F334 (14/01/2013 1:30PM) - Salters Chemistry (Chemistry of Materials) Revision Thread

Have people noticed that on page 69 of the CGP revision guide, the complex ion [Fe(H2O)6]3+ is said to be violet but on page 70 it is said to be orange/brown. ??? I thought the Fe2+ ion and complex ions are always orange/brown. Could someone confirm this for me ?

Help is much appreciated!

Nobody seems to have the June 2012 paper sadly, I think that schools are going to use it for the mock exams

It does say on page 69, by the little arrow, that it usually looks yellow. I would imagine that this color is like orange and brown. However, looking at past papers, I have always put down yellow/yellow-brown to be safe.

According to this powerpoint my teacher gave me, it is like ruby, or brown. Rather confusing, I'll ask my teacher for confirmation. I would stick to yellow/yellow-brown/orange.

Ok that is so confusing because it says violet/yellow on page 69, then orange/brown on the next page wth!

Okay, so in school we've only just started whats in a medicine....but i've done it all on my own by self-teaching
I am really worried i wont get a good grade in this exam....i dont understand the electrode potentials ( I get the maths behind it, but not the chemistry )
i dont get the effect of concentration also...i get the maths behind it though, not the theory. But other than this, I am fine with the rest of the syllabus, ( oooh, except from the DNA structure ). We have a month and 2 weeks left till our chemistry exam... is this enough time to go over all subjects, plus learn the things i dont get, and also do past paper questions? It a lot to do, and i am not sure if its fine or not Is it too late?

It's not too late if you start going over your notes now. Make sure you understand every topic, and do some questions in the chemical ideas textbook to test your knowledge. I would say spend a day doing two topics, so that would take around 10 days.

That should leave you with ample time to start the past papers, and you should finish them by the last week of the Christmas hols. Then you can spend the remaining time fine-tuning your knowledge, and doing more exercises.

I've uploaded this useful PDF I found on electrode potentials, as that is quite a tricky topic. The CGP revision guide really helps, and for the effect on concentration on rate, the chemical ideas book is awesome. Make notes, cover them up and test what you remember, go back and see where your knowledge gaps are. Then do loads of questions to fully understand the topic!

Standard Electrode Potentials & Cells.pdf

Good luck

yes, i have started revising over everything... i spent about a whole day on electrode potentials...woke up in the morning at 4 am, to do some revision i understand it , but i dont know what depth do they want us to know it to?

this is what i know :-
i can draw diagrams of electrochemical cells
i can do calculations involving half-cells
if you have suppose 2 ions produced, then you use a platinum electrode.
The half cell with more positive standard electrode potential is at the positive terminal. This is means, its a stronger oxidising agent - so it gets reduced. Hence, the reducing agent at the negative terminal will get oxidised and provide electrons for the positive terminal so it gets reduced.
the more stronger oxidising agent reverses the less positive one .

Thats all i know really...is there anything more?

also, whats a better way of remembering experimental techniques..there are just sooo many,

Thank you

In past exam papers, they have asked you to draw an electrochemical cell, so I would make sure I learn how to draw one. Standard textbooks cover this well.

You understand the foundations perfectly, in an exam they will ask you to apply this. They give you a table of electrode potentials, and they will ask if a certain reaction is feasible. They might also ask to draw the overall equation happening in the electrochemical cell.

Here is an example question:




Can you do this question?

And on remembering the practical procedures, I'm afraid the only way is to learn them; by memorisation. What would help, is actually doing the practicals; but in my school we hardly had the time or equipment to do so. So yeah, just persevere in memorising them Focus on TLC, colorimetry and recrystallisation.

Good luck