Salters Chemistry of Materials!

Ramaya

In January they asked that horrible question on rust that I just hated.

I remember that well. Recall the whole equation for rusting!? That was a beast. It's worth remembering though.

All the best for tomorrow, whoever happens to be sitting it.

Reply 22

Synkronized

I just had three nervous breakdowns over electrode potentials lol. I purposely left the steel story till last to revise!

I have to get an A in chemistry.. and if i don't improve tomorrow on the exam, that means getting 95/120 on the synoptic next week. Do-able, yes, probable, NO :frown:

.

25 mark essay sounds incredibly nasty btw for the AQA exam :s

why won't any of this chemistry go in?! argh!

I have to get 80/90 tomorrow, cos then my mark from last years chem by design will get me an A :biggrin:

But, my mark for this paper alays sucks, even when i think i am confident with it!

Reply 23

OP

kohlstream

I dont, and i dont have a scanner, but it's sitting on my desk! Is there anything particular you wanted to know, or did you want the whole paper/

was there much on electrode potentials and electrochemical cells in the one in jan at all?

Reply 24

AmS

was there much on electrode potentials and electrochemical cells in the one in jan at all?

''complete and label the diagram below to show how you would set up an iron-copper cell in the lab' (3)

calculate Ecell for this iron-copper cell (1)

give an equation for the overall cell reaction in i

(the answer was Fe+Cu2+ ---------> Fe2+ + Cu etc)

''the first stage of rusting involvesd the oxidation fo iron to iron (II), use the electrode potentials given above to explain how the precence of copper causes rusting to become more severe' (3)

the addition of copper and other elements to mild steel modifies the structure of the rust layer. This enables Corten steel to aquire a protective coating. suggest one way in which the physical properties of rust have been modified (1)

Reply 25

roochis

kohlstream

''complete and label the diagram below to show how you would set up an iron-copper cell in the lab' (3)

calculate Ecell for this iron-copper cell (1)

give an equation for the overall cell reaction in i

(the answer was Fe+Cu2+ ---------> Fe2+ + Cu etc)

''the first stage of rusting involvesd the oxidation fo iron to iron (II), use the electrode potentials given above to explain how the precence of copper causes rusting to become more severe' (3)

the addition of copper and other elements to mild steel modifies the structure of the rust layer. This enables Corten steel to aquire a protective coating. suggest one way in which the physical properties of rust have been modified (1)

I liked that question (except for the last bit - i still dont' understand the answer even though i have the mark scheme!)

But yeah, I'm a physics person so i kind of get that kind of stuff.. but then DNA.. i can't understand that for the life of me :s-smilie:

Reply 26

OP

kohlstream

''complete and label the diagram below to show how you would set up an iron-copper cell in the lab' (3)

calculate Ecell for this iron-copper cell (1)

give an equation for the overall cell reaction in i

(the answer was Fe+Cu2+ ---------> Fe2+ + Cu etc)

''the first stage of rusting involvesd the oxidation fo iron to iron (II), use the electrode potentials given above to explain how the precence of copper causes rusting to become more severe' (3)

the addition of copper and other elements to mild steel modifies the structure of the rust layer. This enables Corten steel to aquire a protective coating. suggest one way in which the physical properties of rust have been modified (1)

cheers for that! now i remember the rusting question, that was awful!lol

Reply 27

CrazyChemist

The rust is no longer hydrated (it forms an impenetrable layer), so the water can't penetrate the rust to the iron below and continue rusting, thus rust is prevented.

Edit: the physical change is that the rust is no longer permeable to water, or that the rust isn't hydrated (i think that would be accepted...no markscheme tho.)

Reply 28

'' rust is no longer flaky/layer adheres (more strongly) to steel / impermeable AW''

I assume AW stands for alternate wording

Reply 29

I just worked out a moles question! (throws a mini party) it was a rather fiendish one too, involving mols=mass/molar mass AND conc=mols/volume!

Excuse the enthusiasm, these easy calculations have cost me nearly half the marks at a-level chem.

Now, just gotta learn the rest of the syllabus :frown:

Good luck everyone, I'm off to cram madly!

Reply 30

Synkronized

I just worked out a moles question! (throws a mini party) it was a rather fiendish one too, involving mols=mass/molar mass AND conc=mols/volume!

Excuse the enthusiasm, these easy calculations have cost me nearly half the marks at a-level chem.

Now, just gotta learn the rest of the syllabus :frown:

Good luck everyone, I'm off to cram madly!

heh, me too!

best of luck

is the exam at 1?

Reply 31

kohlstream

heh, me too!

best of luck

is the exam at 1?

1:30 for me I think, but yeah, its in the afternoon. I just remembered what all the rate-concentration and rate-time graphs looked like! im on a roll! (another party breaks out)

Reply 32

Synkronized

1:30 for me I think, but yeah, its in the afternoon. I just remembered what all the rate-concentration and rate-time graphs looked like! im on a roll! (another party breaks out)

oops i forgot about those

Crap on a stick

Reply 33

Are we related or something? I say 'crap on a stick' too!

I hope they don't ask us to name any acyl chlorides tomorrow... my brain freezes at the thought! (yeah, still here, revising with the net on because im stupid!)

Reply 34

green_eyes

1

so...i just did this exam! and i thought it was really bad! i had revised really hard but thought most of the questions were ambiguous and badly worded. i think most people here thought it was a very very hard exam..what about everyone else?

Reply 35

OP

i know wat u mean, the things i did revise didnt seem 2 help much!lol.............it jus seemed a really weird paper compared 2 the past papers there have been?

Reply 36

green_eyes

1

yes, there were no really 'stories' like there usually are, and it was hit and miss with the questions. the only one i liked was drawing the electrochemical cell.
i was seriously considering writing a note to the examnier to say i thought the questions were ambiguous, but didn't.
oh god i realy hope the next one is ok, bu it won't be!

Reply 37

OP

yep i loved the electrochemical cell drawing and the thin layer chromatography, glad i revised them at the last moment!!! the one on tuesdays gonna be a complete nightmare for me........ 2 hours of hardcore chemistry!-not good.

Reply 38