Edexcel Chemistry A2 Unit 5 ~ Wednesday 19th June 2013 (Now Closed) Watch

Poll: How pumped up are you for this exam?-(warning)-(bad jokes arene this poll!)
"Titanium-I'm not going to corrode (even at high temperatures)" (A*) (22)
16.67%
"Benzene's my middle name, give me the paper in a week and I'll ace it!" (A) (27)
20.45%
"Yeah, I'm fairly electrophillic (positively charged) about the exam" (B) (27)
20.45%
"I'm in the middle of the salt bridge, but I will pass-eventually" (C) (21)
15.91%
"I'm feeling rather electroNegative about this exam" (D) (18)
13.64%
"Benzene, what's that?" (E) (6)
4.55%
"Chemistry, what's that?" (F) (11)
8.33%
This discussion is closed.
jojo1995
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#1481
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#1481
(Original post by AS01)
the only thing that becomes part of ring is the group directly attached to it others dont really contribute electron to the pi system. Having said that with ethylbenzene the CH3 group pushes electron cloud to CH group attached to benzene so activates the ring as e- density increases
ahh okay ... thank you - I didnt know that before - *sad times*
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AS01
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#1482
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#1482
(Original post by jojo1995)
ahh okay ... thank you - I didnt know that before - *sad times*
Now you do
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shumen9523
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#1483
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#1483
(Original post by AS01)
I have answer to your question
The thing is zwitterions doesnt exist alone. Remember there is reversible reaction between amino acid and zwitterion so peptide bond forms with amino acids only as they are also present
Yeah, it makes sense now
Thanks A LOT ... and good luck with Chem 5
EDIT: I can't (+ rep) you now but I will once I rate other members
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AS01
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#1484
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#1484
(Original post by shumen9523)
Yeah, it makes sense now (+rep)
Thanks A LOT ... and good luck with Chem 5
Thank you. Good luck to you too! Hope the paper is good
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Knoyle quiah
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#1485
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#1485
(Original post by AS01)
yeah u have round bottom flask with the reactants in another flask u have water or something that boils at a temp lower than boiling point of phenylamine. Now the steam from this flask to the flask where there are reactants which will heat the reactants on that flask coz when the steam condenses it releases heat which will be enough to heat the reactants.
Phenylamine and water will evaporate and is condensed by the condenser since they are immiscible they would form two layers which could be separated using a separating funnel.
Phenylamine does react slightly with water so when separating using separating funnel u have to dissolve it in NaCl to reduce solubility of phenylamine in water so that u dont lose ur product and get high yield.
Hope it helped
Thank you for a very clear explanation all makes sense but when and where is the NaCL added??
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AS01
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#1486
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#1486
(Original post by Knoyle quiah)
Thank you for a very clear explanation all makes sense but when and where is the NaCL added??
After u do steam distillation u have product with mixture of water and phenylamine right?
u wanna get rid of water so what u do is add NaCl and keep in separating funnel. I think aq layer will be below and organic layer at the top so u can get rid of aq layer by opening the tap. After than u have organic layer left which will still have water in it. So what u need to do next is add anhydrous Na2CO3 why this and not CaCl2 is coz CaCl2 and magnesium sulphate will react with phenylamine. So now water will be removed but then again u have sodium carbonate in ur product so u decant the product and then distil the solution to get phenylamine in pure form.
lol I think I explained more than what u asked for
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jojo1995
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#1487
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#1487
(Original post by AS01)
Now you do

I certainly do



ATM ... I'm really bad at hydrogen environments

couls someone help me out please --- i did a drawing on paint and i was wondering if anyone could tell me if im right in circling different hydrogen environewmnts in different circles ?
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Weaselmoose
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#1488
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#1488
(Original post by LeaX)
Can [Cu(NH3)6]2+ form? I've seen in most textbooks and websites that only [Cu(NH3)4]2+ can form but in Jan 2013 for the transition metals question (14, a, C) it says [Cu(NH3)6]2+ as a potential answer?
In theory it can but only doesn't because the ammonia Ligands are slightly bigger than water Ligands so they can't fit around the Cu if there's 6.
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Bord3r
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#1489
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#1489
(Original post by jojo1995)
I certainly do



