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    (Original post by Dylann)
    Physical chemistry is definitely my favourite too and okay sorry, no more shall be asked
    We can discuss it over PM once you're done
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    Has anyone done there as chemistry A evalu isas

    It would be so nice if i could get suggestions,tips and advive asap ive gotmines on wednesday also you can contact me on watsapp about it on 07450464028
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    (Original post by Xin Xang)
    Anyone here doing the chemistry olympiad ?
    Yep! only been told today though ( and I need to learn all of A2 now ugh
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    (Original post by Dinaa)
    Hello AS Chemistry TSRians!

    I thought it would be a good idea to make a thread, where students doing AS Chemistry, post/ask questions, and we could all help each other out?

    Teaching another person, also helps you become more confident and you both develop a better understanding. I know there is an A-level chat thread already, but this should be for learning!

    There is no such thing as a silly question, so ask away and hopefully, you'll find someone who can help you

    I shall also make a list of the Chemistry students, and what exam board they're all on! So please post what exam board you are on, if you are in!

    List of the students doing Chemistry!

    Spoiler:
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    Lovely helpers!

    Spoiler:
    Show










    I apologize if I've missed anyone out, got the list from Current year 12 list! (Lazy i know) :mmm:

    P.S- If you don't want to, okay, you are not obliged to do so! But please, no rude/offensive comments

    :elefant::elefant::elefant::elefant::elefant::elefant::elefant::elefant::elefant::elefant:
    Add me on please AQA
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    Okay, my first geniune Chemistry question :teehee:

    Question:
    The oxygen atom in water has two lone pairs of electrons. Suggest why the ion H4O2+ is not generally formed in acidic solutions that contain H+ ions.
    Now, I understand that this is related to the effect of lone pairs of Oxygen and that two hydrogens in the ion form dative covalent bonds with the Oxygen and the other two hydrogen atoms in the ion form normal covalent bonds with Oxygen but I don't know to link that into the the question

    Does it have anything related to the change of the shape of the ion and therefore the knock-on effect of becoming a non-polar molecule?

    Can someone explain?

    Thank you
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    (Original post by zhang-liao)
    Okay, my first geniune Chemistry question :teehee:

    Question:


    Now, I understand that this is related to the effect of lone pairs of Oxygen and that two hydrogens in the ion form dative covalent bonds with the Oxygen and the other two hydrogen atoms in the ion form normal covalent bonds with Oxygen but I don't know to link that into the the question

    Does it have anything related to the change of the shape of the ion and therefore the knock-on effect of becoming a non-polar molecule?

    Can someone explain?

    Thank you
    Interesting question...probably because if there are H+ ions floating about they are likely to be attacked by water rather than by H3O+ ions. Also, H3O+ is a postive ion, and joining together two positive ions (h+ and h3o+) may cause some repulsion and thus be very unstable when actually formed (and thus split back into h3o+ and h+ ions)
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    (Original post by Dylann)
    Interesting question...probably because if there are H+ ions floating about they are likely to be attacked by water rather than by H3O+ ions. Also, H3O+ is a postive ion, and joining together two positive ions (h+ and h3o+) may cause some repulsion and thus be very unstable when actually formed (and thus split back into h3o+ and h+ ions)
    Yeah but would there be any relation to intermolecular bonding though?

    Quite a strange question to ask though
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    Which is more stable cyclohexane or benzene?
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    (Original post by zhang-liao)
    Yeah but would there be any relation to intermolecular bonding though?

    Quite a strange question to ask though
    Well I would assume all the bonds in H4O2+ would be covalent, or at least dative covalent, and not to with intermolecular forces. But it's a good question and I'll ask a teacher or someone (you should do, and compare answers)

    (Original post by louisaerin)
    Which is more stable cyclohexane or benzene?
    Benzene because the delocalised ring structure is very stable. You sure this is AS?
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    (Original post by Dylann)
    Well I would assume all the bonds in H4O2+ would be covalent, or at least dative covalent, and not to with intermolecular forces. But it's a good question and I'll ask a teacher or someone (you should do, and compare answers)



    Benzene because the delocalised ring structure is very stable. You sure this is AS?
    Thank you I am doing AS chemistry and this question was on my assignment this week
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    (Original post by Gott)
    I'm doing OCR AS

