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

Mainguy
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#61
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#61
I also got 98.4% for the calculation...I was pretty sure about that. I know I lost the mark for writing S04 not HS04.

What did everyone say for the trend observed upon heating the carbonates down the group? I put something like it got more difficult and it'd take longer....Think that's wrong though.

Overall seemed like an average difficulty paper imo, no harder/easier than others.
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juman786
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#62
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what did ppl write for:

"what is the total number of electrons found in the p orbitals for chlorine"

I wrote 11 because there is 2p6 and 3p5....3+5=11
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juman786
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#63
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(Original post by Mainguy)
I also got 98.4% for the calculation...I was pretty sure about that. I know I lost the mark for writing S04 not HS04.

What did everyone say for the trend observed upon heating the carbonates down the group? I put something like it got more difficult and it'd take longer....Think that's wrong though.

Overall seemed like an average difficulty paper imo, no harder/easier than others.
i read that part in the examiners book, the answer is

"the ease of thermal decomposition decreases as you go down the group"
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Billton
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#64
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#64
I thought it went Ok, some of the 4 markers might be a bit dodgy though because the mark schemes are so specific, and I didn't revise much because I was only after a few more UMS marks
Good luck everyone
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Freerider101
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#65
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#65
(Original post by FantAbyLus)
I lost marks for sayin as u go down the groups the carbonate becomes more reactive and for sayin it was SO4(2-) in stead of sayin HSO4(-) and funny thing is, i wrote it but i crossed out the H cos i thot it was wrong
The wierd calculation one, did anyone get 98.4% ?
Ohh and for the polar molecule i said F was more electronegative than N and that the shape is not symmertrical so the dipoles dont cancel out? Not sure about dat :/
I thought it was one SO4 2- ions and 2 H+ ions
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googoo09
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#66
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#66
You know the question on the first page involving avigadro (however its spelt), and if it even involves that....
it was like 2kg or something, so did you all do
2000
over
118 (or whatever the mass is of whatever element)

then that multiplied by avigadros? something to the power of 25?

and yea i got some late 90s percent for that washing powder one but what confused me was if it was the say, 98%, you put down or the 2ish?
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Mainguy
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#67
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(Original post by Freerider101)
I thought it was one SO4 2- ions and 2 H+ ions
Nope in the book it says:

H+ ion and a HSO4- ion. I was so close to doing that as well, damnit.
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Freerider101
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#68
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#68
(Original post by BeckyBaby)
Yeah I got 120 degrees Trigonal Planar. I think you have to state the obvious initially; that it has 3 bonded pairs and no lone pairs, then go on to say how three bonded pairs cause equal repulsion around the B atom.

I didn't find it as hard as I feared, considering resits are apparently harder to get higher marks on. I completely failed the % question, but the ionic/covalent/atomic radii questions I thought were pretty fair

I got an E first time round so hopefully it won't be too hard beating that now

Now just mod 2 to go
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?!
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googoo09
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#69
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#69
oh also
H2SO4 ---------> H+ + HSO4-
but... did you put H2SO4 + aq... or did you not? i got a bit confused there and didnt put + aq in
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juman786
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#70
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(Original post by googoo09)
You know the question on the first page involving avigadro (however its spelt), and if it even involves that....
it was like 2kg or something, so did you all do
2000
over
118 (or whatever the mass is of whatever element)

then that multiplied by avigadros? something to the power of 25?

and yea i got some late 90s percent for that washing powder one but what confused me was if it was the say, 98%, you put down or the 2ish?

Yes for the tin atom Q, u work out the moles (they gave u the Mass of tin) then times the moles by the avargadro constant.

As for the two ions present in a H2S04 solution, the answer was H+ and S042-
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Freerider101
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#71
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(Original post by Mainguy)
Nope in the book it says:

H+ ion and a HSO4- ion. I was so close to doing that as well, damnit.
Where does it say that in the book? Is this the heinmann textbook. And yeah I'm gutted I put 2x H+ and SO4 2-
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googoo09
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#72
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#72
(Original post by 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?!

from past papers id say the marks would be for:
radii decreases accross the period (1) because...
same shell because same period, so the same shielding (1) which then isnt a factor
nuclear charge increases accross (1)
a greater attraction to the nucleus of the outer electrons bringing them in(1)

just guessing
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Freerider101
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#73
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(Original post by googoo09)
You know the question on the first page involving avigadro (however its spelt), and if it even involves that....
it was like 2kg or something, so did you all do
2000
over
118 (or whatever the mass is of whatever element)

then that multiplied by avigadros? something to the power of 25?

and yea i got some late 90s percent for that washing powder one but what confused me was if it was the say, 98%, you put down or the 2ish?
Yeah i got 10 to the power of 25 too
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juman786
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#74
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#74
(Original post by Freerider101)
Where does it say that in the book? Is this the heinmann textbook. And yeah I'm gutted I put 2x H+ and SO4 2-
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
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googoo09
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#75
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#75
(Original post by juman786)
Yes for the tin atom Q, u work out the moles (they gave u the Mass of tin) then times the moles by the avargadro constant.

As for the two ions present in a H2S04 solution, the answer was H+ and S042-
no... im sure it is h+ and hso4-
page 22 of the ocr heinnmen book
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juman786
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#76
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(Original post by googoo09)
from past papers id say the marks would be for:
radii decreases accross the period (1) because...
same shell because same period, so the same shielding (1) which then isnt a factor
nuclear charge increases accross (1)
a greater attraction to the nucleus of the outer electrons bringing them in(1)

just guessing
yep like u , iv seen all the past papers and that was the mark sheme for that Q
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Freerider101
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#77
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(Original post by juman786)
what did ppl write for:

"what is the total number of electrons found in the p orbitals for chlorine"

I wrote 11 because there is 2p6 and 3p5....3+5=11
Dam I put 5 thought it was just on about the particular shell...
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TwirlGirl
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#78
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(Original post by juman786)
Yes for the tin atom Q, u work out the moles (they gave u the Mass of tin) then times the moles by the avargadro constant.

As for the two ions present in a H2S04 solution, the answer was H+ and S042-

I wrote that but everyones saying HSO4- and H+ ...
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TwirlGirl
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#79
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#79
(Original post by Freerider101)
Dam I put 5 thought it was just on about the particular shell...

Me too! Didnt read the question just jumped straight in :erm:
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belgianchoco
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#80
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#80
What about the question about what color you can see

I put violet and then no change/clear
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