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Edexcel - Chemistry Unit 2 - 4 June 2013 Watch

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    Just post any questions you have here, and people will answer[/QUOTE]


    I have a problem when it comes to major peaks and differences between two molecules in mass spectrum , any notes will help me a lot , thanks
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    (Original post by airheadbuster)
    B.

    Strontium ion gives a red/crimson colored flame. With concentrated H2SO4, HCL forms which reacts with moisture in air to give steamy white fumes.
    thank you

    any advice for remembering important equations and what they form and which you think are most important?
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    (Original post by SKK94)
    **The tertiary carbocation formed during nucleophilic substitution is more stable than a secondary or primary carbocation**
    Tertiary halogenoalkanes are more reactive, because the stable tertiary carbocation is formed as an intermediate.
    What do you mean? :eek:
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    (Original post by Juliajuliajulia)
    Because they're more stable they're more likely to form therefore most reactive that make sense?
    Ohhh, okay. I think I understand now. Thank you
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    HCl HBr and HI are soluble in water and form strong acids. Why does the acidity get stronger as the atom gets larger??
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    (Original post by Blanche001)
    HCl HBr and HI are soluble in water and form strong acids. Why does the acidity get stronger as the atom gets larger??
    Because the electronegativity gets larger and the bond gets weaker.

    Weaker bond = more H+ ions

    (Original post by kathspicer)
    can some give me tips on how to do redox reactions, my teacher left half way through the course and I dont really understand how to do them
    It's easier if you just post questions here, so someone can help you
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    Can you please give me tips on how to fund mass of peak in mass spectrometer
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    (Original post by Blanche001)
    HCl HBr and HI are soluble in water and form strong acids. Why does the acidity get stronger as the atom gets larger??
    Because the halides become stronger reducing agents down the group.
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    (Original post by posthumus)
    Because the electronegativity gets larger and the bond gets weaker.

    Weaker bond = more H+ ions



    It's easier if you just post questions here, so someone can help you
    why does that mean more H+ ions?
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    (Original post by airheadbuster)
    Tertiary carbocations are most stable. Tertiary halogenoalkanes are indeed most reactive.
    tertiary carbocations aren't more stable. tertiary carbocations are a more stable intermediate. tertiary haloalkanes are the most reactive because the carbocation is more stable (more +ve) easy for leaving group to leave
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    (Original post by Blanche001)
    why does that mean more H+ ions?
    It dissociates the H+ more easily leading to more h+ ions and acids are h+ ion donors
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    (Original post by posthumus)
    Because the electronegativity gets larger and the bond gets weaker.

    Weaker bond = more H+ ions
    H-X (X= halide) bond gets stronger down the group (HF is an exception).

    Edit: This one is wrong. It's the intermolecular forces that gets stronger.
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    (Original post by Goods)
    It dissociates the H+ more easily leading to more h+ ions and acids are h+ ion donors
    oh god, never mind thanks for all replying!
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    (Original post by airheadbuster)
    H-X (X= halide) bond gets stronger down the group (HF is an exception).
    .... the bond gets weak the intermolecular forces get stronger.... do you even chemistry bro?
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    When excess calcium is added to water, effervescence occurs and
    A a clear colourless solution is formed.
    B a cloudy suspension is formed.
    C an orange-red flame is seen.
    D a yellow flame is seen.

    answers b - why? please can anyone help me




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    (Original post by Goods)
    tertiary carbocations aren't more stable. tertiary carbocations are a more stable intermediate. tertiary haloalkanes are the most reactive because the carbocation is more stable (more +ve) easy for leaving group to leave
    I thought the reactivity was determined in terms of intermolecular force strength and ya, tertiary carbocations are a more stable intermediate.
    Could you please explain a bit more?
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    (Original post by Goods)
    .... the bond gets weak the intermolecular forces get stronger.... do you even chemistry bro?
    Oh ya, my bad. It's the intermolecular forces that gets stronger.
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    (Original post by airheadbuster)
    H-X (X= halide) bond gets stronger down the group (HF is an exception).
    Nope, it gets weaker ! I'm talking about intramolecular forces by the way not intermolecular


    Also does anyone know if all halogenoalkanes are soluble ???
    All amines are right ??? dude to hydrogen bonding
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    (Original post by Hi, How are you ?)
    So why is HF only able to for 1 hydrogen bond when it has 3 lone pair of e-?
    Because there is only 1 hydrogen!

    Imagine 10 HF molecules, there can only be 10 hydrogen bonds not 30 :P
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    (Original post by posthumus)
    Nope, it gets weaker ! I'm talking about intramolecular forces by the way not intermolecular


    Also does anyone know if all halogenoalkanes are soluble ???
    All amines are right ??? dude to hydrogen bonding
    Not soluble in water. Soluble in only alcoholic solution.
 
 
 
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