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    Did we have to state what the actual bond angle was? Or just state whether it was greater or smaller?
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    Just use the graph, from best fit

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    (Original post by f.loco)
    Q1:
    Mass of e: v.small
    The others are basic

    Ionisation
    Acceleration
    Drift region

    Mass spec, same Ek given to each particle heavier reach later than lighter which is detected by detector and form mass spec graph


    Left gaps so it fits the same patterns

    Beta decay was Se + 2e

    Vol of gas: 277.2/8

    Ar of Ge: 72.7

    Ion in end: SiO3^2-

    Bonding is ionic

    Cloudy as co2 forms precipitate

    NO2 as high temp and pressyre by engine creates right conditions for O2 and N2 to form bonds

    Reforming
    Hydrogen


    Purpose of catalyst to speed up reaction

    2 variables: same mass of metals
    Sams heating time

    -196kJmol^-1

    Bond angle: 109° but actual 104° as corners squeeze the electron clouds.

    Emision spec: descrete E level, e- absorb photon. Excited to higher shell. When return to geound state release photon of characteristic frequency eqaual to E/h. Diff spec for diff elements as diff electron arrangement

    Theres some answers i put down



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    How did you work out the volume one?
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    I got 1.7, knowing my luck it'll be 2.0 +/- 0.2


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    (Original post by ZoeWoah)
    How did you work out the volume one?
    1. Worked out the no of moles for all the compounds using n=m/Mr

    Then used V=n x 70 for both gases

    Then added the 2 volumes up (185.3484.. + 72.849..) which gave me 277.8 something

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    (Original post by f.loco)
    1. Worked out the no of moles for all the compounds using n=m/Mr

    Then used V=n x 70 for both gases

    Then added the 2 volumes up (185.3484.. + 72.849..) which gave me 277.8 something

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    I did the mr of hydrogen peroxide -.-
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    For the mass spectrometer question, in the 2014 paper it wanted you to say KE=1/2mv^2 for 1 mark. It never asked for that in papers before 2014 so I wrote that just to be safe.
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    (Original post by DominoMatrix227)
    How did everyone do that half life question? I took 3 values (all different) and took an average to get 2.0x10something.
    Clever, I only did one half life haha
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    I think ill get about 52/54 or something
    Any gueses on grade boundaries?
    I think for an A it will be 50

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    (Original post by ZoeWoah)
    How did you work out the volume one?
    Mol[H2O2] = (Mass)/(Mr) = ~2.something
    Stoichiometric ratio = 2:3
    * 70dm^3 = 278
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    (Original post by ZoeWoah)
    I did the mr of hydrogen peroxide -.-
    U do that first then compare ratios

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    (Original post by Shunder10)
    Mol[H2O2] = (Mass)/(Mr) = ~2.something
    Stoichiometric ratio = 2:3
    * 70dm^3 = 278
    didnt do the ratio will i get a mark by finding out the mr of hydrogen peroxide and mutiplying by 70?
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    (Original post by Adam971)
    For the mass spectrometer question, in the 2014 paper it wanted you to say KE=1/2mv^2 for 1 mark. It never asked for that in papers before 2014 so I wrote that just to be safe.
    I wrote this after the point about accelerating to same Ek
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    How did people do the dot and cross diagram??
    Mine was like
    [Sr]2+ + [O]2-
    with six dots and two crosses around the oxygen...
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    (Original post by f.loco)
    1.8 for half life

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    I got 1.8 as well!
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    (Original post by ZoeWoah)
    didnt do the ratio will i get a mark by finding out the mr of hydrogen peroxide and mutiplying by 70?
    You may

    But youve found vol of H2O2 not the other gases

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    (Original post by Shunder10)
    How did people do the dot and cross diagram??
    Mine was like
    [Sr]2+ + [O]2-
    with six dots and two crosses around the oxygen...
    I did this, initially drew it as covalent but it clicked 1 min before the end of the exam, lucky I had enough time
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    Do you think the grade boundaries will be higher than last year???
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    (Original post by f.loco)
    I think ill get about 52/54 or something
    Any gueses on grade boundaries?
    I think for an A it will be 50

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    It was 45 for the june 2014 paper, and I'm sure that was easier
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    (Original post by Shunder10)
    How did people do the dot and cross diagram??
    Mine was like
    [Sr]2+ + [O]2-
    with six dots and two crosses around the oxygen...
    I didnt put a plus sign in between the two, do i lose a mark, apsrt from that i got the other bits right

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