure. -
you wiki liao....still dunno the answer? H2O2 not so easily produced.Originally posted by zanemiller:
I wrote:
HCl + H2O --> H2O2 + Cl2 + H2
I balanced in test paper. But not gona balanced here.
I wiki-ed, H2O2, hydrogen peroxide is weak acid. Cl2, to the right of the periodic table, also acid. I think. Not sure.
HCl is very soluble in water (and in other polar solvents).
Upon contact, H2O and HCl combine to form hydronium cations H3O+ and chloride anions Cl- through a reversible chemical reaction:
HCl + H2O Â�¨ H3O+ + Cl−
http://en.wikipedia.org/wiki/Hydrogen_chloride -
Firstly, I don't think that HCl + H2O will produce Hydrogen Peroxide. Cl2 is Chlorine gas, which is found at group VII of the periodic table.Originally posted by zanemiller:
I wrote:
HCl + H2O --> H2O2 + Cl2 + H2
I balanced in test paper. But not gona balanced here.
I wiki-ed, H2O2, hydrogen peroxide is weak acid. Cl2, to the right of the periodic table, also acid. I think. Not sure.
I still believe that the product is Hydrochloric acid.
As for why is the solution acidic, the correct answer I supposed. is because of the presence of Hydrogen ion.
The front statement "...to form an acidic solution..." acts as a smokescreen, but it's actually testing you on the knowledge of what gives acids it's property.
For this case, it's because of the Hydrogen ions. -
Hydronium cation H3O+ is not under O level syllabus.Originally posted by HyuugaNeji:you wiki liao....still dunno the answer? H2O2 not so easily produced.
HCl is very soluble in water (and in other polar solvents).
Upon contact, H2O and HCl combine to form hydronium cations H3O+ and chloride anions Cl- through a reversible chemical reaction:
HCl + H2O Â�¨ H3O+ + Cl−
http://en.wikipedia.org/wiki/Hydrogen_chloride
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NH4(OH) <-- No need bracket.Originally posted by Y_Shun:i din know aqeous ammonia is NH4(OH)... !!!!!!!!!!!!!!
wasted =[
all those weid werid qtns come out wf. -
lucky they never say want equations...if not i gg.Originally posted by Darkness_hacker99:Take it as cold water, unless it specify steam.
2Rb(s) + 2H2O(l) --> 2RbOH(aq) + H2(g)
but i only say it produces rubidium hydroxide....
hmm then i wrote the reaction with oxide incase. -
H2O2 is a lewis acid but HCl is a strong Bronsted acid.Originally posted by zanemiller:
I wrote:
HCl + H2O --> H2O2 + Cl2 + H2
I balanced in test paper. But not gona balanced here.
I wiki-ed, H2O2, hydrogen peroxide is weak acid. Cl2, to the right of the periodic table, also acid. I think. Not sure.
In your question, it is assumed that the term acid refers to Bronsted acid.
You think too much... too complicated -
so how?!?! I not really sure how well I did. Haisss... I just hope that 70%+ gurantee A2. Anyone who has friends who did very well?
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me took the paper too.
lost much marks on mole question, and the hydrogen chloride question too.
and i wrote ammonia + water -> ammonium hydroxide
why molten state ionic compound can conduct electricity?
i wanted to write the txtbk says so, but dint lah
made a wild guess that electricity can pass through the spaces the ions have between them..
haiz, section B was rather easy though