[eebootwo]

(Original post by numpty1225)
what is Ostwald's process anyway?

Producing Nitric Acid.

[member963009]

(Original post by ak2109)
Not a clue? Everyone does Paper 1C which is the double award paper? Then those doing it as a separate IGCSE do a paper 2C, correct? Therefore I am assuming electrolysis calculations will be in paper 2C.

However I must query, how different are the June 2011/January 2012 papers from the one we shall do tomorrow? Especially the January paper I wonder.

Electrolysis equation appear on Paper 2 as they are for people taking all three iGCSEs not just the double award. So they do not appear on paper 1.

[ak2109]

(Original post by Big-Daddy)
Ostwald, you mean? No. It is in the textbook but not on the spec.

It is not in my textbook? :O

[numpty1225]

(Original post by sahajkaur)
Your statement is misleading. The pressure won't affect the ROR (only when there are gases involved in which case you are changing the concentration aswell). It only affects the yield. Here N2 + 3H2 --><-- 2NH3 the products have less moles (2) whereas reactants have 4. So the rule still applies here. The equilibrium shifts to the right to give a higher yield. When concerned about yield the right is always the product seeked for. Why is it going to shift to the left? That would go against Le Chatelier's principle. I think you've confused yourself here. What Quark_Assassin said is absolutely right.

Is the forward reaction normally exothermic in a given reversible reaction?

[ak2109]

(Original post by sahajkaur)
Electrolysis equation appear on Paper 2 as they are for people taking all three iGCSEs not just the double award. So they do not appear on paper 1.

In regards to format/difficulty of different exam seasons' papers?

[Pretending2study]

(Original post by ak2109)
There are the papers + mark schemes

Thankyouu ;D

[member963009]

(Original post by Pretending2study)
Can anybody gimmi a link for the Jan 2012 papers?

Here. I uploaded them on my skydrive for you.

Paper 1:https://skydrive.live.com/?cid=f2560...AFEB3C10%21299
https://skydrive.live.com/redir?resi...94AFEB3C10!302
Paper 1 MS: https://skydrive.live.com/#cid=F2560...0&sc=documents

Paper 2: https://skydrive.live.com/?cid=f2560...AFEB3C10%21302
Paper 2 MS: https://skydrive.live.com/?cid=f2560...AFEB3C10%21301

[Quark_Assassin]

The Jan paper was VERY easy. So June should also be quite easy. Got em for my mocks the Jan papers.

[member963009]

(Original post by numpty1225)
Is the forward reaction normally exothermic in a given reversible reaction?

They can be. But there's no set rule.

[member963009]

(Original post by ak2109)
In regards to format/difficulty of different exam seasons' papers?

Argh you uploaded the papers before me :P haha. Personally I think the papers so far have been straightforward and easy but people may disagree. We shall see tomorrow.

[Pretending2study]

(Original post by sahajkaur)
Here. I uploaded them on my skydrive for you.

Paper 1:https://skydrive.live.com/?cid=f2560...AFEB3C10%21299
https://skydrive.live.com/redir?resi...94AFEB3C10!302
Paper 1 MS: https://skydrive.live.com/#cid=F2560...0&sc=documents

Paper 2: https://skydrive.live.com/?cid=f2560...AFEB3C10%21302
Paper 2 MS: https://skydrive.live.com/?cid=f2560...AFEB3C10%21301

Thankss!

[ak2109]

(Original post by Quark_Assassin)
The Jan paper was VERY easy. So June should also be quite easy. Got em for my mocks the Jan papers.

YES in fact I was doing it yesterday! I made a few silly errors but it still went Ok I guess :P I was relatively pleased with my mark.

[numpty1225]

what must you say for the methylbenzene question?

[ak2109]

(Original post by sahajkaur)
Argh you uploaded the papers before me :P haha. Personally I think the papers so far have been straightforward and easy but people may disagree. We shall see tomorrow.

Again, I personally found them ok. In the old spec, I don't know if it applies now. November 2010 2H Paper, question on observation of reaction between Hydrogen Iodide and Sodium Carbonate. Are we supposed to know this? I have not learnt it.

[member963009]

(Original post by numpty1225)
what must you say for the methylbenzene question?

Just remember this. When HCl dissolves in Methylbenzene, it does not exhibit its acidic properties. It is because methylbenzene is an organic solvent in which HCl doesn't ionize. Any substance displays acidic properties because it ionizes to give an H+ ion. So if it doesn't ionize, it will display none of those properties such as turning blue litmus red.

[member963009]

(Original post by ak2109)
Again, I personally found them ok. In the old spec, I don't know if it applies now. November 2010 2H Paper, question on observation of reaction between Hydrogen Iodide and Sodium Carbonate. Are we supposed to know this? I have not learnt it.

No we aren't. The old spec contain some things that are not relevant to the new spec. After all it is the new spec .

[ak2109]

(Original post by numpty1225)
what must you say for the methylbenzene question?

No disassociation of H+ ions so therefore there is no acidic solution formed. This prevents it from changing colour.

[ak2109]

(Original post by sahajkaur)
No we aren't. The old spec contain some things that are not relevant to the new spec. After all it is the new spec .

Ah, just needed to check. I was quite worried about it :P. Also, are Esters on the new spec?

[Carmeee]

http://www.scribd.com/doc/55987625/I...Chemistry-SAMs
UH...HOW TO DRAW 4(II)????

[nitrome]

(Original post by sahajkaur)
Enthalpy change = mass of solution x change in temp x specific heat capacity of water

mass of solution: 30 g
temp change: 27-22.1 = 24.9

so enthalpy change: 30 * 24.9 * 4.2 (specific heat capacity of water)
=3137




Rate increases with temperature as the molecules collide more often and more energy so there is an increased chance of collisions happening with the required activation energy meaning that the frequency of successful collisions increases. It increases with a catalyst as the catalyst provides a alternate pathway with a lower activation energy meaning more collisions that take place have the required activation energy meaning that the frequency of successful collisions increases. Pressure (when reacts gases) forces more of them together in the given volume so it kind of acts like concentration. That means in a given volume there are more reactants meaning there will be more successful collisions per second.

Yield (presumably you're talking about this in the context of reversible reactions in equilibrium) increases with more pressure if the products have less moles than the reactants e.g. N2 + 3H2 --><-- 2NH3 where reactants have 4 moles and the products only have 2. The previous example is exothermic so I like to write exothermic equations like this: (and vice versa) N2 + 3H2 --><-- 2NH3 + heat. Here is the temperature is increased the equilibrium will shift to the left, decreased yield. Catalyst has no effect no yield, it just speeds up the closed container obtaining equilibrium. Hope this helps!

thank you!