iGCSE 2012 Chemistry Discussion

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Which part?

All of it was okay except the one where it said suggest the relative melting point of this mixture to the other or something, that really confused me :frown:

Reply 521

yiannis1995

Can someone upload the paper please?

Reply 522

taylorswiftx

just wondered has anyone uploaded an unofficial mark scheme for the chemistry paper 1c (double award science IGCSE) , like they did for biology? Just asking because don't want to flick through 27 pages :smile:

Reply 523

Debate

For the negative ion which can't be detected through precipitation question, would O 2- count as an answer?

Reply 524

member963009

Original post by taylorswiftx

Original post by yiannis1995

Can someone upload the paper please?

We need the paper, ask your centres people! I already asked mine

Reply 525

lily-anne01

Original post by SupremeNunchucks

Dammn i got 22.3 :frown:

more marks lost there..

Im pretty sure the answer was 2.4, because there were two moles rather than one mole.. :confused:

Reply 526

lily-anne01

Did you guys get: Lithium, Iron (II) and Iodine for the colours of ppt and flame test?! :smile:

Reply 527

Rss777

Original post by lily-anne01

Did you guys get: Lithium, Iron (II) and Iodine for the colours of ppt and flame test?! :smile:

the first one was potassium not lithium because the flame colour was lilac

Reply 528

lily-anne01

Original post by Rss777

the first one was potassium not lithium because the flame colour was lilac

yes you're right! i put that sorry mis-typed!

Reply 529

antonini

what did u guys get for the colour change question?

I said the salt solution went from orange to colourless because bromine in aq is orange but then chlorine displaces it and forms nacl which is colourless.

helppppp :smile:

Reply 530

member963009

Original post by antonini

No Br is displaced so at the end so br is dissolved so it goes from colourless to bromine. well i think anyway

Reply 531

MerveK

Original post by sahajkaur

All of it was okay except the one where it said suggest the relative melting point of this mixture to the other or something, that really confused me :frown:

I agree you :/

This was posted from The Student Room's iPhone/iPad App

Reply 532

lily-anne01

for the question when you had to name particle a? what did you put?

Reply 533

Sub150

Original post by sahajkaur

No Br is displaced so at the end so br is dissolved so it goes from colourless to bromine. well i think anyway

I dont think so... NaBr is made into NaCl right? So wouldnt that mean that Bromine gas escapes? so the solution is colourless, but the gas let out is brown? Confused me that one :s-smilie:

Reply 534

AM.95

Original post by lily-anne01

for the question when you had to name particle a? what did you put?

I put that it was a Silicon atom due to the two single bonds between the silcon and the oxygen, although apparently thats wrong :mad:

It was oxygen. I got that whole page wrong as i put ionic as i thought silicon was a metal however the bonding is giant covalent :frown:

. 8 marks lost there, i need a good performance in 2C to get an A*. I reckon it will be much easier

(edited 11 years ago)

Reply 535

Sub150

Oh yeah, for the first part (I think) of that question, where it says what happens when CaSiO3 is formed by the reaction between CaO and SiO2, is it neutralisation or the breaking of Ionic bonds to make covalent bonds?? I've asked like 5 people, and none of them know for sure...

Reply 536

AM.95

Original post by Sub150

Not sure either, majority of people i have asked say something along the lines of neutralisation but they weren't absolutely sure. :s-smilie:

Reply 537

Debate

Was neutralisation, I thought it was ionic so said it was Si 4+ ion.... ;P the answer was silicon atom

Reply 538

Sub150

Mm, I wasnt sure because there are no Hydroxonium ions involved... So there is an acidic or basic compound (the question said that it was pure SiO2 which is not acidic)
Is CaO basic?? because it doesnt have a pH if it isnt in soln does it??