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Chemistry Unit 2 Edexcel, Exam- 23rd May 2012

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Reply 940

Arusa01

Original post by Blob2491

You too!

(although you don't need it!)

Trust me I do :frown:

Haa.

Reply 941

GreeseMonkey

yo guys i got some problem with the yield and pressure..i dont really get the relation between yield ,rate,temperature and pressure..
like one of the questions....mcq number 10 june 09 paper..

Reply 942

EffKayy

Original post by Arusa01

Trust me I do :frown:

Haa.

Some pos rep to make you feel better :wink:

LOL you're going to flipping ace it now go revise xoxo

Reply 943

Arusa01

Original post by EffKayy

Some pos rep to make you feel better :wink:

LOL you're going to flipping ace it now go revise xoxo

I'm gonna BOSSS it.

No. ok.

Reply 944

qwerasd1

Original post by GreeseMonkey

yo guys i got some problem with the yield and pressure..i dont really get the relation between yield ,rate,temperature and pressure..
like one of the questions....mcq number 10 june 09 paper..

a) cause ∆H is negative for the forward reaction increasing temp means equilibrium will shift to the left meaning less yield (products) but the rate will increase cause particles have more energy and can overcome the activation energy

(edited 11 years ago)

Reply 945

qwerasd1

Original post by GreeseMonkey

yo guys i got some problem with the yield and pressure..i dont really get the relation between yield ,rate,temperature and pressure..
like one of the questions....mcq number 10 june 09 paper..

b) Decreasing pressure causes equilibrium to shift to the left cause there are more moles of gas so yield will decrease and rate decreases as decreasing pressure is like decreasing conc so less likely for particles to collide

Reply 946

GreeseMonkey

Original post by qwerasd1

thanks

Reply 947

Lightuponlight

Everyone asleep? =P

Its a new day feel fresh and pray all goes well iA :biggrin:

BTW chemistry unit2 exam is afternoon session right??? PM?

BEST OF LUCK EVERY1ONE :biggrin:

Reply 948

phaseshift

Original post by Lightuponlight

Everyone asleep? =P

Its a new day feel fresh and pray all goes well iA :biggrin:

BTW chemistry unit2 exam is afternoon session right??? PM?

BEST OF LUCK EVERY1ONE :biggrin:

Nah, can't sleep. The sandman simply doesn't like me at the moment!

It is a PM exam yes. :smile:

Reply 949

username714290

Do not want to do this exam, revising for it is too much for me :cry:

Reply 950

phaseshift

Original post by iLoveRobSwire<3

Do not want to do this exam, revising for it is too much for me :cry:

There there, just power on through and you'll do fine! :biggrin:

Reply 951

username714290

Original post by HarryMWilliams

There there, just power on through and you'll do fine! :biggrin:

Seriously, chem is my worst subject and I can't wait to drop it after this exam. I'm trying to get a decent grade but I just can't be bothered to revise :frown:

Reply 952

cisne

Need to remember all this.....

Reactions of alcohols:
1. Reaction with water

2. Reaction with alkali metals

3. Reaction with alkali solution

4. Reaction with carbonates & hydrogen carbonates

5. Oxidation of alcohols

6. Reaction with dehydrating agents

7. Reaction with halogenating agents
i) reaction with PCl5(s)
ii) reaction with PX3(l) (X=Cl,Br,I)
iii) reaction with moist red phosphorous and liquid bromine
iv) reaction with moist red phosphorous and solid iodine
v) reaction with KBr(s) and conc H2SO4 (l)

8. Reaction with alkali iodine

9. Esterification reaction

10. Combustion

(edited 11 years ago)

Reply 953

Ataraxian-Walker

Does anyone have extra questions on Chem Unit 2?

Reply 954

verdikt

Original post by Ataraxian-Walker

Does anyone have extra questions on Chem Unit 2?

I think the only worse thing we can hope for are apparatuses. They seem to be the only worse thing in most of these papers.

Reply 955

PoeMar

Like everyone's fell asleep already. Good Luck for Chemistry Unit 2 Edexcel exam this afternoon. Sleep well, have sweet dream b4 getting into the hell. Oh i mean hall. :colondollar:

Reply 956

salvequamtu

Does tertiary alcohol reactions (Sn1) not have a transition state... like the Sn2 reactions??

Reply 957

VRS

Original post by AmrinderRai

Does tertiary alcohol reactions (Sn1) not have a transition state... like the Sn2 reactions??

Correct!

Sn1 requires a carbocation

Sn2 is a straight simultaneous swap, as compounds that rely on sn2 are less stable

This was posted from The Student Room's iPhone/iPad App

Reply 958

YellowAndBlack

Original post by VRS

Correct!

Sn1 requires a carbocation

Sn2 is a straight simultaneous swap, as compounds that rely on sn2 are less stable

This was posted from The Student Room's iPhone/iPad App

Sn2 also requires a carbocation

Sn1
And is also techniqually a swap
You break off the C-Halogen bond for example - Let's say bromine = Forming a carbocation
A :Nu (nucleophile) attacks and attachs onto this carbocation - bromine is a product

And for Sn1 why are they less stable?

Reply 959

salvequamtu

Original post by VRS

Correct!

Sn1 requires a carbocation

Sn2 is a straight simultaneous swap, as compounds that rely on sn2 are less stable

This was posted from The Student Room's iPhone/iPad App