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Edexcel Official Chemistry Paper1:Core Inorganic and Physical Chemistry - 27th of May Watch

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    (Original post by JAFF2400)
    Can anyone help me with this question please?
    (topix 3 redox)

    7. Write balanced equations for these redox reactions. State which element is oxidized and which is reduced in each example.
    a) Fe and Br2 to give FeBr3

    Overall equation: ………………….

    Element oxidized: …………………

    Element reduced: ………………

    I know that Fe has oxidized because its oxidation state went from 0 to 3+

    and that Br has been reduced as its oxidation state went from 0 to -1 (single atom)

    And for the half equations i got: Fe ---> Fe^3+ + 3e^- & 3e^- + 3Br ----> Br3^-

    same number of electrons in both half equations so it should make

    Fe + 3Br ----> Fe^3+ + Br3^-

    but the mark scheme says:2Fe(s) + 3Br2 (l) ----> 2FeBr3(s)

    Can someone explain what i did wrong? is it because i changed the Br2 into Br?
    Yes that was the mistake because bromine MOLECULES(Br2) are reduced, not bromine atoms.
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    can anyone help me hava a last minute revision..tommorrows the exam and im really nervous...
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    (Original post by helloitsme7)
    Hello everyone!Could anyone please explain me why the answer is B ?- A sample of swimming pool water contains 0.482 ppm of chlorine. This is equal to a percentage of:A. 0.000482B. 0.0000482C. 0.00000482D. 0.000000482
    0.482/1000000 *100 = B , dont think u need to know this for new spec

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    (Original post by EUSHA)
    Yes that was the mistake because bromine MOLECULES(Br2) are reduced, not bromine atoms.
    Thanks for your help!
    I have one question tho say an atom doesn't reduce or oxidize it stays the same. Do i have to make a half equations for it? example F2 + H2O ---> HF + O2 I know that the oxygen has oxidized and the F2 has reduced but hydrogen stays the same. do i just make half equations on F2 and O2 and ignore H2 but include it in the overall equation?
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    Could someone explain what dative covalent bonding is? Thank you. 😊


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    (Original post by SquishyFishy)
    Could someone explain what dative covalent bonding is? Thank you. 😊


    Posted from TSR Mobile
    Dative bonding forms when the shared pair of electrons in the covalent bond comes from one of the bonding atoms.
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    (Original post by SquishyFishy)
    Could someone explain what dative covalent bonding is? Thank you. 😊

    Posted from TSR Mobile
    This is a covalent bond in which both of the electrons come from the same atom. It is represented by an arrow ----> from the atom providing the pair of electrons going towards the atom without a full octet (empty orbital)
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    (Original post by JAFF2400)
    Thanks for your help!
    I have one question tho say an atom doesn't reduce or oxidize it stays the same. Do i have to make a half equations for it? example F2 + H2O ---> HF + O2 I know that the oxygen has oxidized and the F2 has reduced but hydrogen stays the same. do i just make half equations on F2 and O2 and ignore H2 but include it in the overall equation?
    No. hydrogen stays the same so they are spectator ions. you dont include them in the overall ionic equation. the overall ionic equation would be: 2o^2- +2f2--->4f^- +o2
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    (Original post by EUSHA)
    No. hydrogen stays the same so they are spectator ions. you dont include them in the overall ionic equation. the overall ionic equation would be: 2o^2- +2f2--->4f^- +o2
    Doing an all nighter?
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    (Original post by sushifish)
    Doing an all nighter?
    Actually its not that man. I'm from Bangladesh and here it's 7 in the morning. Exam starts form 10:30 so im up for some last minute revision.
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    (Original post by EUSHA)
    Actually its not that man. I'm from Bangladesh and here it's 7 in the morning. Exam starts form 10:30 so im up for some last minute revision.
    Oh Okay, So are we doing the same paper? Im in the UK
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    (Original post by sushifish)
    Oh Okay, So are we doing the same paper? Im in the UK
    maybe. im doin IAL edexcel
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    Is it no Hess's cycle in the new spec ?
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    (Original post by kpm123)
    Is it no Hess's cycle in the new spec ?
    hess cycle definitely WON'T be on today's paper, but may be in the Paper 2 on the 10th of June.
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    (Original post by richpanda)
    hess cycle definitely WON'T be on today's paper, but may be in the Paper 2 on the 10th of June.
    but it was
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    Yo whats the enthalpy change of the alkane with c h2 o2,

    And whats the mutiple choice answer of the reforming
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    (Original post by Hamadtype-)
    Yo whats the enthalpy change of the alkane with c h2 o2,

    And whats the mutiple choice answer of the reforming
    i don remember
    the reforming one i gave D
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    Can anyone tell me what they got for the undiluted concentration of HNO3 in gmol-1?
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    How did people find it? I remember i got 10 g/dm^3 for the concentration of the undissolved HNO3 but i think this was wrong
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    (Original post by EUSHA)
    but it was
    You're on the wrong forum, you must have done a paper different to Edexcel AS Chemistry 8C01/01
 
 
 
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