[Sorro10]

Yea written one is on 23rd

[cuckoo99]

em that unit 1 jan 2012 paper is missing the first question for some reason first question asks about covalent bonding if i remember rightly.

[Jcon1]

(Original post by cuckoo99)
em that unit 1 jan 2012 paper is missing the first question for some reason first question asks about covalent bonding if i remember rightly.

Dative Covalent (co-ordinative, Coordinate Covalent Bonds) i believe .
Also, i have been revising Unit 2 for quite a while if anyone can give me any tips or advice it would be much appreciated as of current i am just trying to remember by repetition.
Extra Info: I didn't do well on Unit 1 due to panicking and failed to be not lazy and do revision over Christmas and played COD instead..that has stopped now

[W4L1Y]

Yea sorry i got confused with my maths C2 exam lol

[kingam]

(Original post by W4L1Y)
Yea sorry i got confused with my maths C2 exam lol

what did you get in chem 1 dont mind me asking lol , going to do it june again

[Doctor.]

(Original post by Jcon1)
Dative Covalent (co-ordinative, Coordinate Covalent Bonds) i believe .
Also, i have been revising Unit 2 for quite a while if anyone can give me any tips or advice it would be much appreciated as of current i am just trying to remember by repetition.
Extra Info: I didn't do well on Unit 1 due to panicking and failed to be not lazy and do revision over Christmas and played COD instead..that has stopped now

For unit 2, best advise I can give Is just make sure you know the definitions from the small blue Collins book. My teacher went to one of the examiners questions days and he had with him the small blue Collins book and literally referred to most of the book throghout the day!

the NT book...he didn't even use it once! It's too much 'how science works' not enough raw content!

It's a larger paper, considerably. Just take it question by question and don't get too complacent! Revision for the exam is really needed

[W4L1Y]

i got a C was one ums of a b i could have done really good but realy really silly mistakes like the deviation question i put oxygen when it was Boron lol

[cuckoo99]

(Original post by Jcon1)
Dative Covalent (co-ordinative, Coordinate Covalent Bonds) i believe .
Also, i have been revising Unit 2 for quite a while if anyone can give me any tips or advice it would be much appreciated as of current i am just trying to remember by repetition.
Extra Info: I didn't do well on Unit 1 due to panicking and failed to be not lazy and do revision over Christmas and played COD instead..that has stopped now

nah it was asking for the definition of a covalent bond e.g sharing of a pair of electrons between 2 atoms. i did badly aswell though it was due to some personal problems, i got a D

[Learner_108]

Has anyone got the CHEM2 JAN 2012 QUESTION PAPER? ive been looking all over for it. if you have this paper can you please upload it?

[Luppy021]

(Original post by Learner_108)
Has anyone got the CHEM2 JAN 2012 QUESTION PAPER? ive been looking all over for it. if you have this paper can you please upload it?

I second this, wouldn't mind starting to print off my past papers now

[Mocking_bird]

The amount of equations in Extraction of Metals is making me go crazy

[rommy123]

(Original post by Mocking_bird)
The amount of equations in Extraction of Metals is making me go crazy

Lol same here

[Tullia]

(Original post by Mocking_bird)
The amount of equations in Extraction of Metals is making me go crazy

If you can't handle the heat then get out of the blast furnace.

[cuckoo99]

(Original post by Mocking_bird)
The amount of equations in Extraction of Metals is making me go crazy

hehehe off the top of my head there is :
2Fe2O3 + 3C ----> 4Fe + 3CO2
WO3 + 3H2 ----> W + 3H2O
Fe2O3 + 2Al -----> Al2O3 + Fe
TiO2 + 2Cl2+ 2C ----> TiCl4 + 2CO
TiCl4+4Na -----> Ti + 4NaCl
2V2O5 + 5Si ------> 5SiO2 + 4V

and electrolysis half equations:
Al3+ + 3e- ------> Al
2O2- ----> O2 + 4e-

[MedicalMayhem]

Hi guys, I've got a question on adding sulphuric acid to the halide solutions, as I wrote something in class but it conflicts with the answers found on a-level chemistry.

So it's when you add bromide ions to sulphuric acid.

Half equations:
2Br- --> Br2 + 2e-
2e- + 2H+ + H2SO4 --> SO2 + 2H2O

Are these right?

As I thought you just combine them, and you get 2Br- + 2H+ + H2SO4 --> Br2 + SO2 + 2H2O. But the a-level chemistry website says: 2H2SO4 + 2Br- --> SO2+ Br2 + 2H2O + SO4^2-.

Can someone explain which one is correct please?

[Mocking_bird]

(Original post by cuckoo99)
hehehe off the top of my head there is :
2Fe2O3 + 3C ----> 4Fe + 3CO2
WO3 + 3H2 ----> W + 3H2O
Fe2O3 + 2Al -----> Al2O3 + Fe
TiO2 + 2Cl2+ 2C ----> TiCl4 + 2CO
TiCl4+4Na -----> Ti + 4NaCl

and electrolysis half equations:
Al3+ + 3e- ------> Al
2O2- ----> O2 + 4e-

I have more than that on just the first 2 pages of my booklets
Will type them up later maybe so somebody can hopefully tell me i'm learning way more than i need to,

[ElMoro]

(Original post by Mocking_bird)
The amount of equations in Extraction of Metals is making me go crazy

I'm sure there's not that many

[Tullia]

(Original post by MedicalMayhem)

2Br- --> Br2 + 2e-
2e- + 2H+ + H2SO4 --> SO2 + 2H2O


2Br- + 2H+ + H2SO4 --> Br2 + SO2 + 2H2O.

Nothing wrong with those.

[MedicalMayhem]

(Original post by Tullia)
Nothing wrong with those.

Ah okay, so in an exam that'd be okay? What's the other thing talking about then, with the sulphate ions? Is that equation correct as well?

[Mocking_bird]

So this is too much then?

Extraction of Iron
1) Coke reacts with hot air - very exothermic, responsible for high temps in furnace


2) Carbon dioxide at high temps reacts with unreacted coke


3) Carbon monoxide acts as a reducing agent and reduces most of Iron(III) oxide.


4) Coke also acts as a reducing agent in the hotter area of the furnace at the bottom.


5) Limestone is used to remove impurities. Limestone first decomposes.


6) Calcium oxide produced is a basic oxide and reacts with acidic oxides.


Extraction of Copper:
Original method:
1) Reduce ore to copper oxide by heating


2) Oxide heated with coke


3) Overall equation:


Recent way:
.

Extraction of Maganese:


Extraction of Tungsten:


So thats not including extraction of aluminium (4 equations), titanium(2 equations), carbide formation (1) , and 3 pollution problem equations. [Didnt want to type them out as if i've not learnt that far yet].
If ive just learnt all them for no reason my teacher is evil for giving us this booklet to learn on our own