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    Please anyone answer me, what does INTERMEDIATE mean in intermediate bonding and also homogeneous catalysts work by forming intermediates??:confused:
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    (Original post by thymolphthalein)
    7 marks?:eek:

    I'm still awake for some reason, so I'll try answering this.

    When sunlight hits the earth, some of it is re-emitted back as infra red radiation.

    Only gases with polar bonds such as water vapour or carbon oxide can absorb this infra-red radiation.To achieve this, the molecule changes its own dipole moment during the vibration/bending of bonds in the molecule.

    These gases in the air trap the re-emitted radiation, causing the atmosphere of the Earth to heat up. This effect is known as the green house effect and the gases responsible for this are known as green house gases.

    The increased concentration of known greenhouse gases and the introduction of new greenhouse gases due to human activity has led to a much greater amount of radiation being trapped causing an increase in the temperature of the Earth's atmosphere. This increase in air temperature is known as global warming.

    I tried.
    thank u sooosoo much
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    (Original post by mismash)
    thank u sooosoo much
    No problem.

    Without a mark scheme, it's hard to say whether I mentioned irrelevant points and missed a necessary point. So if you have one, you should check.

    That aside, I'm pretty sure it would get at least 5 marks.
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    (Original post by thymolphthalein)
    7 marks?:eek:

    I'm still awake for some reason, so I'll try answering this.

    When sunlight hits the earth, some of it is re-emitted back as infra red radiation.

    Only gases with polar bonds such as water vapour or carbon oxide can absorb this infra-red radiation.To achieve this, the molecule changes its own dipole moment during the vibration/bending of bonds in the molecule.

    These gases in the air trap the re-emitted radiation, causing the atmosphere of the Earth to heat up. This effect is known as the green house effect and the gases responsible for this are known as green house gases.

    The increased concentration of known greenhouse gases and the introduction of new greenhouse gases due to human activity has led to a much greater amount of radiation being trapped causing an increase in the temperature of the Earth's atmosphere. This increase in air temperature is known as global warming.

    I tried.
    Maybe mention how they trap ir. The molecule absorbs ir and then re-emitts it back towards earth.

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    (Original post by samb1234)
    Maybe mention how they trap ir. The molecule absorbs ir and then re-emitts it back towards earth.

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    Didn't I do that?

    I mentioned that the IR radiation is absorbed due to vibration/bending of polar bonds and the re-emission is also mentioned. I've learnt not to miss that word because the mark scheme requires it to get the mark.
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    Does both sentences mean the same thing?? HBr is oxidised by the H2SO4 and HBr reduce the H2SO4
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    (Original post by FluffyCherry)
    Does both sentences mean the same thing?? HBr is oxidised by the H2SO4 and HBr reduce the H2SO4
    Yeah, pretty much.

    If something is being oxidized, it is reducing the other.species.
    If something is being reduced, is is oxidizing the other species.
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    (Original post by thymolphthalein)
    Yeah, pretty much.

    If something is being oxidized, it is reducing the other.species.
    If something is being reduced, is is oxidizing the other species.
    yeaah, Thnx once again!!
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    (Original post by thymolphthalein)
    Didn't I do that?

    I mentioned that the IR radiation is absorbed due to vibration/bending of polar bonds and the re-emission is also mentioned. I've learnt not to miss that word because the mark scheme requires it to get the mark.
    You mentioned that the ir it absorbs was reflected/re-emitted from the earths surface. But you didn't mention that the greenhouse gases absorb this ir and then re-emitt back towards earth

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    (Original post by samb1234)
    You mentioned that the ir it absorbs was reflected/re-emitted from the earths surface. But you didn't mention that the greenhouse gases absorb this ir and then re-emitt back towards earth

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    I'll add it then.
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    Attachment 413557

    Hi, my revision guide says this but the reactions don't show the hydroxide ions reacting with the acids from the reaction Cl2+H20->HCl +HClO? Are the equations misplaced? Or does this not happen at all?
    Also when you get a solid sodium halide reacting with sulphuric acid and have to write an ionic equation, why do you have to split up the halide into it's ions when it is a solid so shouldn't be split up usually?
    Thanks
    Rep will be given to anyone who can help
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    Ugh , feel like i can't even get a B . I would revise the content , but cant apply it to the questions properly. Any advice?
    • Welcome Squad
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    (Original post by tflanjee)
    Attachment 413557

    Hi, my revision guide says this but the reactions don't show the hydroxide ions reacting with the acids from the reaction Cl2+H20->HCl +HClO? Are the equations misplaced? Or does this not happen at all?
    Also when you get a solid sodium halide reacting with sulphuric acid and have to write an ionic equation, why do you have to split up the halide into it's ions when it is a solid so shouldn't be split up usually?
    Thanks
    Rep will be given to anyone who can help
    Attachment seems to be invalid


    The sodium halide is a salt which dissociates so it becomes aqueous and therefore splits up into its constituent ions btw

    (Original post by TSR Mustafa)
    Ugh , feel like i can't even get a B . I would revise the content , but cant apply it to the questions properly. Any advice?
    Loads of exam practice will help you understand where the marks comes from. Looks at examiner tips in examiner reports too
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    Can someone check this please:

    Rate of hydrolysis of halogenoalkanes increases down group 7 because bond enthalpy decreases. Decrease in bond enthalpy is due to the increase in atomic radius of the halogen and a fall in electronegativity down group 7.


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    (Original post by clara16)
    Can someone check this please:

    Rate of hydrolysis of halogenoalkanes increases down group 7 because bond enthalpy decreases. Decrease in bond enthalpy is due to the increase in atomic radius of the halogen and a fall in electronegativity down group 7.


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    Spot on.
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    (Original post by clara16)
    Can someone check this please:

    Rate of hydrolysis of halogenoalkanes increases down group 7 because bond enthalpy decreases. Decrease in bond enthalpy is due to the increase in atomic radius of the halogen and a fall in electronegativity down group 7.


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    All right except the very last bit. Decrease in electro negativity would actually increase the bond enthalpy but the effect of it is greatly outweighed by increasing bond length
    Get rid of electronegativity bit and it is perfect
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    How do you draw the E-isomer of 3-methylpent-2-ene?
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    You will not be asked to draw an isomer and assign it. You only need to recognise the possibility of E and Z isomers in complex double bonds. You have to be able to distinguish between cis and trans.
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    (Original post by TeachChemistry)
    You will not be asked to draw an isomer and assign it. You only need to recognise the possibility of E and Z isomers in complex double bonds. You have to be able to distinguish between cis and trans.
    There was a question on AQA where you had to draw it out. June 2010 chem 2 I think
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    (Original post by Super199)
    There was a question on AQA where you had to draw it out. June 2010 chem 2 I think
    Fair enough. I teach OCR and you would not have to do it for that board.
 
 
 
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