Edexcel chemistry 1 Watch

frankie einstein
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#581
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#581
January 2010 A thresholds;
Unit 1: 48/80
Unit 2: 51/80

Good luck to everyone
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obviouslystudying
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#582
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#582
(Original post by FallenPetal)
This was lumped in with having to also revise for this exam and the upcoming c5 ^^ Mechanics in 40hrs 15min. Ugh.
you doing AS & A2?
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abercrombie_bex
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(Original post by obviouslystudying)
I thought the question said how many peaks would a sample of bromine have. i got 55 peaks like 79Br+, 81Br+, (79Br-79Br)+, (79Br-81Br)+, (81Br-81Br)+

Correct me if I'm wrong..this may either sound SOOO stupid or be quite good.
I said there would be 2 peaks since it clearly said in the question STABLE isotopes. So I figured, if they're stable, they wouldnt fragment in the mass spectrometer and therefore you'd only have 2 peaks.
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woozeybear
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#584
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#584
(Original post by FallenPetal)
I got Cs at AS and a D at A2 (and I worked loads harder for that one :mad: ). On the c1 past papers I got 82%, 84% and 88% so hopefully I can get an A in this retake + I hated the practicals. My teacher described me as having "an extraordinary ability to make stupid mistakes" :rolleyes:

I know what you mean *coughs*mechanics*coughs*. I like unit 5. The synthesis part meant that I had to learn all of the organic chemicals reactions again - which makes doing retakes much easier. Did you do the specimen paper?
That's good I got 80% and 79% for the Chem 1 past papers but depends really.. And aww hopefully you won't maybe you do what I do which is look at the question and assume you know what they're gonna ask (did that in gcse maths I worked out the side of a triangle when they wanted the area :facepalm:) and I learnt the reactions well the ones on page 118 of the cgp revision guide I was like ooooh that's how that happens! I haven't done the unit 5 specimen paper yet I think were doing it Tuesday but i don't want to do it with no revision the bit of unit 4 I hated was NMR and Infra red and tadaaa 14mark question!
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obviouslystudying
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#585
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(Original post by abercrombie_bex)
Correct me if I'm wrong..this may either sound SOOO stupid or be quite good.
I said there would be 2 peaks since it clearly said in the question STABLE isotopes. So I figured, if they're stable, they wouldnt fragment in the mass spectrometer and therefore you'd only have 2 peaks.
Maybe you're right, i was going so fast that probably I didnt read the question correctly (has happened this june, phy 3b, missed part of the q)
but I think stable isotopes means naturally occuring isotopes. I mean a 12C-12C bond may also break, but its the more stable isotope of C.

Anyway, even if it didnt fragment or the question asked for the molecular peaks, it would be 3 peaks, not 2 peaks.
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abercrombie_bex
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(Original post by obviouslystudying)
Maybe you're right, i was going so fast that probably I didnt read the question correctly (has happened this june, phy 3b, missed part of the q)
but I think stable isotopes means naturally occuring isotopes. I mean a 12C-12C bond may also break, but its the more stable isotope of C.

Anyway, even if it didnt fragment or the question asked for the molecular peaks, it would be 3 peaks, not 2 peaks.
Why would it be 3 peaks?
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obviouslystudying
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#587
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#587
(Original post by Soppe)
I think 1 week solid you could finish the WHOLE chem topics... That's AS n A2
Ya, only 1 problem with it. I've got about 9 days holiday and i need to finish 4 subjects AS (mostly unit 2s) & A2.
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FallenPetal
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#588
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(Original post by obviouslystudying)
you doing AS & A2?
I'm doing all of the chem exams this summer. yay. :/
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obviouslystudying
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#589
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#589
(Original post by frankie einstein)
January 2010 A thresholds;
Unit 1: 48/80
Unit 2: 51/80

Good luck to everyone
Thats good news. If only you could find the minimum marks which had to be attained to get 120/120 for results sheet...
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FallenPetal
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#590
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(Original post by woozeybear)
That's good I got 80% and 79% for the Chem 1 past papers but depends really.. And aww hopefully you won't maybe you do what I do which is look at the question and assume you know what they're gonna ask (did that in gcse maths I worked out the side of a triangle when they wanted the area :facepalm:) and I learnt the reactions well the ones on page 118 of the cgp revision guide I was like ooooh that's how that happens! I haven't done the unit 5 specimen paper yet I think were doing it Tuesday but i don't want to do it with no revision the bit of unit 4 I hated was NMR and Infra red and tadaaa 14mark question!
I think that, in terms of chemistry marks, that's a good A The girl who used to sit next to me in chem just spend the whole first term doodling on a bit of paper and she got the highest mark on that paper. bah.

