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Chemistry: Post your doubts here!

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I'm having difficulty in Oct/Nov 2010 Varient 22. Question 3 (e) (ii). The marking scheme isn't very detailed, how did they get:
2059 kJ?
 
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"The idea of tuning the NMR frequency to identify different tissues was not well known" .............how we do this thing mentioned in the statement.....can anyone give the rough idea?
 
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please i'll love notes on electrochemistry and rate of reaction..i'm really failing those topics..thanks
 
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hey what do we need to know about disproportion reactions :confused: ???!!
coz da chemteachers i have are unorganized (they teach one part of a topic one day and the next part after a week =.=)
thanks for any help ^^
 
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AoA! :)
So here's my masla!
It happened today, while we were doing our chemistry practical, that when first we titrated ,we got the volume used of the acid abt 34.5 cm^3. Next time we added about three droppers of indicator into the flask and volume used was 34.2 or .3 something! We couldn't see the colour change properly - the orange of methyl orange and expected pink shade seemed to be so mixed up that neither was recognisible! Third tym we added just four drops of indicator and the volume used reached upto 35! Then we removed the flask and added more indicator to it, shook it and there was the colour change! :p
The answer to the volume used of the acid in the practical's ms was 31 something! There was nothing wrong with the solutions as far as the concentration is concerned so is it possible that the concentration of indicators play a role in titration? If so, then how? Because to what i know, an extra drop of acid from the burette would bring about the same colour change for both 4 drops and 12 drops of indicator! How much indicator do we add in the flask then? Few drops could be anything, as far as instructions on the paper are concerned!
JZK for replying! :)
P.S. The paper is 9701/31/M/J/07
 
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