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OCR Salters F334 Chemistry of Materials (26/01/2011)

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Reply 100
Avatar for AAAAA1
AAAAA1
I am 13 yrs old and taking the exam! :biggrin:
Original post by AAAAA1
I am 13 yrs old and taking the exam! :biggrin:


lol. either you're trolling or you're just outrageously intelligent
Reply 102
Avatar for danman14
danman14
1
how much detail do we need to know with extracting metal ores? all i can find in my notes is that:
a) reactive group 1 & 2 metals are extracted by electrolysis
b) less reactive metals obtained from their ores by reduction with carbon/carbon monoxide
c) unreactive metals are found as elements in the earths crust.
Reply 103
Avatar for SarahPops
SarahPops
Can anyone answer this for me please, its doing my head in and i'm not gunna see my chemistry teacher before the exam!? Its probably a really stupid question but.....

In the acid and alkali hydrolysis of peptides/proteins what are the products?

In my book it says for acid --> the -NH2 groups are protonated to become NH3 which i think is an ammonium ion? Then for Alkali hydrolysis the -COOH is deprotonated to give carboxylate anions?

Is this right and are both products the same (i.e for acid hydrolysis both products are ammonium ions)?

Also it says to identify amino acids from the hydrolysis use thin layer chromotogrophy - can the -NH3 and -COO- products still be identified as amino acids??

Thats all any help would be greatly appreciated :smile:
Original post by SarahPops
Can anyone answer this for me please, its doing my head in and i'm not gunna see my chemistry teacher before the exam!? Its probably a really stupid question but.....

In the acid and alkali hydrolysis of peptides/proteins what are the products?

In my book it says for acid --> the -NH2 groups are protonated to become NH3 which i think is an ammonium ion? Then for Alkali hydrolysis the -COOH is deprotonated to give carboxylate anions?

Is this right and are both products the same (i.e for acid hydrolysis both products are ammonium ions)?

Also it says to identify amino acids from the hydrolysis use thin layer chromotogrophy - can the -NH3 and -COO- products still be identified as amino acids??

Thats all any help would be greatly appreciated :smile:


I don't know about acid and alkali hydrolysis but I know that when acid is added to the amino acid and the PH is below its isoelectric point the NH2 is protonated and when the PH is above the isoelectric point the COOH loses a proton.
Reply 105
Avatar for SarahPops
SarahPops
Original post by jam277
I don't know about acid and alkali hydrolysis but I know that when acid is added to the amino acid and the PH is below its isoelectric point the NH2 is protonated and when the PH is above the isoelectric point the COOH loses a proton.


Oh yeah that is for acid base reactions involving amino acids (as they are amphoteric so can act as either an acid or a base) that iis in the same section that i am studying but not eactly what i was looking for.

Thanks for replying anyway :smile:
Original post by SarahPops
Can anyone answer this for me please, its doing my head in and i'm not gunna see my chemistry teacher before the exam!? Its probably a really stupid question but.....

In the acid and alkali hydrolysis of peptides/proteins what are the products?

In my book it says for acid --> the -NH2 groups are protonated to become NH3 which i think is an ammonium ion? Then for Alkali hydrolysis the -COOH is deprotonated to give carboxylate anions?

Is this right and are both products the same (i.e for acid hydrolysis both products are ammonium ions)?

Also it says to identify amino acids from the hydrolysis use thin layer chromotogrophy - can the -NH3 and -COO- products still be identified as amino acids??

Thats all any help would be greatly appreciated :smile:


Yeah both the products of hydrolysis are the same just alter according to whether it's acid or alkaline hydrolysis i'm not sure about the thin layer chromatography but im sure that they would still show up as amino acids despite the charged groups :smile:
Reply 107
Avatar for SarahPops
SarahPops
Original post by Ch-Ch-Charlie
Yeah both the products of hydrolysis are the same just alter according to whether it's acid or alkaline hydrolysis i'm not sure about the thin layer chromatography but im sure that they would still show up as amino acids despite the charged groups :smile:


Thank you so much!!!! My mind is put at ease!!!
Original post by SarahPops
Oh yeah that is for acid base reactions involving amino acids (as they are amphoteric so can act as either an acid or a base) that iis in the same section that i am studying but not eactly what i was looking for.

Thanks for replying anyway :smile:


What you're saying makes sense though, But in the CGP book it says that to hydrolyse a protein you need 6moldm^-3 sulfuric acid and it needs to be heated for 24 hours.
Reply 109
Avatar for cORBO3
cORBO3
Can anyone confirm if we need to know anything about BOS? I been through the spec, and it dosen't include BOS, my revison guide also dosen't meantion BOS.

But my teacher says we need to know it.
its in the storylines SS bit

and in the end of module test for steel story

just read through storylines :smile:
Original post by jam277
I wanna try and get one for chemistry lol because it's supposed to be my hardest subject but i find it easyish, it's just the exam, i didn't prepare properly. Though I'm ready for this I think. The next module is synoptic and you don't have much new stuff to learn so maybe it just might happen if it goes well on wednesday.


Ah, well good luck! Let's hope that we both don't make silly mistakes tomorrow. :smile:
Reply 112
Avatar for Legit
Legit
8
Just did June 2010
74/90 WHOOP!
Beyond A* :biggrin:
Reply 113
Avatar for Rei5
Rei5
ok could anyone ost a break down of the electrochemical cell!?
absolutely screws me in the papers... like i know everything else other then this confidently... so basically... HELP
Reply 114
Avatar for AGM
AGM
10
Just think in acid conditions;

Your base end is going to receive a proton so it's 2 amino acids, but with NH3+ groups instead of NH2.

In alkaline conditions;

Your acid end is going to donate protons so it's 2 amino acids, but with COO- groups instead of COOH
is it normal to feel kinda confident, but at the same time extremely worried? Ha!
Reply 116
Avatar for AGM
AGM
10
Just to summarise topics... is there anything more to learn than:

Steel Story:
BOS Process
D Block elements/Transition metals
Complexes
Electrode Potentials
Colour

Thread of Life:
Concentration vs. Rate
Optical Isomerism
Amino Acids
Enzymes/ enzymes and rate

Materials Revolution:
Amines and Amides
Polymers and their properties and what effects their properties
Recycling plastics and the atom economy bullcrap.

What's in a medicine?:
Carboxylic acids and deriatives
The OH groups in phenols/carboxylic acids/alcohols - how you tell the difference/how structure affects their acidity
Esters
Different types of reactions
Aldehydes and ketones and alcohol oxidation
Acid-Base reactions and zwitterions and all dat stuffums
Mass Spectrometry - Hi-res and lo-res

Practicals:
Titration
Recrystallisation
Heat under reflux - why?
TLC
Standard Electrode Potential ( Hydrogen vs. something else)

If this was a checklist, can anyone see anything that is missing?
yeah you missed colorimetry off the practicals list?
Original post by SarahPops
Thank you so much!!!! My mind is put at ease!!!


It's called a zwitterion and can exist with the ammonum or the cooh?
Reply 119
Avatar for Rei5
Rei5
electrochemical cell anyone?

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