Qualification > Sciences
CHEMISTRY PAPER 1 HERE
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--- Quote from: aquarian93 on June 11, 2009, 02:42:13 pm ---this is from may 05, if anyone has solved it, pls help me.
for question 16, the answer is D
y cnt it b C? pls help, thanks in advance
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For 3, there would be no loss in mass, as any gas produced would remain inside the conical flask, and not be able to excape through the stopper.
nid404:
--- Quote from: madee on June 11, 2009, 10:03:50 am ---
--- Quote from: john12345 on June 10, 2009, 04:46:40 pm ---nd one more question
which process can convert molecules to a new substance by removing hydrogen atoms
A displacement
B fermentation
C neutralisation
D oxidation
how do you solve this question
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john it is oxidation By the way it is not der 4r us it cums in O-levels loss of hydrogen is oxidation
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Just didn't strike my mind...thanx for reminding and moreover for helping john :)
esso:
--- Quote from: nid404 on June 11, 2009, 02:43:09 pm ---
--- Quote from: esso on June 11, 2009, 02:34:49 pm ---An aqueous solution contains barium iodide.
It is possible to obtain a solution that contains Ba2+(aq) but no I–(aq) by adding ……1…… until no
more ……2…… precipitate forms.
Which words correctly complete gaps 1 and 2?
1 2
A aqueous lead(II) nitrate white
B aqueous lead(II) nitrate yellow
C dilute sulphuric acid white
D dilute sulphuric acid yellow
help please...need an explanation..
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U omit C and D first cuz if u want barium ions in the solution that reacting it with acid gives sulphate which is not soluble.
Since u want barium ions to be in the solution, u want iodide to precipitate so that it can be filtered. So u add Lead nitrate and this will react with barium iodide to give barium nitrate and lead iodide(which is yellow). lead iodide can be filtered as it is insoluble and will precipitate. the solution will contain no iodide ions.
I hope it's clear... :-\
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ya crystal clear...Thanks for d help...
dondon93:
Guys please help with this,...
When lithium reacts with water, if forms lithium oxide + hydrogen OR it forms lithium hydroxide + hydrogen????
And which metals react with water to form metal oxide + hydrogen and which ones react with water to form metal hydroxide + hydrogen???
Help please???
Bani:
Please help.....O/N 2007, paper 1, Q11
please explain, thanks in advance...
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