[master_blaster66]

(Original post by Ilyas)
what's the boundary for an A?

85/120

[Iepnauy]

This exam is brutal =(.

Wish I started revising for it earlier. Did horrifically on the past paper I just did =/

[master_blaster66]

(Original post by Iepnauy)
This exam is brutal =(.

Wish I started revising for it earlier. Did horrifically on the past paper I just did =/

the boundaries are quiet low usually, so dont worry youll be okay

[navarre]

(Original post by master_blaster66)
the boundaries are quiet low usually, so dont worry youll be okay

You generally need over 85 for an A, which is pretty hard. This exam is absolutely horrific.

[master_blaster66]

(Original post by navarre)
You generally need over 85 for an A, which is pretty hard. This exam is absolutely horrific.

in f335 the highest ive seen is 84 or 85 but it can also go down to 80...and yes i agree, its the hardest exam by miles, but just hope we get a nice exam

[301lw]

(Original post by Ilyas)


can you see why now?

EDIT: You are actually correct, 4x10^-20 is correct. Look at the ms.




no. Raise it to the power of the mole, don't multiply.

of course! ah that's so silly of me, thanks for correcting me

[Iepnauy]

(Original post by master_blaster66)
the boundaries are quiet low usually, so dont worry youll be okay

I'm struggling to hit that A boundary

I dislike how pretty much every mark is extremely specific, it's not like biology where a 6 marker question can have 9 possible answers, in chemistry they want those exact 4 points (alternative wording). Oh well, more cramming to do tonight.

[navarre]

(Original post by master_blaster66)
in f335 the highest ive seen is 84 or 85 but it can also go down to 80...and yes i agree, its the hardest exam by miles, but just hope we get a nice exam

Same here mate. What we need are 5/6 markers on benzene AND colour, and a nice big question on buffers. If we get all three, I'm laughing.

BTW, for the electrophilic substitution of benzene with sulfur trioxide, what is everyone else putting? I know CGP revision guide says fuming sulfuric acid at 40oC, but that isn't in Chemical Ideas.

I'm just gonna stick with conc. sulfuric acid and heat under reflux methinks.

[master_blaster66]

(Original post by navarre)
Same here mate. What we need are 5/6 markers on benzene AND colour, and a nice big question on buffers. If we get all three, I'm laughing.

BTW, for the electrophilic substitution of benzene with sulfur trioxide, what is everyone else putting? I know CGP revision guide says fuming sulfuric acid at 40oC, but that isn't in Chemical Ideas.

I'm just gonna stick with conc. sulfuric acid and heat under reflux methinks.

im defo putting conc. sulfuric acid , heat under reflux for several hours

[Venomilys]

(Original post by master_blaster66)
in f335 the highest ive seen is 84 or 85 but it can also go down to 80...and yes i agree, its the hardest exam by miles, but just hope we get a nice exam

I've seen 90/120 for an A... luckily I got 94. And tbh it was actually a fairly standard paper!

[master_blaster66]

(Original post by Ilyas)
I've seen 90/120 for an A... luckily I got 94. And tbh it was actually a fairly standard paper!

hmm do you think :/...90/120? what paper was that

[Tamagotchi]

I have a question about entropy.

If we're talking about dissolving and crystallisation of salts, if we add more salt then this causes the entropy of the solution to increase because we're increasing the number of ions (and therefore the possible arrangement in space). But at the same time, the space in which the ions can be distributed decreases so the entropy decreases. So overall, what happens to the entropy?

If we just heat the solution so that the concentration rises but the number of ions stays the same then entropy decreases. What would have happen in the above scenario?

[Venomilys]

(Original post by Tamagotchi)
I have a question about entropy.

If we're talking about dissolving and crystallisation of salts, if we add more salt then this causes the entropy of the solution to increase because we're increasing the number of ions (and therefore the possible arrangement in space). But at the same time, the space in which the ions can be distributed decreases so the entropy decreases. So overall, what happens to the entropy?

If we just heat the solution so that the concentration rises but the number of ions stays the same then entropy decreases. What would have happen in the above scenario?

is this from a past paper? I would argue that the entropy increases. This idea of 'space' isn't really relevent, if you added more ions the size of the crystals will just increase proportionally, so technically number of arrangements increases.

Imagine if I added 1000^1000000000000 molecules of salt, they are not all going to fit into the crystal system, they will just expand the crystal system (the whole college would be packed with crystals).

that's just my opinion, I'm 99.99% sure they won't ask something of this nature.

[Venomilys]

(Original post by master_blaster66)
hmm do you think :/...90/120? what paper was that

june 2008 old spec (chem by design)

[SimpleGirl]

(Original post by navarre)
What we need are 5/6 markers on benzene AND colour, and a nice big question on buffers. If we get all three, I'm laughing.

That would actually be amazing.
But I have a feeling they're going to make it trickier and not just have those questions as 6 markers where everyone will write down everything they've memorised for past papers.

[ashleighlg]

Does anybody want to revise over MSN?

[Tamagotchi]

(Original post by Ilyas)
is this from a past paper? I would argue that the entropy increases. This idea of 'space' isn't really relevent, if you added more ions the size of the crystals will just increase proportionally, so technically number of arrangements increases.

Imagine if I added 1000^1000000000000 molecules of salt, they are not all going to fit into the crystal system, they will just expand the crystal system (the whole college would be packed with crystals).

that's just my opinion, I'm 99.99% sure they won't ask something of this nature.

What do you mean by the crystal system?

[master_blaster66]

(Original post by Ilyas)
I've seen 90/120 for an A... luckily I got 94. And tbh it was actually a fairly standard paper!

did you say the june06 paper was standard?

[navarre]

(Original post by SimpleGirl)
That would actually be amazing.
But I have a feeling they're going to make it trickier and not just have those questions as 6 markers where everyone will write down everything they've memorised for past papers.

Same, although the liklihood is is that they will do at least one out of benzene/colour/buffers. They've gotta give those 6 marks out somehow, and they can't do it asking what the systematic name for HCO₃^- is. There's only ever going to be a limited number of big mark questions they can ask, although they may change the wording and points in the mark scheme from year to year.

TBH, I'm revising stuff like GLC, dyes and carbon dioxide a great deal- there's a LOT of scope to go into detail on those topics, in a way I haven't seen in past papers.

[master_blaster66]

(Original post by navarre)
Same, although the liklihood is is that they will do at least one out of benzene/colour/buffers. They've gotta give those 6 marks out somehow, and they can't do it asking what the systematic name for HCO₃^- is. There's only ever going to be a limited number of big mark questions they can ask, although they may change the wording and points in the mark scheme from year to year.

TBH, I'm revising stuff like GLC, dyes and carbon dioxide a great deal- there's a LOT of scope to go into detail on those topics, in a way I haven't seen in past papers.

can you explain what youve learnt about glc?..that would be good