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ppa's question


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#1 neep

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Posted 02 June 2009 - 03:06 PM

how much about each ppa are we actually ment to know. do you need to know each step in all the reactions and all the chemicals used and all the equations?

#2 ginneswatson

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Posted 02 June 2009 - 04:35 PM

QUOTE (neep @ Jun 2 2009, 04:06 PM) <{POST_SNAPBACK}>
how much about each ppa are we actually ment to know. do you need to know each step in all the reactions and all the chemicals used and all the equations?

For the most part no.

If you look through a Past Paper you might not even spot all the PPA questions. More often you are expected to have absorbed some of the more general principles (weighing accurately, making up solutions, end-points, separating techniques etc) rather than specific details.

A quick glance at the 2008 paper and I only spotted two questions based on the practical side of the PPA's. One asked for the indicator used when determining the concentration of Iodine in a partition coefficient question (starch). The second one asked how to purify a 2,4-dinitrophenylhydrazone derivative (recrystallisation).

Not worth worrying too much about.

Might be worth trawling through some of the Forum discussions from previous years to see what people have made of the PPA's in the past.

#3 neep

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Posted 02 June 2009 - 04:42 PM

ok thanks. i panicked when i looked at all the stuff in my book about them and relised i didnt know most of the chemicals





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