    How many assessed practicals have people done, I've done 1 qual 1 quant?
    hey I've done one eval one quant
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    (Original post by noshahmad)
    I am doing OCR salter chemistry and would be more than happy to help granted I've learnt the content myself

    Posted from TSR Mobile
    Would you be able to help me if I ask you a few questions ?
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    (Original post by Dylann)
    Interesting question...probably because if there are H+ ions floating about they are likely to be attacked by water rather than by H3O+ ions. Also, H3O+ is a postive ion, and joining together two positive ions (h+ and h3o+) may cause some repulsion and thus be very unstable when actually formed (and thus split back into h3o+ and h+ ions)
    H+ doesn't exist only the hydroxonium ion though? And there's an additional oxygen in the molecule posted before? As in h4o2 not h4o


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    (Original post by cerlohee)
    H+ doesn't exist only the hydroxonium ion though? And there's an additional oxygen in the molecule posted before? As in h4o2 not h4o


    Posted from TSR Mobile
    I think the 2 was the charge, so it's basically a water molecule with 2 extra hydrogens. H4O2+. And you're right, the H+ floating about (from the acid) will be attacked by water instantly, so h3o+ will form. But I think it's unlikely the h3o+ will attack h+ due to replusion and instability

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    (Original post by louisaerin)
    Which is more stable cyclohexane or benzene?
    Thermodynamically, cyclohexane is more stable than benzene.
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    (Original post by l1lvink)
    Thermodynamically, cyclohexane is more stable than benzene.
    Why?

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    I'm going to admit that I didn't know the answer, so I looked it up. This appears to be the answer:


    All six carbon atoms in benzene are sp2 hybridized. The two sp2 hybrid orbitals of each carbon atom overlap with the sp2 hybrid orbitals of adjacent carbon atoms to form six sigma bonds in the hexagonal plane. The remaining sp2 hybrid orbital on each carbon atom overlaps with the s-orbital of hydrogen to form six sigma C–H bonds. The remaining unhybridized p-orbital of carbon atoms has the possibility of forming threeC bonds by the lateral overlapping.
    The six π’s are delocalized and can move freely about the six carbon nuclei. Even after the presence of three double bonds, these delocalized π-electrons stabilize benzene.[ π cloud] about cyclohexene and cyclohexane both are more saturated than benzene but they have specific structures and can only be present in that form only but for benzene it not only has the extensive π cloud but also resonating structures so it can remain in any one of those structures so it is more stable in terms of entropy..Not only benzene but also many other substances show these properties they are broadly classified as AROMATIC COMPOUNDS..
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    Heya so I have a quant isa on Tue on observations and balanced symbol equations. Any help? Im crap at isas
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    (Original post by l1lvink)
    I'm going to admit that I didn't know the answer, so I looked it up. This appears to be the answer:


    All six carbon atoms in benzene are sp2 hybridized. The two sp2 hybrid orbitals of each carbon atom overlap with the sp2 hybrid orbitals of adjacent carbon atoms to form six sigma bonds in the hexagonal plane. The remaining sp2 hybrid orbital on each carbon atom overlaps with the s-orbital of hydrogen to form six sigma C–H bonds. The remaining unhybridized p-orbital of carbon atoms has the possibility of forming threeC bonds by the lateral overlapping.
    The six π’s are delocalized and can move freely about the six carbon nuclei. Even after the presence of three double bonds, these delocalized π-electrons stabilize benzene.[ π cloud] about cyclohexene and cyclohexane both are more saturated than benzene but they have specific structures and can only be present in that form only but for benzene it not only has the extensive π cloud but also resonating structures so it can remain in any one of those structures so it is more stable in terms of entropy..Not only benzene but also many other substances show these properties they are broadly classified as AROMATIC COMPOUNDS..
    Yeah that makes sense. I think if you compare the thermodynamic properties as you said, it could suggest cyclohexane is more stable, since cyclohexane has a enthalpy of formation of about -170 and benzene has +50. Though this doesn't necessarily indicate stability as the part you quoted talks about overlapping of orbitals which is actually more to do with stability than enthalpies.
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    (Original post by kira1)
    Would you be able to help me if I ask you a few questions ?
    Sure
 
 
 
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