Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta
    Offline

    1
    ReputationRep:
    Why is 6 the most common coordination number for transition metals
    Offline

    0
    ReputationRep:
    AQA is possible please
    Offline

    19
    ReputationRep:
    (Original post by Shadowninja107)
    Why is 6 the most common coordination number for transition metals
    Because (in low spin complexes) you can get 18 electrons in low lying orbitals.
    Offline

    0
    ReputationRep:
    Hi,

    Need major help on redox please and free radical substitution, i don't understand it at all, how do you work it out?

    Thanks

    x
    Offline

    2
    ReputationRep:
    Can someone help me out please?

    When CrO4 2- reacts with H+ ions to form Cr2O7 2- what do you call that? Is it reduction?
    Offline

    2
    ReputationRep:
    (Original post by shiney101)
    Can someone help me out please?

    When CrO4 2- reacts with H+ ions to form Cr2O7 2- what do you call that? Is it reduction?
    Oxidation state of Cr in CrO4 2- is +6.
    Oxidation state of Cr in Cr2O7 2- is +6

    Therefore not a redox reaction
    Offline

    0
    ReputationRep:
    (Original post by SamuelN98)
    Do either of you have the answers to the questions from the practical book?
    i cant find them anywhere.
    They could be on Maths and Physics Tutor? I've never looked for them if I'm honest.. 🙊
    Offline

    17
    ReputationRep:
    (Original post by farihak97)
    Hi,

    Need major help on redox please and free radical substitution, i don't understand it at all, how do you work it out?

    Thanks

    x
    What do you need to know about it?

    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    (Original post by SamuelN98)
    Oxidation state of Cr in CrO4 2- is +6.
    Oxidation state of Cr in Cr2O7 2- is +6

    Therefore not a redox reaction
    So what would you call this reaction?
    Offline

    2
    ReputationRep:
    (Original post by shiney101)
    So what would you call this reaction?
    I don`t know exactly as its not on my syllabus, i was just making an educated guess. I think you would call it an equilibrium reaction.
    This may help.
    http://www.slideshare.net/pieferrer/...te-equilibrium
    Offline

    0
    ReputationRep:
    (Original post by kiiten)
    What do you need to know about it?

    Posted from TSR Mobile
    Hi,

    It's just general, i don't understand how to make the overall equations in redox, i struggle with it, i can do the first half equation bit for example,

    Al+3 -> Al+ + 3e- , however i am unable to do the overall equations could you give some examples and explain on how to do it please.

    Thank you Kitten

    x
    Offline

    17
    ReputationRep:
    (Original post by farihak97)
    Hi,

    It's just general, i don't understand how to make the overall equations in redox, i struggle with it, i can do the first half equation bit for example,

    Al+3 -> Al+ + 3e- , however i am unable to do the overall equations could you give some examples and explain on how to do it please.

    Thank you Kitten

    x
    Yeah sure, ill try find some examples for tomorrow

    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    Hi.
    Could someone explain to me how to draw complexes with a coordination number of 6.
    Offline

    17
    ReputationRep:
    (Original post by farihak97)
    Hi,

    It's just general, i don't understand how to make the overall equations in redox, i struggle with it, i can do the first half equation bit for example,

    Al+3 -> Al+ + 3e- , however i am unable to do the overall equations could you give some examples and explain on how to do it please.

    Thank you Kitten

    x
    Consider the equations:

    Cl2 + 2e- -----> 2Cl-
    Fe2+ -------> Fe3+ + e-

    Do you understand what is happening in both these half equations? If so how would you combine for a redox equation (ill tell you if you go wrong)

    Posted from TSR Mobile
    Offline

    1
    ReputationRep:
    A mixture of 1 mole of ethanoic acid, 2 moles of ethanoic and 1 mole of water was allowed to reach EQM. On analysis, the EQM mixture was found to contain 0.257 mole of ethanoic acid. Find Kc for the reaction...CH3C00H+C2H5OH----><----CH3C00C2H5+ H20

    The answer I get is 1.31, my tutor says it's '4 something'. Please help
    Offline

    0
    ReputationRep:
    Okay, Thank you so much. Unfortunately i don't know how to do it.ACE- i know that i'm meant to look at the atom, then the charges and finally the electrons.Could you, please show me how to make the overall question with this question, I know the first part of the half equation, which isFe2+ Fe3+ + 1e-How do you work out the second half equation and the overall.Thank you so much for helping me Kiiten means a lotFe2+ + MnO4- Fe3+ + Mn2+Please help.

    (Original post by kiiten)
    Consider the equations:

    Cl2 + 2e- -----> 2Cl-
    Fe2+ -------> Fe3+ + e-

    Do you understand what is happening in both these half equations? If so how would you combine for a redox equation (ill tell you if you go wrong)

    Posted from TSR Mobile
    Offline

    17
    ReputationRep:
    (Original post by farihak97)
    Okay, Thank you so much. Unfortunately i don't know how to do it.ACE- i know that i'm meant to look at the atom, then the charges and finally the electrons.Could you, please show me how to make the overall question with this question, I know the first part of the half equation, which isFe2+ Fe3+ + 1e-How do you work out the second half equation and the overall.Thank you so much for helping me Kiiten means a lotFe2+ + MnO4- Fe3+ + Mn2+Please help.
    No problem

    I think you're getting the method confused. First, we need to balance the electrons in order to combine them to make a redox equation. Cl2 + 2e- -----> 2Cl- has 2e- but Fe2+ -------> Fe3+ + e- has 1 electron. So you need to multiply the second equation by 2 to get 2Fe2+ -------> 2Fe3+ + 2e-

    Now you can combine the equations. Starting with the reactants: the 2e- cancel out (because they're on opposite sides of the arrow) leaving you with Cl2 + 2Fe2+ as the reactants. Same with the products, just add the 2Fe3+ + 2Cl-

    This gives you a final equation of:
    Cl2 + 2Fe2+ ------------> 2Fe3+ + 2Cl-

    Make sense?
    Offline

    2
    ReputationRep:
    Hi guys,
    Is there any technique you guys use when doing Nmr questions ( all analysis questions really)? I usually end up getting the right answers but I just take too much time (usually 25-30 mins for a question) lol - I'm worried I wont be able to finish on time in the exams
    Offline

    0
    ReputationRep:
    Thank you so much, that makes so much sense, i tried a few questions and i checked the answers and they were right. Thank you so so much.



    (Original post by kiiten)
    No problem

    I think you're getting the method confused. First, we need to balance the electrons in order to combine them to make a redox equation. Cl2 + 2e- -----> 2Cl- has 2e- but Fe2+ -------> Fe3+ + e- has 1 electron. So you need to multiply the second equation by 2 to get 2Fe2+ -------> 2Fe3+ + 2e-

    Now you can combine the equations. Starting with the reactants: the 2e- cancel out (because they're on opposite sides of the arrow) leaving you with Cl2 + 2Fe2+ as the reactants. Same with the products, just add the 2Fe3+ + 2Cl-

    This gives you a final equation of:
    Cl2 + 2Fe2+ ------------> 2Fe3+ + 2Cl-

    Make sense?
    Offline

    0
    ReputationRep:
    (Original post by shiney101)
    So what would you call this reaction?
    it is an equilibrium reaction because the ions exist in different solutions. The yellow chromate ion CrO42- is only stable in alkali solutions, while the orange dichromate ion Cr2O72- is stable in acid solutions (which is why you need to add H+ ions)
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: April 22, 2018
Poll
Do you like carrot cake?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.