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Author Topic: Edexcel CHEMISTRY DOUBTS!!!!  (Read 261771 times)

Offline Saladin

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #15 on: May 10, 2010, 09:09:12 am »
Quote from: damlaj on May 10, 2010, 09:05:17 am
Summer don't confuse the guy i'll tell you the right answer

sulphuric acid is a stong enough oxidising agent so a concentrated sulphuric acid couldn't be used because it will further get reduced it self and will oxidise the halide ion to form iodine or bromine resulting in now HI or HBr for the reaction with alcohol to form haloalakane.

You guys are wrong.

You see, the Bromine and Iodine ions are very powerful reducing agennts compared to that of Chlorine, and would result in further reactions, that would not form other products. http://www.chemguide.co.uk/inorganic/group7/halideions.html#top. This site will help u understand the whole thing.
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Offline Uchia

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #16 on: May 10, 2010, 09:26:19 am »
lol mysterious i said the same thing but in the opposite way i said sulpuric acid is  a strong oxidising agen (poor reducing agent) and bromine ions and iodide ions they get oxidised which means that they are poor oxidising agents and strong reducing agents


it doesn't matter in what way you put because they both stands for the same answer but the problem is you shouldn't mix up when writing which one is the oxidising and which one is the reducing agent
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Offline Saladin

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #17 on: May 10, 2010, 09:28:24 am »
Quote from: damlaj on May 10, 2010, 09:26:19 am
lol mysterious i said the same thing but in the opposite way i said sulpuric acid is  a strong oxidising agen (poor reducing agent) and bromine ions and iodide ions they get oxidised which means that they are poor oxidising agents and strong reducing agents


it doesn't matter in what way you put because they both stands for the same answer but the problem is you shouldn't mix up when writing which one is the oxidising and which one is the reducing agent

My apologies, i intended it for the person above u. lol
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Offline wrongaccount

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #18 on: May 10, 2010, 11:18:34 am »
thanks alot both of you :D :D i appreciate it :)
and damlaj im a SHE :D
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Offline Saladin

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #19 on: May 10, 2010, 11:20:37 am »
Quote from: helai on May 10, 2010, 11:18:34 am
thanks alot both of you :D :D i appreciate it :)
and damlaj im a SHE :D

LOL
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Offline Uchia

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #20 on: May 10, 2010, 03:29:45 pm »
lol ok my apologies
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Offline Meticulous

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #21 on: May 10, 2010, 04:58:35 pm »
I need help with this question:

" 25 cm3 of potassium iodate (V) solution was added to excess potassium iodide solution. The iodine liberated required 30 cm3 of 0.5 mol dm-3 sodium thiosulphate. Calculate the concentration of the potassium iodate (V) solution."

Needed ASAP.

Thanks in advance.
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Offline Uchia

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #22 on: May 10, 2010, 05:04:38 pm »
at least give us the equation is that cie or edexcel
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Offline Meticulous

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #23 on: May 10, 2010, 05:06:31 pm »
The topic says it's Edexcel, and so it is. It' not a past paper. And there's no equation. Just the way it is. Just a normal thiosulfate titration.
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Offline Meticulous

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #24 on: May 10, 2010, 06:30:24 pm »
Got it now.
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Offline Uchia

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #25 on: May 10, 2010, 06:44:06 pm »
sorry am not sure about the answer hope someone helps soon
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Offline Meticulous

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #26 on: May 10, 2010, 06:45:34 pm »
LOL I said I got it now. Thanks.
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Offline Uchia

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #27 on: May 10, 2010, 08:06:57 pm »
tell me then how did you get it
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Offline Meticulous

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #28 on: May 10, 2010, 08:13:16 pm »
just find the moles of potassium iodate (V) and divide it by its volume. Final answer is 0.1 mol dm-3
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Offline Uchia

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #29 on: May 10, 2010, 09:15:26 pm »
thats what i did 100 percent but I thought that it was wrong cz it was kinda stupid didn't require thinking
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