Additional Questions for QA
Yoz,
To help you in your revision for the OBA, here's two problems for you.
You can discuss the answers by posting comments. =)
To help you in your revision for the OBA, here's two problems for you.
You can discuss the answers by posting comments. =)
Labels: Extra Questions, QA
posted by Potassium Hydroxide | 4:05 PM
10 Comments:
question 1
a) A - zinc carbonate
B - carbon dioxide
C - aqueous zinc sulphate
D - zinc hydroxide
E - lead(II) sulphate
F - barium sulphate
b) bubble the gas into limewater. carbon dioxide would give a white precipitate with limewater.
c) Zn2+ + 2OH- = Zn(OH)2
d) heat and collect residue, dry residue with filter paper?
is this correct?
What do others think?
Btw, for part d, it is asking for the reagents and steps that are needed to make the salt.
ok so for d can i use sulphuric acid and zinc metal? addition of excess solid to acid. anyway this prob come in too late lol..
oh yah A shud be just zinc i dint see the metal A part -.- i a bit stuck at qn 2 but i trying to do other work lol.. trying v hard (:
my name is zhu yi.
Yup, substance A must be Zn metal.
The rest of rockingaway's answers are rite! Well done. U rawks!
so, B is hydrogen? if that's the case, then to verify it. i'll have to use a lighted splinter and test it with the gas?
Yup, Shawn is rite to point out that the gas B is H2. Oversight on my part.
For Q2,
White ppt V should be Ca(OH)2 right? NaOH, alone, is a test for cation and the only cation insoluble in excess and forms a white ppt is Ca2+, right?
Gas W should be ammonia NH3 as that's the only basic gas that we all know so far... right?
Adding Al and warming is a test for nitrate NO3 - right? So that means that NO3 - is present in solution R, right? (Can it be NH4 +?)
For white ppt S, it should be an insoluble chloride salt, right? So it must be either AgCl or PbCl2 right?
After that... I am lost.
Oh, temple, I seek explanations.
Other devotees, please comment.
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