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As you only have U6B to go, I’m promoting this old post (May 5th) to the top of the blog as it is highly relevant. There is some discussion elsewhere, e.g. ‘the student room’ about on the ‘answer 2 Q’s from 3′ part of Section B.

My advice FOR PART B is: Do as much of 2Q’s as you can possibly do. Then and only then try and do a third Q. And yes, tick ALL three boxes at the end.

Predictions for U6B – WARNING. These are just a guess. It is only the second time I have given predictions. I’m doing so this time because in Jan 09, stu’s said in general it was helpful. THESE PREDICTIONS MAY BE COMPLETELY WRONG. Ignore these predictions if you wish, I make no claim as to their likelyhood other than my own perceptions of that hasn’t appeared in U4 and U5 so far, and what hasn’t had much attention from U1 to U5:

 U6B (June 2009, old syllabus/specification –  June 2002 to June 2009) PREDICTIONS:

1) Gaseous Industrial process (SO2 -> H2SO4, ammonia or HNO3 prodn) involving mostly kinetic factors and catalysis

2) Perhaps a Kp mole fraction type Q possibly in combination with Q1

3) A question based around and acid base titration curve diagram (probably having to sketch one) and indicators and dH(neut)  for strong acids / weak acids.

4) A Born-Haber cycle to calc LE or dH(formation) second part discussing with dH(LE) dH(solution) dH(hyd) variables and a small Hess cycle about this three energy terms.

5) An organic mechanism Q possibly involving carbonyls and KCN / HCN, intermediates and energy profiel curves. Fractional distuallation curve.  OR Mechanism involving markovnikov addition of an electrophile to a C=C and discussion of which is the major product, carbocat intermediates and profile diagrams including Fractional distillation curve. i.e. overall, some kind of aliphatic (’straight chain’) mechanism and discussion of that mechanism. NOTE: I’ve not seen any SN1 / SN2 stuff yet, Such a thing could well be part of this 5th point.

And other than a little bit about teflon (PTFE),  I’ve not seem much organic application (e.g. nylon) and redoxII application (lead acid battery), but I’d say such application stuff may be worth just a few marks tagged on to the end of a question.

I know there are only 4 Q’s on the paper.

That’s it. Now below is the original post:

Some students who come here were not in my group. As such, they may not have heard this info.

It related the the number of Q’s you can do in section B of unit 6B. Without further ado:

Damian Riddle{Damian is representing Edexcel} 
 20/04/2009 01.44 PM
Dear Sir,

Students have a limited time to complete the paper and are strongly recommended to answer only two questions in Section B. If they attempt all three, they are likely to spend too little time on each one and will produce three average answers, rather than two good ones. However, we would mark all three and credit the best two.

Students should use pencil only for graphs and diagrams. Mechanisms can be done in pen.

Damian Riddle

 

If you do decide to answer more than 2 Q’s in section B, you will HAVE to make sure you check the box saying you want all the questions marked. From what I’ve seen of many of you, you will be able to handle doing 3 Q’s.

If you do want to do 3Q’’s, try and do two FULL Q’s first before you attempt the remaining Q. Otherwise, you may end up getting the same marks for half-doing one Q as you will for half-doing a third Q but you will have wasted almost double the amount of time.

And remember, make sure you read ALL section B questions first before you decide which ones to try first.

This brings me to a general point. In the trials, the number of marks lost because students did not read (or understand) what the Q was asking you for, was too high. Carefully read the Q and figure out what key points it is looking for. If you’ve done loads of past years papers, this should be quite routine. Yes there will be twists, but the twist will still be based on the same knowledge you are required to have.