Aqa chem4 15th june 2011 (resit) thread

Original post by Zakir

Oh ok...
Yeh thats what i got...the bromosomething purple and yellow, thats gd! :smile:

Did you put purple AND yellow or purple TO yellow? Cos' it said colour change? :s-smilie:

Reply 1041

bjparmar

Original post by sam_xo

Did you put purple AND yellow or purple TO yellow? Cos' it said colour change? :s-smilie:

i put between purple and yellow omggggggggggggggg fail ahahaha

Reply 1042

Zakir

Original post by T-Toe

I got bromosomething too.

What did you get for molecular ion? m/z=177?

i got C6H5(BENZENE)COOCH2CH3 with another CO on the other branch and the free radical was OCH2CH3 < realised when i was checking through my work that i missed the 'O' so corrected it in time...

what about you?

Reply 1043

Original post by Zakir

i got C6H5(BENZENE)COOCH2CH3 with another CO on the other branch and the free radical was OCH2CH3 < realised when i was checking through my work that i missed the 'O' so corrected it in time...

what about you?

I did all that but accidently inculded another O to the molecular ion :mad:

ffs

Reply 1044

Original post by bjparmar

i put between purple and yellow omggggggggggggggg fail ahahaha

LOL No don't go off what I say! You might be right :smile:

Reply 1045

Original post by sam_xo

LOL No don't go off what I say! You might be right :smile:

You are right.

*awkward silence*

How many marks was that question?

Reply 1046

Zakir

Original post by T-Toe

I did all that but accidently inculded another O to the molecular ion :mad:

ffs

ohhh ok...mistakes happen, specially under exam pressure...

Reply 1047

Original post by T-Toe

You are right.

*awkward silence*

How many marks was that question?

It was 1 mark wasn't it? :smile:

Reply 1048

Original post by sam_xo

It was 1 mark wasn't it? :smile:

I could've sworn it was 2 marks.

Reply 1049

Original post by T-Toe

I could've sworn it was 2 marks.

Wasn't it 1 for the indicator then 1 for the colour? I'm sure it was one. Lol plus I don't think that type of question would be 2 anyway. Similar questions in some of the past papers from the old spec award 1 mark :smile:

Reply 1050

Original post by sam_xo

Wasn't it 1 for the indicator then 1 for the colour? I'm sure it was one. Lol plus I don't think that type of question would be 2 anyway. Similar questions in some of the past papers from the old spec award 1 mark :smile:

Niice, 1 mark ain't no biggy then :smile:

Reply 1051

Original post by T-Toe

Niice, 1 mark ain't no biggy then :smile:

Yep

Unlike the 6 mark one I got COMPLETELY wrong. Lol :frown:

Reply 1052

Original post by sam_xo

Yep

Unlike the 6 mark one I got COMPLETELY wrong. Lol :frown:

Benzen ene benzene is -120kj mol-1
so we'd assumed that a benzene triene would be -360KJ mol-1 (3x-120)
However benzene have a enthaply change of about -220 KJ mol-1 (forget the exact enthaply change)

Therefore benzene is more stable than benzene triene.

Did you mention any of this? :smile:

It was 6 marks and I'm not sure what else to add..so I also think I've lost marks too :|

edit - I added equations too

(edited 12 years ago)

Reply 1053

JK471993

Damn! I just realised I put Na2CO3, not NaH!

Reply 1054

Original post by JK471993

Damn! I just realised I put Na2CO3, not NaH!

for what?

Reply 1055

Original post by Ramses II

I did NaHCO3 for the acid, causing CO2 effervescence.
For the Acyl chloride, there is a vigorous reaction and white precipitate with AgNO3.
Primary alcohol I did acidified K2Cr2O7, orange to green.

I didn't say vigorous reaction, just white preciptate is formed will I lose the mark?

Reply 1056

JK471993

Original post by T-Toe

for what?

The test for carboxylic acids. Nevermind. I still described the observations :smile:

Reply 1057

shak2345

Original post by T-Toe

Benzen ene benzene is -120kj mol-1
so we'd assumed that a benzene triene would be -360KJ mol-1 (3x-120)
However benzene have a enthaply change of about -220 KJ mol-1 (forget the exact enthaply change)

Therefore benzene is more stable than benzene triene.

Did you mention any of this? :smile:

It was 6 marks and I'm not sure what else to add..so I also think I've lost marks too :|

edit - I added equations too

The enthalpy of hydroegnation of benzene was more stable due to the identical carbon-carbon bonds in benzene, meaning there is an unused p orbital.

There are 6 delocalised electrons in benzene, which therefore increases the stability of benzene due to the increased delocalisation energy it exhibits.

Reply 1058

Ramses II

8

Original post by T-Toe

I didn't say vigorous reaction, just white preciptate is formed will I lose the mark?

I doubt it :smile:

. That is just a hunch though.

Reply 1059