Yesss empirical formula means simplest whole number ratio though, so you can surely times your empiricals formula by 2 to get the MOLECULAR formula?

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yeah but they gave you the molcular mass of the compound... so you divide that value by the Mr of the empirical formula and it =1 so the compound they are asking for has no more than one O per molecule :smile:

Reply 4344

AAALIYAAAH

guys does anyone have the markscheme for yesterdays f322 chem exam :smile:

pls send the link if you do :smile:

Reply 4345

TheFootyKing19

Original post by AAALIYAAAH

guys does anyone have the markscheme for yesterdays f322 chem exam :smile:

pls send the link if you do :smile:

Unofficial MS: http://www.thestudentroom.co.uk/attachment.php?attachmentid=223281&d=1370370378

There's 2/3 mistakes in the document so take note.

Good luck

PS: it's not my MS - just reposting

Reply 4346

V__005

Original post by tomtjl

There was a peak for C-O, but you have to remember that the molecular formula was C4H8O, an ester would have had 2 Oxygens in it, therefore it must be an Aldehyde or Keytone.

Any unofficial mark scheme yet?

http://www.thestudentroom.co.uk/showthread.php?t=2372496 :smile:

There are a few errors maybe 1-2,but other than that,it's alright.

Reply 4347

V__005

Original post by Felttip

Where is the unofficial ms guys

http://www.thestudentroom.co.uk/showthread.php?t=2372496 :smile:

There are a few errors maybe 1-2,but other than that,it's alright.

Reply 4348

l2ob

Could someone explain to me that 'black smoke' answer? Because i thought you couldn't see CO so i thought it couldn't be Incomplet combustion :'( :'(

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Reply 4349

Clare224

Why would a ketone not count as a functional group?

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Reply 4350

dream996

Original post by l2ob

Could someone explain to me that 'black smoke' answer? Because i thought you couldn't see CO so i thought it couldn't be Incomplet combustion :'( :'(

Posted from TSR Mobile

I just put incomplete combusion since I don't know what else to put :tongue:

(I nearly forgot you can't see CO , that's a valid point actually!)

but if you see yellow flame that is DEFINITELY insufficient amount of oxygen supply!

Reply 4351

needtosucceed=)

Original post by Clare224

Why would a ketone not count as a functional group?

Posted from TSR Mobile

because there was a single bonded O next to it. whenever youve got COO its ester, because if it was a ketone then there would be a random 'o' next to it which has no functional group

Reply 4352

science-oliver

For the cracking on 1bi it didn't say use A (c15h32) so I put c7h16 and c8h16 will that give me the mark?

Reply 4353

Clare224

Oh I see! The thought never occurred to me, thank you!

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Reply 4354

science-oliver

Original post by l2ob

Could someone explain to me that 'black smoke' answer? Because i thought you couldn't see CO so i thought it couldn't be Incomplet combustion :'( :'(

Posted from TSR Mobile

It's because carbon and h20 can also be an incomplete combustion reaction and in this case carbon was produce ad solid carbon particles are soot :smile:

Reply 4355

Smko

Hey guys what is 37 or 36 in the Pratical ?
and what is around 95 in this exam?
UMS wise :smile:

(edited 10 years ago)

Reply 4356

needtosucceed=)

Original post by Smko

Hey guys what is 47 or 46 in the Pratical ?
and what is around 95 in this exam?
UMS wise :smile:

the practicals are out of 40 so im not sure how you got 46
95 would probably be full ums.

Reply 4357

Smko

Original post by needtosucceed=)

the practicals are out of 40 so im not sure how you got 46
95 would probably be full ums.

Sorry Sorry meant 37 :P Not 46/47 sorry!

Reply 4358

xT4Z1N4TRx

how much was the last question worth? its cut off on the document

Reply 4359

wndms

Original post by l2ob

Yesss empirical formula means simplest whole number ratio though, so you can surely times your empiricals formula by 2 to get the MOLECULAR formula?

Posted from TSR Mobile

Molecular was the same as emperical