ATM ... I'm really bad at hydrogen environments

couls someone help me out please --- i did a drawing on paint and i was wondering if anyone could tell me if im right in circling different hydrogen environewmnts in different circles ?
Looks right to me.
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AS01
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#1490
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#1490
(Original post by jojo1995)
I certainly do



ATM ... I'm really bad at hydrogen environments

couls someone help me out please --- i did a drawing on paint and i was wondering if anyone could tell me if im right in circling different hydrogen environewmnts in different circles ?
I think there are only 3 hydrogen environment. One on each of those methyl group one on C next to methyl group on both side and another is all H in those CH2 group after CH3CH2 on both side
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Weaselmoose
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#1491
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#1491
(Original post by jojo1995)
I certainly do



ATM ... I'm really bad at hydrogen environments

couls someone help me out please --- i did a drawing on paint and i was wondering if anyone could tell me if im right in circling different hydrogen environewmnts in different circles ?
As far as I remember, the three CH2 environments in the middle are all the same as they are all surrounded by a CH2 on either side so they are only counted as 1 environment
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AS01
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#1492
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#1492
(Original post by Bord3r)
Looks right to me.
no there are only 3 environments. all those CH2 groups next to CH3CH2 are counted as one and two methyl on opposite end as one and H is CH2 next to methyl group on both side
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F1's Finest
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#1493
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#1493
(Original post by LeaX)
Can [Cu(NH3)6]2+ form? I've seen in most textbooks and websites that only [Cu(NH3)4]2+ can form but in Jan 2013 for the transition metals question (14, a, C) it says [Cu(NH3)6]2+ as a potential answer?


(Original post by Weaselmoose)
In theory it can but only doesn't because the ammonia Ligands are slightly bigger than water Ligands so they can't fit around the Cu if there's 6.
Steric Hinderance, pretty much what Weaselmoose said
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jojo1995
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#1494
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#1494
(Original post by AS01)
I think there are only 3 hydrogen environment. One on each of those methyl group one on C next to methyl group on both side and another is all H in those CH2 group after CH3CH2 on both side

(Original post by Bord3r)
Looks right to me.

(Original post by Weaselmoose)
As far as I remember, the three CH2 environments in the middle are all the same as they are all surrounded by a CH2 on either side so they are only counted as 1 environment
you see in the jan 2013 finAL question ... i tried your approach but i got the answer wrong


thank you all guys for your responses ... i thought the same as you guys ... it seems you all have dfifferent opinions
i am so confused :?
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AS01
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#1495
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#1495
(Original post by jojo1995)
you see in the jan 2013 finAL question ... i tried your approach but i got the answer wrong


thank you all guys for your responses ... i thought the same as you guys ... it seems you all have dfifferent opinions
i am so confused :?
Nope it does work by this way
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jojo1995
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#1496
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#1496
(Original post by AS01)
no there are only 3 environments. all those CH2 groups next to CH3CH2 are counted as one and two methyl on opposite end as one and H is CH2 next to methyl group on both side
Oh okay, are there 5 h environments then ?
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jojo1995
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#1497
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#1497
(Original post by AS01)
Nope it does work by this way
but there are 2 sets of 4 sets of ch2 groups down the bottom of the molecule,... i though they were all in one h envionment but it turns out there are 2 ... i dont get why though

becuase the 4 ch2 groups are all attatched to a ch2 group and a ch group so idk
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AS01
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#1498
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#1498
(Original post by jojo1995)
Oh okay, are there 5 h environments then ?
no no just 3. The one marked with same colour are one H environment
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Lastminutepanic
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#1499
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#1499
In the specification it says 'describe and carry out, where appropriate, the preparation of a compound, eg cholesteryl benzoate (a liquid crystal) and of methyl 3-nitrobenzoate, requiring some of the following techniques...' Do we need to know how to make cholesteryl benzoate and methyl 3-nitrobenzoate or just how to carry out the different techniques??
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AS01
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#1500
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#1500
(Original post by jojo1995)
but there are 2 sets of 4 sets of ch2 groups down the bottom of the molecule,... i though they were all in one h envionment but it turns out there are 2 ... i dont get why though

becuase the 4 ch2 groups are all attatched to a ch2 group and a ch group so idk
if u look at the one which is projectiong out its in same environment as the one just below is coz they both are bonded to same group. Again if u look at another CH2 at the top plane t it is bonded to same groups as the one which is at the corner of the plane below. so they are in same environment
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