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.
blackraven
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#1861
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#1861
Whoever George Lewis is, thank you for those notes!! seriously they are spectacular.
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blackraven
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#1862
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#1862
(Original post by AtomicMan)
When would you use steam distillation?

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to separate organic products which might otherwise decompose from sustained heating.
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Bord3r
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#1863
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#1863
(Original post by blackraven)
Whoever George Lewis is, thank you for those notes!! seriously they are spectacular.
Second this. Brilliant notes.
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F1's Finest
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#1864
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#1864
(Original post by AtomicMan)
When would you use steam distillation?

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To prevent a compound from decomposing when heated up.

In other words, we're able to distil a product at a lower temperature than it's boiling point. Extremely useful if we want to maximise the product yield.
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AtomicMan
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#1865
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#1865
(Original post by Bord3r)
Second this. Brilliant notes.
Link please?

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jojo1995
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#1866
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#1866
(Original post by posthumus)
But the option said aq ammonia or does that no have much significance ?

& Thank-you
Yeah aq ammonia is what the reactions take place with Ccording to the edexcel blue book.... No problem
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F1's Finest
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#1867
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#1867
How do you know if a product shows optical activity? Is that if it contains a chiral carbon?
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jojo1995
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#1868
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#1868
(Original post by Bubblezzzz)
Good luck everyone! X
hope you all get a*s
Aren't you lovely ... I hope we all do too
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jojo1995
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#1869
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#1869
(Original post by James A)
How do you know if a product shows optical activity? Is that if it contains a chiral carbon?
No, you use a polarimeter to test whether it rotates the plane of polarisation of plane polarised light. If it does it is optically active

Edit; yes that is actually, but it's not a test for it
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F1's Finest
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#1870
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#1870
(Original post by jojo1995)
No, you use a polarimeter to test whether it rotates the plane of polarisation of plane polarised light. If it does it is optically active

Edit; yes that is actually, but it's not a test for it
So does that mean a racemic mixture is optically active?
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posthumus
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#1871
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#1871
(Original post by James A)
So does that mean a racemic mixture is optically active?
racemic solution contained same amount of both enantiomers which rotate plane polarised light in opposite directions equally...

since they're in equal amounts there will be no optical activity of the mixture as a whole
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randyaloul
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#1872
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#1872
(Original post by James A)
How do you know if a product shows optical activity? Is that if it contains a chiral carbon?

No, it might have a chiral carbon but it might be a racemic mixture, in that case it's not optically active. All optically active substances have chiral carbon atoms, but not all molecules with chiral carbon atoms are optically active. If that makes any sense
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jojo1995
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#1873
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#1873
(Original post by James A)
So does that mean a racemic mixture is optically active?
No a race mic mixture isn't as although each isomer would rotate the ppl, they would do so in opposite directions and so they cancel out. So race mic mixture had no overall effect on ppl
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alla soup
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#1874
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#1874
Does anyone have a link for jan 2013 mark scheme ?
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Gnome :)
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#1875
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#1875
(Original post by James A)
How do you know if a product shows optical activity? Is that if it contains a chiral carbon?
Stumbled across this wonderful video earlier: http://www.khanacademy.org/science/o...n-to-chirality. The example videos are pretty useful. A Chiral molecule will rotate the plane of plane polarised light.
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F1's Finest
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#1876
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#1876
Cheers everyone :yy: I got it now xD
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blackraven
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#1877
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#1877
(Original post by alla soup)
Does anyone have a link for jan 2013 mark scheme ?
attached
Attached files
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blackraven
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#1878
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#1878
(Original post by AtomicMan)
Link please?

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I feel obligated to share them. I'm so happy i stumbled upon them
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Knoyle quiah
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#1879
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#1879
solvent extraction : you add something that the product your after dissolves in but waste doesnt, and then what happens after this i dont understand, someone please explain
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I Hate Edexcel
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#1880
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#1880
I've given up aiming for an A* in this... it's too hard.
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