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Chemistry OCR AS F321 Atoms, Bonds and Groups May 2012

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Original post by Man-Utd
WE CAN DO IT......TOGETHER :biggrin:
lets help each other with tips ans stuff......
listen, the trick with chemistry is the balancing it with other subjects issue....sometimes, i find myself not focusing much on other subjects because of it


I think i need to do that too
Original post by scorpio22
lool sorry.Im a slow coach lool.

Okay...
1)what is a radical
2)state conditions for the formation of cl2 radicals
3)state the bond fission in the formation of cl2 radicals

each are one mark


its ok :wink:
1) a specie with unpaired electrons
2) u.v light
3) homolytic fission
Original post by otrivine
its ok :wink:
1) a specie with unpaired electrons
2) u.v light
3) homolytic fission


Excellent.the questions are going to get harder now:colone:
Butane c4h10 under certain conditions reacts with cl2 to form a mixture of chlorinated products.One possible product is c4h9cl.

c4h10+hcl---->c4h9cl + hcl

i state the conditions 1-mark

ii intiation

propagation =3 marks


write termination equation 1-mark


state the bond fission in intiation 1mark
(edited 11 years ago)
Original post by scorpio22
Excellent.the questions are going to get harder now:colone:
Butane c4h10 under certain conditions reacts with cl2 to form a mixture of chlorinated products.One possible product is c4h9cl.

c4h10+hcl---->c4h9cl + hcl

i state the conditions 1-mark
u.v light
ii intiation
cl2 to give 2 cl radicals
propagation =3 marks
- c4h10 + cl. - c4h9.+HCL
c4h9.+cl2 gives c4h9cl +cl.
write termination equation 1-mark
2 cl radicals to give cl2

state the bond fission in intiation 1mark


state the conditions 1-mark
u.v light
ii intiation
cl2 to give 2 cl radicals
propagation =3 marks
- c4h10 + cl. - c4h9.+HCL
c4h9.+cl2 gives c4h9cl +cl.
write termination equation 1-mark
2 cl radicals to give cl2

state the bond fission in intiation 1mark
homolytic
Original post by otrivine
state the conditions 1-mark



6/6 YOU ARE FLYING THROUGH:auto:!
Next Q.

1)c11h24,undercane can be separated by fractional distillation.
calculate the % compostion of carbon in undercane.(3marks)

2)Undercane can be cracked to nonane and compound A.
write a balanced equation for this reaction-2marks

3)name compound A-1 mark
(edited 11 years ago)
Original post by scorpio22
6/6 YOU ARE FLYING THROUGH:auto:!
Next Q.

1)c11h24,undercane can be separated by fractional distillation.
calculate the % compostion of carbon in undercane.(3marks)

2)Undercane can be cracked to nonane and compound A.
write a balanced equation for this reaction-2marks

3)name compound A-1 mark


1) mr of c11h24 = 156
do you need to crack the undercane to calculate ? tricky this one? can u show me
2) c11h24 - c9h20 +c2h4
3)ethene
Original post by otrivine
1) mr of c11h24 = 156
do you need to crack the undercane to calculate ? tricky this one? can u show me
2) c11h24 - c9h20 +c2h4
3)ethene


Hey,
you have the right idea.

you calculate the mr of Carbon in undercane
C x 11= 12x 11=132

and you already worked out c11h24=156

to find Carbons % cmpostion in undercane = 132/156 x 100 = 84.6 %


MARKS
you got 1 mark for working out mr 156.0.

2 marks for equation

1 mark for ethene
4/6 ...not bad
(edited 11 years ago)
Original post by scorpio22
Hey,
you have the right idea.

you calculate the mr of Carbon in undercane
C x 11= 12x 11=132

and you already worked out c11h24=156

to find Carbons % cmpostion in undercane = 132/156 x 100 = 84.6 %

i got it thanks :wink: easy!! and were the others correct?
Reply 128
Hi, just found this thread and thought I'd join in :smile:
Took this exam in January and retaking it :redface:
Found the exam really different to past papers, far more application, so at least I'll know what to expect this time :redface:
Original post by otrivine
i got it thanks :wink: easy!! and were the others correct?