I do that. Lots. Then I suppose I can't say what I wanted to say about it :P It was annoying, I dropped lots of marks making stupid errors I didn't do much for it, no time. I don't think I did that badly on it actually, so I'm quite happy (and apparently the grade boundries are really really low).

I ran out of time to do that one properly. Probably explains the D.
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shadow12345
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#591
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#591
Yh troll ur In the same boat as me... I got 11 more
exams.... As n a2

m1 on Monday, phys on Thursday ... Whoa I got loads to do
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obviouslystudying
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#592
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#592
(Original post by abercrombie_bex)
Why would it be 3 peaks?
because the molecules will have two atoms of 79-Br or 81-Br or one atom from each isotope.
peaks would be from:
(79Br-79Br)+, (79Br-81Br)+, (81Br-81Br)+
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amani-puresapphire
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#593
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(Original post by FallenPetal)
Idk, I wasn't even acutely aware I knew how acid rain was formed. I just remember vaguely doing it at GCSE. It's probs in the revision guide, but I skimmed over all the environment stuff. It was a par-GCSE question anyways.

If you weren't sure you should have just put it's symbol down :P
haha well urm that didn't cross my mind? :tongue:
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abercrombie_bex
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(Original post by obviouslystudying)
because the molecules will have two atoms of 79-Br or 81-Br or one atom from each isotope.
peaks would be from:
(79Br-79Br)+, (79Br-81Br)+, (81Br-81Br)+
Was this in the CGP revision guide or facer book? Because I've honestly never known how to work that out and I dont really get it! Though if it said stable isotopes, then why would there be more than 2 peaks??
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FallenPetal
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#595
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(Original post by abercrombie_bex)
Why would it be 3 peaks?
Because what's happening, after the Br2 has been vapourized, electrons are fired at the molecules - only removing an electron, not breaking the molecule up. This forms Br2+ ions, which is what the question was referring to when it wanted to know how many peaks formed.

The Br molecule is made up of two Br molecules, since both of the isotopes still have the same number of electrons you can assume they both act chemically identically, so it will either be
a) A possible two made up of one isotope.
b) A possible one made up of one of each isotope.

We can detect this since each of the three have a different RMM and would hit the detector in different magnetic fields.
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woozeybear
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#596
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(Original post by FallenPetal)
I think that, in terms of chemistry marks, that's a good A The girl who used to sit next to me in chem just spend the whole first term doodling on a bit of paper and she got the highest mark on that paper. bah.

I do that. Lots. Then I suppose I can't say what I wanted to say about it :P It was annoying, I dropped lots of marks making stupid errors I didn't do much for it, no time. I don't think I did that badly on it actually, so I'm quite happy (and apparently the grade boundries are really really low).

I ran out of time to do that one properly. Probably explains the D.
For the specimen or for the paper we just took? Unit 2 and 1 in June were on the same day so I didn't know how to revise or where to start, so ended up getting a D in unit 2 hopefully resits will work out :s
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abercrombie_bex
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#597
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(Original post by FallenPetal)
Because what's happening, after the Br2 has been vapourized, electrons are fired at the molecules - only removing an electron, not breaking the molecule up. This forms Br2+ ions, which is what the question was referring to when it wanted to know how many peaks formed.

The Br molecule is made up of two Br molecules, since both of the isotopes still have the same number of electrons you can assume they both act chemically identically, so it will either be
a) A possible two made up of one isotope.
b) A possible one made up of one of each isotope.


We can detect this since each of the three have a different RMM and would hit the detector in different magnetic fields.
Ohhhh!! Thank you soo much!! You've explained it sooo well. I'm glad even though my answer was wrong, that it was logical. Lol. Now I get it!! Yayy thank you!!
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obviouslystudying
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#598
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(Original post by abercrombie_bex)
Was this in the CGP revision guide or facer book? Because I've honestly never known how to work that out and I dont really get it! Though if it said stable isotopes, then why would there be more than 2 peaks??
not sure, since the textbook i had wasnt for this syllabus, so i learned from another book of my teacher.
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obviouslystudying
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#599
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#599
(Original post by FallenPetal)
Because what's happening
so, why not 5 peaks?
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CityOfMyHeart
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#600
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#600
(Original post by obviouslystudying)
so, why not 5 peaks?
I put 5 peaks.

One at 79, one at 81.
And then three for the molecule combination because Bromine's diatomic (so peaks at 79+79, 79+81 and 81+81).
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