AQA CHEM5 A2 Chemistry - 19th June 2013

Posted from TSR Mobile

What is the best way to remember those redox equations? Are you guys just writing them out over and over again to remember them?

[Co(H₂O)₆]²⁺ (aq) + 6 NH₃ (aq) --> [Co(NH₃)₆]²⁺ (aq) + 6 H₂O (l)

[Co(H₂O)₆]²⁺ (aq) is unstable in the presence of oxygen, so Co²⁺ is oxidised to Co³⁺

4 [Co(NH₃)₆]²⁺ (aq) + O₂ (aq) + 4 H⁺ (aq) --> 4 [Co(NH₃)₆]³⁺ (aq) + 2 H₂O (l)

Does that help?

Posted from TSR Mobile

How are you guys revising?

I am just making revisiom notes so that I have plenty of time to do past papers before the actual thing.

the reactions of metal aqua ions with a little NaOH or a little NH3, I know both reactions have the same product a pppt M(H2O)4(OH)2 with 2+ ions, but when you write out the equation can you just write + 2OH- for NaOH and NH3 or do you have to write +NH3 --> NH4+ for adding a little ammonia?

hope you understand my little ramble... thanks

hi,
does anyone have a paragraph on cis-platin
thanks for any help

me

Cisplatin is a Cancer drug, structural formula is (NH3)2PtCl2, it has a square planar structure which is has both Cl's on one side, the NH3's on the other hence the 'cis' name. You do not need to know how it works, but for your own interest the N in guanine displaces the Cl and forms a coordinate bond. (correct me if I'm wrong)

Cisplatin has side effects because it attacks guanine in healthy DNA as well as in cancerous cells.

And that is about it!

In my text book, it says the colour [Fe(H20)6]^3+ can be purple/yellow/brown. Which one do markchemes prefer?

Posted from TSR Mobile

Without breaking any rules,has anyone got any tips for the transition metal isa? Just like the tips on revision areas your teacher gave you before. I don't have a teacher so have no one to tell me what areas to revise

Hello,

I am revising from three textbooks mainly (the main textbook endorsed by AQA, the CGP revision guide and Collins revision guide finally). The CGP revision guide is lovely for CHEM4 and CHEM5 ; the notes are clear, concise and well organised! But, unfortunately, they do not contain everything you need to know to get 'the top grades' . So after you make notes from them, remember to go through your aqa textbook and also the collins revision guide thoroughly. Add 'extra notes'.

I think this is a good time to start on some past papers - not the new ones but the legacy papers (these are the one from 2002- 2008). They give good practice. If you leave past papers to the final minute, it is going to be a bit of a struggle. Chemistry is one of those subjects where practice makes perfect, especially because of the fact that the mark schemes are very very specific. It is good to know (at an early stage) what kind of answer is awarded and what is rejected! If you get something wrong, remember to make a note of it and then revise that section again + copy down the mark scheme answer. But don't just copy down mark scheme answer ...make sure you understand what is going on (ask on here if you don't)!

Finally, this seems to be a topic with loads and loads of equations - so what i did personally (to help me) is make little cards with all of the equations on them. So when you do past papers, you can just flick through the card pack to get to the appropriate equation instead of going through ALL your notes! Makes life much easier.

Oh and finally, remember to revise the synoptic stuff from CHEM1.

Hope all this advice is helpful!

Purple on the whole

Do you know what they prefer for [Cr(H₂O)₆]²⁺? And for[CuCl₄]^2-?

blue, and CuCL4- is yellow-green

I mean Chromium, not Copper - and thanks!