The others were perfect


Propan-1-ol is refluxed to propanoic acid

1)state the colour change-2 mark

2)write a balanced equation with [o] in equation-2marks



3)using the period table/data sheethow does infrared confirm the presence of a carboxylic function group.
bond=
wavelegnth

bond=
wave legnth=

4marks
Original post by Gcayte
Hi, just found this thread and thought I'd join in :smile:
Took this exam in January and retaking it :redface:
Found the exam really different to past papers, far more application, so at least I'll know what to expect this time :redface:


yeah,the exam was a bit different from what i had revised
Original post by scorpio22
The others were perfect


Propan-1-ol is refluxed to propanoic acid

1)state the colour change-2 mark

2)write a balanced equation with [o] in equation-2marks



3)using the period table/data sheethow does infrared confirm the presence of a carboxylic function group.
bond=
wavelegnth

bond=
wave legnth=

4marks

1)orange to green
2) CH3CH2CH2OH +2(O) TO GIVE ch3ch2cooh +h20
3) cooh and wavelength is 2500-3300cm-1 (very broad)
Original post by otrivine
1)orange to green
2) CH3CH2CH2OH +2(O) TO GIVE ch3ch2cooh +h20
3) cooh and wavelength is 2500-3300cm-1 (very broad)


1=2/2

2=2/2

3=1/4

answer..
(If you look at the back of data sheet/period table given at college)..

We know that the product is propanoic acid therefore on the data sheet we look for the :
c=o bond which gives : 1640-1750 wavelegnth
o-h bond which gives : 2500-3500 wavelegnth

as they are both present in propanoic acid.
Original post by scorpio22
1=2/2

2=2/2

3=1/4

answer..
(If you look at the back of data sheet/period table given at college)..

We know that the product is propanoic acid therefore on the data sheet we look for the :
c=o bond which gives : 1640-1750 wavelegnth
o-h bond which gives : 2500-3500 wavelegnth

as they are both present in propanoic acid.


Snap! Yes oh dear can I have more please hey tomorrow shall we do bio unit 2 ?
Original post by otrivine
Snap! Yes oh dear can I have more please hey tomorrow shall we do bio unit 2 ?


Yh ill get more questions..
yh i definitely need to do bio unit 2...thats why im slow replying now i a having to do summaries.Just quick revision before i actually get into it.

A bit harder:colone:
1)define electrophille.
example
include in equation to show electophillic addition

2) define nuclephille
example
include equation to show nucleophilic substituion

3)define free radical
example
include example to show free radical substitution
(edited 11 years ago)
Original post by scorpio22
Yh ill get more questions..
yh i definitely need to do bio unit 2...thats why im slow replying now i a having to do summaries.Just quick revision before i actually get into it.

A bit harder:colone:
1)define electrophille.
example
include in equation to show electophillic addition

2) define nuclephille
example
include equation to show nucleophilic substituion

3)define free radical
example
include example to show free radical substitution


1) electrophile- accepts lone pairs of electron an example is mechanism with ethene with HBR for example to give ch3ch2br electrophilic addition.
2) nucleophile donates lone pairs of electron such as nucleophilic sub when an atom replaces another atom such as Hydrogen attacks carbon and the two electrosn are donated to chlorine
ch3ch2cl to gvie ch3ch3 +hbr
3) a species with unpaired electrons and free radical sub is where an atom is replaced by radicals such as the intitation ,propagation and termination and uv light needed
Original post by otrivine
1) electrophile- accepts lone pairs of electron an example is mechanism with ethene with HBR for example to give ch3ch2br electrophilic addition.

2) nucleophile donates lone pairs of electron such as nucleophilic sub when an atom replaces another atom such as Hydrogen attacks carbon and the two electrosn are donated to chlorine
ch3ch2cl to gvie ch3ch3 +hbr

3) a species with unpaired electrons and free radical sub is where an atom is replaced by radicals such as the intitation ,propagation and termination and uv light needed


1 =
-correct def,exam,eq

2=correct def...your example is wrong..im going to be a bit strict but H does not have lone pairs as it only has one election however :O-H does which is what i think you meant does.If the equation showed o-H instead of just H then you would be correct as the cl breaks away by hetrolyic fission whilst o-H bonds to the carbo cation



3= Correct definiton & example
Original post by scorpio22
1 =
-correct def,exam,eq

2=correct def...your example is wrong..im going to be a bit strict but H does not have lone pairs as it only has one election however :O-H does which is what i think you meant does.If the equation showed o-H instead of just H then you would be correct as the cl breaks away by hetrolyic fission whilst o-H bonds to the carbo cation



3= Correct definiton & example


Thanks so now I ask u but first can u tell me how I did overall what grade roughly ?
Original post by otrivine
Thanks so now I ask u but first can u tell me how I did overall what grade roughly ?


7/9 not bad,
gonna go now, wanna revise tommorow at 7/8?
(edited 11 years ago)
Original post by scorpio22
7/9 not bad,
gonna go now, wanna revise tommorow at 7/8?


So is 7/9 an A? Sure let's revise bio tomorrow :smile:

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