Edexcel chemistry - unit 2 19th january 2012

Helllooooo People
Hoping everyone's revision is going goood

This thread is made for revision & discussion of anything related to unit 2 chemistry
Just thought if everyone would share their useful chemistry knowledge & make the world richer :P

Goood Luck folks

I'm re-sitting this unit as I got a B overall in AS Chemistry last year but was just 6 UMS marks off an A. To make it easier for me to get an A overall in the A2 exams it was best to resit otherwise it will hold me back!

I'm working my way through the Edexcel AS Students' Book and I've finished the first 3 chapters (shapes of molecules, electronegativity and intermolecular forces) so just about to start redox. How's your revision going?

I'm resitting this unit as well... this year the unit 2 paper was waaay tooo difficult !

I know! I didn't do too badly on the MC section but I fell down on the structured section, especially the diagram question for 4 marks, the titrations and the NO2 question. Which questions did you find difficult?

I'll be doing this unit again. The most difficult part is probably group 2 and 7 stuff, a lot to remember.

the hardest thing is memorizing colour of iodine in different things !! chlorine is mostly pale yellow , bromine is brown , iodine is different in every thing !!!!!

I know what you're saying, although I remember iodine easily because it's violet in an organic solvent which is quite a bold colour!

I think the best way to learn the Group 7 colours in water and organic solvent is just to write them out over and over again and perhaps cover up the halogen or its colour and name it from memory.

A couple of points:
1. I read an examiner's report of Edexcel Unit 2 and they said that they prefer you to say pale green or green in terms of the colour of chlorine in water, although 'virtually colourless' may be accepted occasionally.

2. It's best to say bromine is yellow-orange in water because strictly speaking iodine is brown in water, so saying they are both brown wouldn't be correct!

aww jee thanks !! those are some nice tips ...! so iodine in hydrocarbon solvent is red or violet ....?!? i read somewhere red ...?!

Purple/violet.

so does anyone have checklist or just a list of different types of experiment we should know how to draw out?

Based on what apparatus is drawn in most AS textbooks, I should think the following pieces of apparatus are good to know how to draw:

-Reflux apparatus
-Distillation apparatus
-Separating funnels
-Gas syringes

There isn't a lot else they can ask to be honest, but I was reading something written by a chief examiner and they said that diagrams aren't drawn particularly well in exams at the moment! The most common one is probably people drawing sealed apparatus (which in reality would cause a build-up of pressure therefore explosion!)

I think you also have to know about errors with apparatus, e.g. incorrect water flow, sealed apparatus, thermometer bulb too high in distillation apparatus etc. as it came up in one of the 2009 papers (June I think).

Hope that helps.

THANKS! do you have any usefull links for those drawing?

Have a look here for the reflux and distillation apparatus. There's a good diagram of a separating funnel here on Chemguide (towards the bottom of the page).

THANKS YOU!!!

also can you tell me, do we need to know about group2 stuff for unit1?