Chemistry unit 6 June 2016

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    For some reason I can't work out the initial rate

    So for the order of potassium manganate I know you'll have to look at A and B. So the volume will be halved

    For the order of Glucose, you look at A and C, so the volume will be doubled.

    And for the order of Sulfuric acid, you look at C and D, so the vol will be halved.

    Now how do I work out the initial rate cos they're quite small and hard to compare??

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    (Original post by Adorable98)

    Why is this the answer:
    It contains a phenol group/has OH attachedto benzene ring.

    I wrote x contains a Cl-
    The test for phenol is that it forms aN INSOLUBLE white ppt. with bromine solution!
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    (Original post by samb1234)
    We know that the compound contains a benzene ring. If we try and react benzene with bromine water, we will get no reaction as the electron density of the benzene ring is not high enough to form the required Br+ electrophile, so if you wanted to brominate benzene you would need to generate Br+ in another way. In comparison, in phenol the lone pairs of the oxygen are partially delocalised into the ring system giving it a much higher electron density, such that it can polarise the Br-Br bond sufficiently for an electrophilic substitution reaction to occur. After one bromine has added, it is possible for another 2 to substitute onto the ring, and for reasons you don't need to know they will always be in position 2,4,6 so you get 2,4,6-tribromophenol (or a variant of this) which is a white precipitate
    Thank you soo much!!
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    (Original post by Aimen.)
    The test for phenol is that it forms aN INSOLUBLE white ppt. with bromine solution!
    Thank you!!
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    (Original post by PlayerBB)

    What does everyone think about Q.3 January 2016, was it SO HORRIBLE or is it just me ?
    The whole paper seems like an anomaly tbh
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    (Original post by Adorable98)
    For some reason I can't work out the initial rate

    So for the order of potassium manganate I know you'll have to look at A and B. So the volume will be halved

    For the order of Glucose, you look at A and C, so the volume will be doubled.

    And for the order of Sulfuric acid, you look at C and D, so the vol will be halved.

    Now how do I work out the initial rate cos they're quite small and hard to compare??

    Why do you need to find the initial rate when they just ask for rate equation?? which is Rate=k[H+][Mno4-] as reaction is zero order w.r.t to glucose
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    (Original post by Mehodax)
    The whole paper seems like an anomaly tbh
    I'd rather call it TOXIC AND HAZARDOUS!
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    (Original post by Aimen.)
    Why do you need to find the initial rate when they just ask for rate equation?? which is Rate=k[H+][Mno4-] as reaction is zero order w.r.t to glucose
    So that I could find the order? Why are you comparing to glucose?
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    (Original post by Mehodax)
    The whole paper seems like an anomaly tbh
    Lol, you got that right, it was so weird!!
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    (Original post by aimen.)
    i'd rather call it toxic and hazardous!
    lol, it is!!!
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    Is the examiner report wrong?
    It says that the voltmeter is incorrect but they've included it in mark scheme



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    (Original post by Adorable98)
    Is the examiner report wrong?
    It says that the voltmeter is incorrect but they've included it in mark scheme



    Which paper is this?

    I guess just 'voltmeter' would be penalised.
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    (Original post by Mehodax)
    Which paper is this?

    I guess just 'voltmeter' would be penalised.
    June 2014 IAL
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    In steam distillation, where would the crushed lavender flower be,

    In the first flask with the boiling distilled water or the second one?

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    (Original post by PlayerBB)
    Depends, what do you exactly mean by basic one ?
    Paper chromatography I meant to say.(Sorry I am tensed like anything for the paper so I'm forgetting stuff)
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    (Original post by Adorable98)
    Is the examiner report wrong?
    It says that the voltmeter is incorrect but they've included it in mark scheme



    No it is correct. Using a voltmeter is not wrong, using voltmeter W is wrong as it is low resistance, whereas we want a voltmeter with infinitely high resistance (since if you do physics from product/sum rule the resistance of the 2 things in parallel will tend to the resistance of the thing the voltmeter is across, meaning that it doesn't effect the voltage across the component (as potential divider)). If you don't do physics ignore all that and just learn that voltmeters should have high or ideally infinite resistance
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    (Original post by Adorable98)
    Thank you!!!!
    Most welcome! All the best for tomorrow.
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    (Original post by samb1234)
    No it is correct. Using a voltmeter is not wrong, using voltmeter W is wrong as it is low resistance, whereas we want a voltmeter with infinitely high resistance (since if you do physics from product/sum rule the resistance of the 2 things in parallel will tend to the resistance of the thing the voltmeter is across, meaning that it doesn't effect the voltage across the component (as potential divider)). If you don't do physics ignore all that and just learn that voltmeters should have high or ideally infinite resistance
    I see!! Thank you once again!!
    (Original post by sabahshahed294)
    Most welcome! All the best for tomorrow.
    You too!!
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    (Original post by PlayerBB)
    Thank you guys so much, I have been stuck on this for ages and it didn't cross in my mind that it would be related to full 3d sub-shell

    What does everyone think about Q.3 January 2016, was it SO HORRIBLE or is it just me ?
    Whenever you see 'white' and a transition metal in the same sentence, this will always be the way to go about it as all transition metal compounds are coloured unless they have full d orbitals.
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    (Original post by Mehodax)
    In steam distillation, where would the crushed lavender flower be,

    In the first flask with the boiling distilled water or the second one?

    Name:  13214415_1268655789829675_137644811_o.jpg
Views: 69
Size:  89.5 KB
    Does know have any idea about this one?
 
 
 
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