[sphixter]

The edexcel A2 exams are in a few days guys. Lets gather up everything we know generaly comes in the past papers and put it together so that we have a list of likely questions.

I'll go first.

Unit 4 - Born-Haber cycle- This always seems to come up so learning it might
be best
Organic - this always comes for at least 15 - 20 marks so knowing
this well should give a good block of easy marks.

Everyone else, please contribute. Together we can beat this thing!

[Excalibur]

They always include all the topics in one way or the other!

Unit 4

- Energetics: Born Haber cycle or enthalpy of solution Hess' cycle. Explanation about why LE changes down group 2; why the difference in experimental/theoretical values differ down group 2; solubility explanation.

- Periodic table: random equations? They quite like you to write equations showing the amphoteric nature of Al, or the trend across a period/down a group in terms of acid/base character. Also the +2 more stable down group 4; why CCl4 does not react but SiCl4 does.

- Chem equilibria: calculations. Effect of temperature/pressure/conc on Kp and Kc and explanations thereof.

- Acid/base equilibria: calculating pH of buffer or pH of weak acid usually comes up. Usually definitions (pH, weak, acid/base, buffer, Kw). Drawing titration curves, or picking an indicator.

- Organic: hmm, can throw anything at you. Just know it They quite like iodoform, sometimes ask you to draw the structure of 2,4DNPH, distinction between aldehyde and ketone, reagents & conditions for formation of hydroxynitrile.

Unit 5

- Redox equilibria: know your thiosulphate/iodine titration & equation and the KMnO4- titration. Basically, for every electrode potential question always work out the Ecell and comment (i.e. +ve so feasible etc) and they're bound to give you a mark

- Transition Metals: equations for deprotonation (both with water and with OH-) and ligand exchange. Explanation of colour comes up a lot, as well as explain why it is an octahedral structure. Linking E standard values with vanadium chemistry. Sometimes asks questions on the industrial chem from Unit 2.

- Organic: can usually bank on a Friedel-Crafts or nitration mechanism, including the formation of the electrophile. Benzene diazonium chloride and its coupling reaction comes up a lot. Structure of benzene and why it is more stable/has different hydrogenation etc values than expected.

- Kinetics: working out rate equation & rate constant; a few definitions. Experimental techniques (titration seems most common). Effect of temperature/catalyst on k. They also like to throw in iodoform when talking about the reaction with propanone and iodine.

- Organic analysis: sometimes a question on IR or nmr, more rarely on mass spec. Have never seen a question on visible/UV spectroscopy, though.... Recrystallisation (once saw a paper asking you to justify each step), and boiling point composition diagrams (incl how to explain the tie lines). Uses of polymers and formation of polymers by condensation or by addition.

[shungun]

unit 4

also remember the indicators for the different neutralizations...
also reaction with DNP

one last thing...

if they ask you for formula or an equation with aluminium chloride...do you put AlCl3 or Al2Cl6 because it is dimeric??? i found out that both are not accepted in the markscheme... which one do we always use ???thanks

[Prudy]

My perspective having tewice taken A2: Remember the topics that came up in U4 and U5. It is highly likely that the ones that don't come up will be on U6b

[~Adel~]

For unit 5, one HAS to know all the mechanisms, you'll easily get a few questions on those which could sum up to 7 or even 10 marks!!