Qualification > Sciences
IG Chemistry Paper 3 discussion
horror:
--- Quote from: Shogun on June 02, 2009, 07:18:15 pm ---it wasnt OH in tht fe thing it was some halogen i think, im100% sure it wasnt OH in the fill in the blanks stuff for tht ionic reaction. however ure explaination is good.
--- End quote ---
Trust me man K2PO4 is right otherwise my teacher and a couple of A* students are wrong :) it was a tough question though xD
bibo the wa7sh:
--- Quote from: ManaH on June 02, 2009, 08:01:59 pm ---
--- Quote from: notty_me on June 02, 2009, 04:15:44 pm ---
--- Quote from: bibo the wa7sh on June 02, 2009, 04:03:35 pm ---heY everYone,
wat about electrolysis of dilute sodium chloride???
Cathode..........
anode..............
and wat happens to the electrolyte???.....
WaiTinG 4 uR RepLies!!xD!!
--- End quote ---
at da cathode it was h2
at anode it was o2
so conc. NaCl was left
--- End quote ---
NOPE its was concentrated NaCl
therefore @ anode Cl would be depsoed no O2
--- End quote ---
um totally sure it was DILUTE aqueos sodium chloride because i saw the test after we did it by 1 day(24 hours!!) from our teacher in sKewL!!!xD!! ;D
Shogun:
--- Quote from: bibo the wa7sh on June 03, 2009, 09:54:27 am ---
--- Quote from: ManaH on June 02, 2009, 08:01:59 pm ---
--- Quote from: notty_me on June 02, 2009, 04:15:44 pm ---
--- Quote from: bibo the wa7sh on June 02, 2009, 04:03:35 pm ---heY everYone,
wat about electrolysis of dilute sodium chloride???
Cathode..........
anode..............
and wat happens to the electrolyte???.....
WaiTinG 4 uR RepLies!!xD!!
--- End quote ---
at da cathode it was h2
at anode it was o2
so conc. NaCl was left
--- End quote ---
NOPE its was concentrated NaCl
therefore @ anode Cl would be depsoed no O2
--- End quote ---
um totally sure it was DILUTE aqueos sodium chloride because i saw the test after we did it by 1 day(24 hours!!) from our teacher in sKewL!!!xD!! ;D
--- End quote ---
yup it was dilute..
Kim243:
Guys there are a few questions i wanted to make sure that they are correct
1-heat the solution--> i wrote to seperate crystals from water
2-what type of organic compound has the following linkage--->polyester
3-the complete question an alchohol group and an acid group (didnt write organic before acid:/)
4-advantages -->biodegradable so it wont cause pollution
5-water behaves as a base-->cuz its a proton acceptor
6- for the equation between sodium flouride and calcium chloride why was double the volume of NaF added?-->i wrote cuz 1 mole of CaCl2 reacts with 2 moles of NaF
7-condensation or addition? condensation cuz water was removed from the monomer
8-the stronger acid was HCl cuz it was 97% ionized
9-ph of HCl will be lower than the other acid (Or do i have to write values)?
10-for the raw materials i wrote -->fractional distillation of liquified air and cracking of an alkane (didnt notice that the process wasnt required)
11-the moles 0.07 same as silicon?and could somebody plz explain which one is limiting and why?
12-for the T formula i got the formula wrong but i wrote the volume of phosphate solution is double the volume of metal T nitrate solution for the explanation
13-for the exothermic reaction i got the values of reactants and products and checked which has greater value
I know the q's are too many but im kinda freaked out cuz i did very badly in the exam
robot_avenger:
--- Quote from: .... on June 02, 2009, 07:15:21 pm ---what i think was that the value of the height had nothing to do with the volume, since height was in mm, and volume in cm3. I just remember that, 18 cm3 of aqueous nitrate of T, reacted with 2 cm3 portions of a solution of Na3PO4. The maximum precipitate of the phosphate of T, was reached at 6 cm3 of sodium phosphate. Since both had the same concentration, it didnt really matter, the main thing that mattered was the volume then. Now, we have that the volume of the nitrate of T used was 18, and that of the sodium phosphate was 6. so volume ratio of the nitrate reactant to the phosphate reactant is 18:6 = 3:1, which is also the mole ratio. So if we construct an ionic equation using the mole ratio, we can get ...
PO43- + 3T+ ----> T3PO4
when i came home, i opened june 2004 paper 3, of chem, where i remember seeing a similar graph as the one given in the question..
in the june 2004 q, 4 cm3 of aqueous iron (III) chloride, reacts with 2cm^3 portions of aqueous sodium hydroxide..according to the graph..the maximum volume of sodium hydroxide at which the maximum precipitate is formed, is at 12 cm^3..
thus the volume ratio of the chloride reactant to the hydroxide, is 4:12 = 1:3
That means, there will be one Fe3+ ion for every 3 OH- ions..according to the ratio..
the next part of the given is..complete the following reaction..
Fe3+ + .....OH- -----> ...........
since ratio is 1:3..itll be 3 OH- forms Fe(OH)2..
the concentration of both reactants is 1moldm-3 which is given..
so the questions are quite similar..and so, i think T3PO4
i dont consider myself a genius, just mixxing familiar stuff with unfamiliar stuff.
--- End quote ---
Dude I love You!!
I used exact same reasoning!!!!!
Atleast now i know i used valid reasoning!!
Thank you!
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