ocr a f325 revision thread

is this module particularly harder then the first?

nice! Well done


Why does increasing temperature increase entropy (2)

Entropy is a measure of disorder, And as temperature increases particles have more kinetic energy so have more degrees of arranging their particles which is a component needed when working out entropy, as the number of ways to arrange particles in space increases, as does entropy

that was really wishy washy haha. Not entirely sure if i hit the marking points, let me know.

Why do some reactions which are feasible at room temperature, not appear to happen on its own.

A small tip for people who are aiming for the A*:

If you want the A*, you have to do additional reading on all the topics in f325 on chemguide as well as learning the textbook. The textbook is often too brief, whereas chemguide literally covers EVERYTHING to do with all the topics of f325.
I sat f325 in Jan and got an A but I'm resitting to get an A*-I was only five marks off it in Jan. Having looked back at my paper, I would have easily gained those 5 marks had I done the additional reading on chemguide.
Some may argue that doing stretch and challenge questions is enough. However, I would argue that this isn't enough, as OCR change them every series. I did all the ones I could find before Jan, but OCR set totally different ones in the real exam, which I really struggled with.
Doing legacy papers also helps

ChemGuide goes way too much detail. Not sure if serious.

Did you do every single Exam question in the Book under Exam conditions and understand your mistakes?

Because the official textbook for OCR is actually really good. It has like 14 Exam Questions from 2002-2006 all Legacy Questions for Each topic. You can even type in the questions verbatim, in google and PDF's come up of the year.

I want an A* too:
1. All module question
2. Don't look at a Past Paper till I'm 100% ready I understood any mistakes on Module/Legacy Exam Questions
3. Past Papers timed as if its real.

I don't know but my thinking is that going on Chemguide would just distract you especially seeing as its got stuff that isn't on our syllabus?

Don't think that is a good idea. Edit: And doing more dumb work is why I have gotten A's all the time and not A*'s I think, even my Chemistry Tutor who got a 1st in Chemistry from a Top 10 Uni, was like don't waste time reading extra stuff. Just test yourself, using the index of the page to see if you can remember everything just by looking at a Topic Title.

What book do you use out of interest.. as in who is the publicist, because we were given a 'Hodder education' one and i reckon its pretty bad

You do make some very perceptive points here.
I used to think that would be enough before January. All of the past papers OCR had set June 2010-June 2012, don't really require a lot of additional reading to get an A* (maybe with the possible exception of Jan 11). The A* is more based on exam technique. However, in January 2013 there were a lot of questions in unfamiliar contexts that you could easily have answered had you done the additional reading-you will realise this when you see the paper.
From the trend A Level exams seem to be taking this year, it would not in the least bit surprising if OCR decided to set an equally difficult paper this summer, which is why I think chemguide is a very useful resource-both my teachers have said you need to do additional reading from it to get the A*. Now obviously, I'm not saying look at every paper on chemguide, but you can narrow it down quite easily to what's on the OCR syllabus.

This is what we are using.


http://www.amazon.co.uk/OCR-Chemistry-Student-Book-CD-ROM/dp/0435691988/ref=pd_sim_b_3%3Ftag=68656c7064757-20

Same! It's a brilliant book

This is what we are using.


http://www.amazon.co.uk/OCR-Chemistry-Student-Book-CD-ROM/dp/0435691988/ref=pd_sim_b_3%3Ftag=68656c7064757-20

you see, we get this crud
http://www.amazon.co.uk/OCR-Chemistry-A2-Dynamic-Learning/dp/0340974931/ref=sr_1_9?s=books&ie=UTF8&qid=1365806856&sr=1-9&keywords=ocr+a2+chemistry+hodders

I'm Sorry to hear that pal. Don't be discouraged - we're all gonna make it brah.

My suggestions -

1. Get the Book
2. Put it in a a chamber of a Halogen gas i.e Cl2
3. Put in some Sodium.

Watch it burn, then buy our book and calculate the Standard Lattice Enthalpy of the exothermic reaction that just occurred.

Note: After I just wrote this joke I was proud of how much of a loser I have become, and also how it means I am on track.

is your book really that good? Might invest

is your book really that good? might invest

That is a sensible answer and is worthy of full marks!

because firstly, for a reaction to be feasible and to take place deta G<0 and there are 3 factors that contribute to this effect and they are temperature,enthalpy and entropy. This could be because that tdetas>0. this could be because the enthalpy is positive and therefore, the chemical system is stable because energy is absrobed into the chemical system from the surrounding

Sorry haha i overlooked it

i know where you're coming from with your answer but i was kind of aiming toward the idea of kinetic inertness and that even though a reaction would appear to be feasible/spontaneous nothing happens. There is no visible change because the rate of reaction is too slow to be noticeable, which could be caused by a high activation energy.

I think my ability to structure a question could be at fault, sorry!

I have the jan 2013 QP and MS, so if anyone wants it, just pm me your email and i'll send it to you

I knew that answer, but well said though.

Suggest role of pt electrode

a Pt electrode can be used as part of the external circuit in a halfcell, because it is capable of carrying electrons, so is a conductor and it is also very unreactive so is unlikely to get involved in the reaction