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    how please explain
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    (Original post by hum1)
    how please explain
    How you can work out how many isomers there are?

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    (Original post by grapes12)
    It is AQA and it is on titrations. (AS level)
    Make sure you know group 2 metals well too if it is the second isa
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    (Original post by BeckyWarkup)
    Make sure you know group 2 metals well too if it is the second isa
    It is the second ISA. What do I need to know about them? I didn't realise they fit into titrations except for Mg being the antacid tablet but everyone knows that
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    (Original post by samb1234)
    Cobalt there is an easier way if you're prepared to do a but of maths

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    I've googled before but never found anything useful?


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    (Original post by grapes12)
    It is the second ISA. What do I need to know about them? I didn't realise they fit into titrations except for Mg being the antacid tablet but everyone knows that
    On the outline it said amount of substance and group 2, we have the paper tomorrow and apparently it has identifying group 2 compounds from how they react
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    (Original post by grapes12)
    It is the second ISA. What do I need to know about them? I didn't realise they fit into titrations except for Mg being the antacid tablet but everyone knows that
    You could be made to do back titration. You could be asked about percentage purity of the tablet.

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    (Original post by C0balt)
    I've googled before but never found anything useful?


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    It just requires you to think about it. If you take the example of C8H17Cl. There are four different isomers you can get from a straight carbon chain for this case. There are then 3 different ways you could make a methyl heptane each of which would have another 4 isomers etc

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    (Original post by BeckyWarkup)
    On the outline it said amount of substance and group 2, we have the paper tomorrow and apparently it has identifying group 2 compounds from how they react
    Yeah my paper is tomorrow too, my teachers never mentioned anything about group 2 though. Urgh. Do you have any notes I could look at?

    (Original post by C0balt)
    You could be made to do back titration. You could be asked about percentage purity of the tablet.

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    I have no idea what back titrations are, I missed a whole pile of lessons due to personal reasons so really I am going into this blind
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    (Original post by samb1234)
    It just requires you to think about it. If you take the example of C8H17Cl. There are four different isomers you can get from a straight carbon chain for this case. There are then 3 different ways you could make a methyl heptane each of which would have another 4 isomers etc

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    Yeah but thats not very easy way as in plug numbers into formula and voila
    And then you have to base them on number of isomers of octane or whatever alkane which doesn't have formula to work out number of isomers

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    Have you guys done f322 past papers? What scores did y'all get

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    (Original post by C0balt)
    Yeah but thats not very easy way as in plug numbers into formula and voila
    And then you have to base them on number of isomers of octane or whatever alkane which doesn't have formula to work out number of isomers

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    Its easier than drawing the 30+ isomers this most likely has

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    (Original post by grapes12)
    I have no idea what back titrations are, I missed a whole pile of lessons due to personal reasons so really I am going into this blind
    Determining mass of Mg(OH)2 in antacid tablet through titration etc

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    (Original post by grapes12)
    Yeah my paper is tomorrow too, my teachers never mentioned anything about group 2 though. Urgh. Do you have any notes I could look at?



    I have no idea what back titrations are, I missed a whole pile of lessons due to personal reasons so really I am going into this blind
    We have done the practical and it is fine, the instructions on the sheet are easy to follow
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    (Original post by BeckyWarkup)
    We have done the practical and it is fine, the instructions on the sheet are easy to follow
    I did the practical today, it was good. Its the paper im stressing about
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    (Original post by C0balt)
    Determining mass of Mg(OH)2 in antacid tablet through titration etc

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    So that's moles x mr right?
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    (Original post by grapes12)
    I did the practical today, it was good. Its the paper im stressing about
    search www.a-levelchemistry.co.uk and go onto AQA Chemistry then AS Chemistry then go on to 3.2.6 and click on the link at the top of the page for group 2 notes, i use these because i have a useless teacher for some of it, including everything the isas have been on
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    Anyone who's done the titrations isa ? Holla at me i will be able to help you with the thermal decomposition of Zinc carbonate
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    (Original post by anonymous-97)
    Anyone who's done the titrations isa ? Holla at me i will be able to help you with the thermal decomposition of Zinc carbonate
    Oi fam

    Why you cheating for

    Shall i report you to the exam board so they can disqualify you

    Do you really want that to happen :hmmm:

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    (Original post by grapes12)
    So that's moles x mr right?
    Yes but not directly
    You would react the tablet with known amount of excess HCl. Mg OH)2 would react with HCl. Now then titrate the unreacted HCl with NaOH, from which you can reduce the number of moles of HCl unreacted. Now you can find the amount reacted with Mg(OH)2 by subtracting, then you can multiply Mr by n to work out the mass of Mg(OH)2 in the tablet. You can then be asked about percentage purity if you were given the mass of entire tablet.

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