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OCR Chemistry AS ATOMS BONDS GROUPS :: POST EXAM DISCUSSION!! How did it go for you?

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Reply 80

TwirlGirl

belgianchoco

What about the question about what color you can see

I put violet and then no change/clear

violet
orange

Reply 81

juman786

Freerider101

Yeah I'm fairly gutted now. And I checked the textbook. It does say H+ and HSO4 - ions! So I've lost a mark there too!

i dont understand, sulfuric acid is a strong acid there it should fully dissociate,

Reply 82

googoo09

ok well new question about that cheeky h2so4.... did you guys put anything on the left hand side of the --->
like did you put h2so4 + aq... or just on its own?

Reply 83

SophiaKeuning

I dunno.... I didn't have to resit. :sexface:

... because a crappy little C is good enough for me. :teehee:

Reply 84

Freerider101

belgianchoco

What about the question about what color you can see

I put violet and then no change/clear

Order was Purple, Orange (already filled in), Orange

Reply 85

juman786

googoo09

ok well new question about that cheeky h2so4.... did you guys put anything on the left hand side of the --->
like did you put h2so4 + aq... or just on its own?

didnt write (aq) , because its only one mark i assumed they werent looking for state symbols,

Beside the question did say the ions are in solution.

Reply 86

TwirlGirl

juman786

i dont understand, sulfuric acid is a strong acid there it should fully dissociate,

Yes i know.

But it has 2 dissociations, so it's a fairly ambiguous question

First dissociation: H+ HSO4-
Second dissociation: 2H+ SO42-

I think we got it wrong though, because in the question i vaguely remember it saying two ions and our answer has three. Annoying!

Reply 87

juman786

Freerider101

Order was Purple, Orange (already filled in), Orange

im sure it Cl2 with 2I- (expt:1) was brown =S

Reply 88

juman786

TwirlGirl

grrrrrrrrrrrrrrrrrrrr!

Reply 89

juman786

the 2nd question about sub-atomic particles, was that about the no. of electrons, protons and neutrons?

Reply 90

TwirlGirl

juman786

im sure it Cl2 with 2I- (expt:1) was brown =S

brown/orange/yellow are usually all allowed in the MS

Reply 91

Mainguy

juman786

NO , u answer is correct

think about it

H2SO4 , there are two protons therefore 2+ charge from both protons therefore SO4 MUST be 2- in order to balance the charge.

im 100% sure about this, i do A2 Chem

Well on page 22 about 2/3 down it says HSO4-. Only one H+ is released.

Reply 92

juman786

Mainguy

Well on page 22 about 2/3 down it says HSO4-. Only one H+ is released.

kill me...kill me now

Reply 93

Keorl

Any rough ideas how many marks out of 60 would be an A??

Reply 94

juman786

Keorl

Any rough ideas how many marks out of 60 would be an A??

i would say 50 and above

Reply 95

Keorl

juman786

i would say 72 and above

thats 48 out of 60....damn

Reply 96

juman786

rough estimate thoug based upon the grade threshold of jan 09

Reply 97

BeckyBaby

Freerider101

I thought the atomic radii question was kind of hard. Like 4 marks. So I'm assuming you get one for saying they decrease across a period. One for saying because the nuclear charge was increasing. Maybe another for saying that shielding isn't a factor because all the electrons were in the same shell. But I'm not sure where a fourth mark would come from?!

Wasn't it one of the WRC questions? So you'd get a mark for the way you wrote the answer and spelling something easy like "electrons" or something, they've done that in the past.

Reply 98

BeckyBaby

Arrgghh okay. That ionisation question, i think i may have got the energies write, but i wrote down the literal energy figure (ie. 18 723 or whatever they were) :frown:

Do you think they'll put that as wrong? Because i didnt answer in the right format?!

Reply 99

juman786

Mainguy

Well on page 22 about 2/3 down it says HSO4-. Only one H+ is released.

you know what i think both would be correct

H+ and HS04-

or

H+ SO42-

because sulfuric acid dissociates twice and the question was not specific on how much it dissociated