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OCR Chemistry B F331 Chemistry for Life (13-01-2012)

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Reply 340

mycollege

for the graph question, did everyone get 4000???

Reply 341

Zhy

Original post by Bellissima

i think this is right tbh... it's not what i put but they are the functional groups, ether/alkene are the homogoulous groups (can't spell)

Why? I thought homologous series were basically series which you could group certain compounds in that have a general formula. For example, cycloalkanes is a homologous series but I'm not sure it's a functional group.

Reply 342

Bellissima

Original post by Zhy

My teacher said that if I got full marks he was buying everyone lunch! Arghhhh people are going to be so annoyed at me.

I am pretty sure I got an A. But definitely not full marks now. Will be lucky to get 58/60.

maybe you should stop putting so much pressure on yourself i mean what are you going to do if you don't get an A, kill yourself? i seriously doubt whether people will care what grade you got either.

Reply 343

Jammy4410

Original post by mycollege

for the graph question, did everyone get 4000???

YEP and you had to show how so i just extended the first line

Reply 344

Zhy

Original post by Jammy4410

47/60 a
43/60 or 44/60 b

Hmm, that would mean 90% is either 50 or 51 and 100% is either 53 or 55...

Reply 345

AGrumpyMole

Original post by aim28

0.36cm^3

To 2 significant figures, as it asked, it' 0.4cm^3.

Oh, damn, sorry :[

(edited 12 years ago)

Reply 346

Bellissima

Original post by Zhy

I got C21H44 too.

For cycloalkane I immediately said whatever one was C22H44... which could also be an alkene... but apparently you were supposed to write two letters? Ugh...

no i am pretty sure it said ONE in bold, the only one where you had to put 2 was which TWO were isomers

Reply 347

Roshniroxy

Original post by Zhy

Why higher than usual? What do you predict for an A?

I'd say no higher than 50/60 is an A, would be just a pisstake if they set 53 or 54 as an A.

well the Jan 2011 paper for one was harder than our paper, it had more questions that people could lose marks on especially the first question, and the graph question etc. On the other hand our paper was much simple, I don't think there was any question that was very hard or couldn't be answered (except the moles ratio one)

I think the boundaries will be 52/53

Reply 348

Zhy

Original post by AGrumpyMole

To 2 significant figures, as it asked, it' 0.4cm^3.

No, that's 1 sig fig. It's 0.36 to 2 s.f.

Reply 349

Bellissima

GUYS - for the functional group question - ether and alkene are not functional groups are they? they are homogoulous groups or however you spell it... like alcohols.. the functional group is the OH, not the word alcohol????

Reply 350

Zhy

Original post by Bellissima

maybe you should stop putting so much pressure on yourself i mean what are you going to do if you don't get an A, kill yourself? i seriously doubt whether people will care what grade you got either.

People do care, honestly... they have repeatedly informed me of the marks I got in previous exams and it was really annoying. I'm happy with an A (90%+ is preferable) but others will be shocked.

Reply 351

Roshniroxy

Original post by Jammy4410

i wrote number of protons.
If you wrote exactly what you typed now you probably wouldn't get mark as it could easily be interpreted as Protons + electrons

I wrote protons then I wrote electrons, then I wrote a sentence explaining how I don't mean the sum of the protons and electrons just them individually.

Reply 352

mycollege

Original post by Zhy

No, that's 1 sig fig. It's 0.36 to 2 s.f.

thats what I put!

Reply 353

Bellissima

Original post by Zhy

say you had butanol... is is in the alcohol homogulous series... but the functional group is the OH... if you were asked what the functional group of butanol was, you would put OH not "alcohol"... so for cycloalkane the carbon ring would be the func group and for ether the oxygen in middle of C chain would be func group and for alkene the double covalents would be func gorup.

this is just what i think i may be wrong.

Reply 354

Jammy4410

Original post by Bellissima

True but i reckon they will be kinda lenient i reckon if you put hom/ser you will get 1/2

Reply 355

AGrumpyMole

Original post by Zhy

109 degrees. There is proof on Wikipedia, search for octasulfur...

Is it not 104.5 as there were 2 lone pairs and each lone pair repels 2.5 degrees approximately? The mark scheme will say a range of 104 - 109 most likely though as they usually do :smile:

Reply 356

Bellissima

Original post by Zhy

People do care, honestly... they have repeatedly informed me of the marks I got in previous exams and it was really annoying. I'm happy with an A (90%+ is preferable) but others will be shocked.

forget about them you are all that matters when it comes to your own grades

Reply 357

Zhy

Original post by AGrumpyMole

Is it not 104.5 as there were 2 lone pairs and each lone pair repels 2.5 degrees approximately? The mark scheme will say a range of 104 - 109 most likely though as they usually do :smile:

Yes but you don't need to know that for this specification. Most candidates will say 109 degrees.

Reply 358

Bellissima

Original post by AGrumpyMole

Is it not 104.5 as there were 2 lone pairs and each lone pair repels 2.5 degrees approximately? The mark scheme will say a range of 104 - 109 most likely though as they usually do :smile:

yes it is that but rev guides vary so 104-109 is acceptable.