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Christophicus
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I would like someone, (rep is available) to give me advice on assessment objectives A and D for practical chemistry. I would be really really grateful.

A Planning and Design
The ability to:
1 identify and define a problem
2 retrieve and evaluate information from multiple sources, including computer databases where appropriate
3 plan an appropriate general approach
4 give details of the method, including quantities of substances, purity of reagents and products, and suitable experimental points if appropriate
5 propose suitable reagents and apparatus
6 be able to adapt original plans in the light of preliminary findings where appropriate
7 demonstrate a regard for safe working in the choice of method and apparatus
8 propose scale of working and control of variables where appropriate.

D Interpretation and evaluation of experimental results
The ability to:
1 recognise the correct functions and/or equations to use in a calculation
2 be able to complete a calculation and to do so in an efficient and economical manner
3 present results graphically and obtain information from a graph
4 collate information (found from experiment or in conjunction with provided information, including the processing of data using information technology) to arrive at a final conclusion such as the identity of a substance or its molecular structure
5 interpret information gathered from experimental activities including:
a manipulation of data
b recognition of patterns and trends in a set of data or information
6 evaluate critically the experimental work, including identification of, and accounting for,anomalous results and experimental error, and suggest related improvements to methods
7 assess the reliability of data and conclusions drawn from it
8 evaluate techniques used in a particular experimental activity, recognising their limitations
9 make a quantitative estimate of experimental error and evaluate the limitations of the method used.

I have found out that I am doing the internal assessment for unit 3 part A, part B is the written exam in June I think.
If anyone has any good advice for the internal assessment for unit 3 edexcel chemistry then please post your pointers here.

Thankyou in advance.
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footballhead
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I just did my exam the A+D section you have written about above, a few days ago. Its not that hard at all, you have to identify 3 powders, for the first section, just do the tests they are very easy to follow, and write down EVERYTHING you see, but they are mostly quite obvious stuff for example hlowing splint is relighted, hydrogen makes it pop etc. But dont bother writing what it could be : so dont say its oxygen if it relights a glowing splint, just say it does. Also if you suspect its something, do a few litmus tests, and write about what happens, oh yeah be very careful when doing litmus tests, you know how its bromine or chlorine ( i think) that the speed of bleaching shows diff. substances- so watch carefully. Then after all that, you do the D section inferences - open book- just prepare all your notes on cation/ion tests and group 7 /1 etc elements. Look at the test so if its a flame test- you know its going to do with the cation-and just check the colour and write it down.

When you've written your inferences down and figured out what the substances are, go back and change your A section observations- to cater with your inferences - for the stuff u might have missed out- if that makes any sense ?? for example if you knew that its potassium something but wrote down the wrong colour for the flame test.

Also the ones with 3 marks- write down the redox equation- write loads if ure unsure-they wont mark u down for writing extra stuff..

I hope this helps..im not very good at chemistry, and so i might be talking about something completely different.
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Christophicus
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What sort of stuff is involved in the planning section?
Is it a titration?
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footballhead
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No well one of the sep. experiements was titration but the one i did for the two part one was:

3 powders and u did loads of easy stuff like flame tests, trst for ammonia, adding HCl burning it etc etc its not that hard at all- chill
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Christophicus
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One of the points in the spec says;
carry out the techniques used in volumetric analysis and enthalpy change measurements
assessment exercises will be limited to acid-base titrations as a matter of recall. In exercises of any other type full details of technique will be provided.

So for titrations they might say, titrate solution A against solution B. Is that it? They will give quantities right?
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idiopathic
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You might have to make the solutions yourself (eg if given anhydrous compounds). Other than that, a titration is simple to do, but it's probably the calculations that are tricky, and finding enough to write about in any evaluation.

For a titration remember your decimal points, and make sure you have 2 titres which are within the given accuracy.
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Christophicus
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(Original post by endeavour)
You might have to make the solutions yourself (eg if given anhydrous compounds). Other than that, a titration is simple to do, but it's probably the calculations that are tricky, and finding enough to write about in any evaluation.

For a titration remember your decimal points, and make sure you have 2 titres which are within the given accuracy.
Could you explain this part please?
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Christophicus
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Any more advice?
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footballhead
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Where'z my rep woman
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Christophicus
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I've given out rep within the last 24 hours, sorry.
P.S I'm a bloke.
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Christophicus
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Does anyone have any pointers and things to watch out for in titrations and identifying salts practicals?
I would appreciate this.
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shark
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u know chemistry as well as any one should know, so keep up da good work. u make it seem very easy anyway best of luck to every one who deals wid this stuff.
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kubra
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[B]looks like all u are really clever sorry to interupt but i need help with a question i,m going round asking everyone plzzzzzzzzzzz help me.
need to give it in on friday its part of an assignment
this is exactly how the question is written:-

In the petrochemical industry, alkenes r hydrated to give several solvents. with this information, deduce how ethanol and propanol could be produced.
comment on the molecular shape of the alkene used in the production of ethanol in terms of its commercial uses.

i got the info on how ethene is hydrated but having difficulty on how propene is hydrated plzzzzzzzzzzz some on help me.
i want as-level standard thanks.[/B]
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kubra
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if someone even has a good website on organic chemistry plz do tell thanks on my yahoo mail
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ccccecil
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Unit 3A is open book right? So bring all your Unit 3B past papers, you might find it helpful when doing the 3A practical exam.
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