The Student Room Group

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Reply 1
Easy if you had revised the stuff, especially the HCl and Carbon Dioxide question. The mass spectrometer question took me a lot longer than it should have, and I think I may have dropped a mark on it. How did you find it?
Reply 2
very hard
what were the axis and values and heights of Cl
Reply 3
Relative abundance on the Y axis, m/z on the x-axis. The 37 peak should have been 1/3 the size of the 35 peak, with two smaller peaks at 17.5 and 18.5. I think it was a harder paper than recent ones, so I suspect the grade boundaries may be lower than last years.
Reply 4
did they definately have to be shorter?
Reply 5
I would say so, 2+ ions are less likely than + ions
Reply 6
what about the moles questions
the one to work out the mass of hydrated sodium carbonate?
Reply 7
Yes, they have to be shorter. Only the most energetic electrons have the ability to remove the second electron. 2BH I screwed up, it was very difficult in my opinion, and that's the same response I got from my class mates. Any rough guestimates on grade boundries?
Reply 8
37.1% of the hydrated sodium carbonate was sodium carbonate by mass is what I got, can't remember what the questions were! Anyone remember?
Reply 9
isnt it about marks rather than grade boundaries?
Reply 10
Kinda, but, I wish to know the rough grade bounries... I mean based on the difficulty of the paper, how many marks do you think we could drop and still get an A?
bout 15 im guessing
Reply 12
That's quite alot 2bh, it's normaly around the 7-9 mark!
yh sorry, that would be for biology, which is much harder
i would probably say about 10
I'm guessing about 47 for a grade A, 42 for a B or maybe a bit lower
what did you get for the equation, product and observation in the first part of the last section A question?
first one, bubbles of a colourless gas, carbon dioxide, 2H+ + (CO3) 2- ---> H20 + CO2
second one,
white precipitate, barium sulphate, Ba2+ +(SO4)2- -----> BaSO4
ah we never learnt that and it was never in our textbooks
o well, i knew it from science last year (but i still lost a mark for the wrong equation)

i know everyone else in my college would get that wrong though
yh second one was pretty easy

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