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ALL CIE CHEMISTRY DOUBTS HERE !!
$H00t!N& $t@r:
--- Quote from: Vin on April 28, 2011, 08:09:50 pm ---Can you please post the paper?
--- End quote ---
Here it is: http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9701%20-%20Chemistry/9701_w10_qp_23.pdf
Vin:
2 H2S + 3O2 -> 2SO2 + 2H2O
Let oxi. no. of S be x
H2S => +2 + x = 0
sum of all oxidation states of atoms 0
so x = -2
SO2 => x + 2(-2)
x = +4
S => for any atom its 0
SO2 is reduced from +4 to 0
^This is what I did when i first saw the ques. After checking the ms I read the question again, however it clearly says "the oxidation numbers of each of the sulfur-containing substances in this reaction? "
which should be 0
and not oxi. no. of Sulfur in these compounds :/ If you get what I mean.
Sorry to complicate things all over again, I'm confused myself. Lets wait for someone smarter to conform
$H00t!N& $t@r:
--- Quote from: Vin on April 28, 2011, 09:03:09 pm ---2 H2S + 3O2 -> 2SO2 + 2H2O
Let oxi. no. of S be x
H2S => +2 + x = 0
sum of all oxidation states of atoms 0
so x = -2
SO2 => x + 2(-2)
x = +4
S => for any atom its 0
SO2 is reduced from +4 to 0
^This is what I did when i first saw the ques. After checking the ms I read the question again, however it clearly says "the oxidation numbers of each of the sulfur-containing substances in this reaction? "
which should be 0
and not oxi. no. of Sulfur in these compounds :/ If you get what I mean.
Sorry to complicate things all over again, I'm confused myself. Lets wait for someone smarter to conform
--- End quote ---
I understand what you mean... they want us to find out the oxidation number for the element attached to sulphur and not sulphur itself, but I thought that the oxidation number for S is -2 cuz it's right below oxygen.. :-\ and for the second one, SO2, why did you find the oxidation number for sulphur and not oxygen, the way you did for the first one, H2S... the last one was pretty simple :)
Sue T:
i have a ques from paper 41 mj 10
3(c) The molecule dichlorocarbene, CCl2, can be produced under certain conditions. It is
highly unstable, reacting with water to produce carbon monoxide and a strongly acidic
solution.
(i) Suggest the electron arrangement in CCl2 and draw a dot-and-cross diagram
showing this. Predict the shape of the molecule.
th answer was
.. ..
Cl:C:Cl or Cl=C–Cl
+ –
bent or non-linear or angle = 100–140o
how do we arrive at this structure????
Amelia:
--- Quote from: Sue T on April 30, 2011, 04:53:38 pm ---i have a ques from paper 41 mj 10
3(c) The molecule dichlorocarbene, CCl2, can be produced under certain conditions. It is
highly unstable, reacting with water to produce carbon monoxide and a strongly acidic
solution.
(i) Suggest the electron arrangement in CCl2 and draw a dot-and-cross diagram
showing this. Predict the shape of the molecule.
th answer was
.. ..
Cl:C:Cl or Cl=C–Cl
+ –
bent or non-linear or angle = 100–140o
how do we arrive at this structure????
--- End quote ---
One lone pair, two bond pairs. Repulsion between lone pairs and bond pairs.
http://upload.wikimedia.org/wikipedia/commons/8/8c/Dichlorocarbene-from-MW-2001-2D.png
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