OCR A2 CHEMISTRY F324 and F325- 14th and 22nd June 2016- OFFICIAL THREAD

trans fats are potentially more damaging than saturated fats as they not only increase ldl levels but they reduce hdl levels according to the spec. I think you could get either fatty acid 1 or 3 depending on your explanation both can be argued

So do trans fatty acids? why are you in denial? trans fatty acids increase LDL and it is likely that the third will have a trans bond that's all I am saying.

Both for 3marks.

explain that condensation polymers:
(i) may be photodegradable as the C=O bond absorbs radiation,
(ii) may be hydrolysed at the ester or amide group.

YES, TRANS FATTY ACIDS ARE INCREASE LDL LEVELS - NO ONE IS DENYING THAT IF YOU PAY ATTENTION TO WHT EVERYONE ELSE IS WRITING. What we are saying is that the SATURATED FAT - THE FIRST ONE - WILL GUARANTEE FORM A SATURATED FATTY ACID WHICH IS BAD. THE THIRD FATTY ACID MAY OR MAY NOT FORM A TRANS FAT, WHICH IS ALSO BAD, BUT WE CAN'T TELL AND IT'S MORE LIKELY TO BE A CIS FAT BECAUSE THE QUESTION SAID NATURALLY FORMING FATTY ACIDS FOR A REASON AND NATURALLY FORMING FATTY ACIDS ARE USUALLY CIS AND SO WILL FORM CIS FATS.

i totally missed out the photodegradable part as i thought the stitches are too small to absorb radiation. all i write after saying that PLA could be hydrolyse is that lactic acid is a liquid, so the stitches would just flow away and dissolve lol, sounds so stupid but i cannot think of other answer.

Both for 3marks.

explain that condensation polymers:
(i) may be photodegradable as the C=O bond absorbs radiation,
(ii) may be hydrolysed at the ester or amide group.

So do trans fatty acids? why are you in denial? trans fatty acids increase LDL and it is likely that the third will have a trans bond that's all I am saying.

Hahaha don't stress, I managed to remember the photodegradable bit, but not the hydrolysis - I'm a mess.

Just going to add to this personally I don't think photodegradable is right because it specifically says in text book "c=o absorbs uv radiation when contained in polymer 'backbone'" but this c=o bond wasn't in the backbone so isn't photodegradable...

So do trans fatty acids? why are you in denial? trans fatty acids increase LDL and it is likely that the third will have a trans bond that's all I am saying.

so let's say each hydrolysis and photodegradable for 1, what would be the last point for.

Regarding the dissolvable stitches: C=O absorbs infrared radiation which causes it to be broken down into CO2 and H2O as its biodegradable.

I'm not sure of the marking points but the C=O absorbing IR radiation is mentioned on the spec.

1 /5char?

I can't imagine how hydrolysis would be three marks, that's why I personally think its a viable answer and most likely will be credited for in the markscheme. But I defo agree.

Just going to add to this personally I don't think photodegradable is right because it specifically says in text book "c=o absorbs uv radiation when contained in polymer 'backbone'" but this c=o bond wasn't in the backbone so isn't photodegradable...

Photodegradable --> broken down into CO2 and H2O -MAYBE?