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    (Original post by C0balt)
    Ah so further apart the electron the less attraction there is so less ionisation energy and all that argument

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    Yep

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    Thanks for the new knowledge
    I really love knowing the connection between chemistry and physics, which is why I'm applying for Chemical Physics :yep:

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    What would you guys say the biggest source of your potential errors are when performing titrations?

    Perhaps using a pipette and not getting the meniscus on the line! ?

    How much of a difference could this possibly make....
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    (Original post by wednesday_adams)
    What would you guys say the biggest source of your potential errors are when performing titrations?

    Perhaps using a pipette and not getting the meniscus on the line! ?

    How much of a difference could this possibly make....
    I'd say probably the biggest source of error is the human error of stopping exactly at the end point. It's very east to go past the endpoint. The meniscus and pipette do have an effect though as well

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    Hi does anyone know the group 2 compound which is insoluble in water and gives of co2 and White sold when reacted with sulfuric acid?


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    How would I calaculate this; concentration of NAOH was 0.100 moldm^-3, where the average titre is X to work the amount in moles of HCL in a volumentric flask..? Looking for calc
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    (Original post by Nidfeo)
    Do you know the volume of the flask?
    250 cm^3
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    (Original post by Uwaiss)
    How would I calaculate this; concentration of NAOH was 0.100 moldm^-3, where the average titre is X to work the amount in moles of HCL in a volumentric flask..? Looking for calc
    Mol=conc x vol

    Conc is 0.1 and volume is X. Put X in dm3 by dividing by 1000.

    Mol=0.1 x (X in dm3)

    That is moles of NaOH. Since it's 1:1 ratio the moles of NaOH equals moles HCl.

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    (Original post by Dylann)
    Mol=conc/vol

    Conc is 0.1 and volume is X. Put X in dm3 by dividing by 1000.

    Mol=0.1/(X in dm3)

    That is moles of NaOH. Since it's 1:1 ratio the moles of NaOH equals moles HCl.

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    My average titre if I was reckon was 30.9 would the calc be.. 0.1 / 0.0309? which is 3.09x10^-3?
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    (Original post by Nidfeo)
    Sorry, I can't help you with ISA
    Its from my CGP revision guide; shall I take a pic?
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    (Original post by Dylann)
    Mol=conc/vol

    Conc is 0.1 and volume is X. Put X in dm3 by dividing by 1000.

    Mol=0.1/(X in dm3)

    That is moles of NaOH. Since it's 1:1 ratio the moles of NaOH equals moles HCl.

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    n = cV not c/V

    Think in units:
    If moldm^-3/dm^3 was the case the ending unit would be moldm^-6 which is ridiculous.

    edit: oops didn't know you're year 13 x.x sorreh
    take this as a clarification for the original poster
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    (Original post by C0balt)
    n = cV not c/V

    Think in units:
    If moldm^-3/dm^3 was the case the ending unit would be moldm^-6 which is ridiculous.
    Don't start on my *****, probs was just a typing error
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    (Original post by Chocofudge123)
    Hi does anyone know the group 2 compound which is insoluble in water and gives of co2 and White sold when reacted with sulfuric acid?


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    Calcium carbonate?
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    (Original post by frozo123)
    Don't start on my *****, probs was just a typing error
    well he did it twice
    better be safe than doing it again in exam
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    (Original post by C0balt)
    well he did it twice
    better be safe than doing it again in exam
    he's in year 13
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    (Original post by frozo123)
    he's in year 13
    lol didn't notice
    anyways for the benefit of the person who was asking :P
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    (Original post by Uwaiss)
    My average titre if I was reckon was 30.9 would the calc be.. 0.1 / 0.0309? which is 3.09x10^-3?

    (Original post by C0balt)
    n = cV not c/V

    Think in units:
    If moldm^-3/dm^3 was the case the ending unit would be moldm^-6 which is ridiculous.

    edit: oops didn't know you're year 13 x.x sorreh
    take this as a clarification for the original poster
    Wow I must have been half asleep when I wrote that! You're dead right, it's mol = conc x vol not conc/vol! mol = mass/mr

    haha, we all make mistakes

    Sorry Uwais, so yeah mol = conc x vol

    conc = 0.01
    vol = X

    mol = 0.01 x X in dm-3
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    (Original post by frozo123)
    he's in year 13
    Doesn't mean I'm immune from making silly mistakes
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    (Original post by Dylann)
    Doesn't mean I'm immune from making silly mistakes
    Never said you were
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    hi guys I've had this nagging problem in chem for a while
    say in the empa it asks you to work out a given value
    say it comes to 109.89088987
    `i round that to 3sf to get 110

    Then in part(ii) it asks me hence to work out say percentage error for 100 the true value
    Do i sub in my rounded answer of 110 or my accurate answer of 109.89088987 to get my answer for this part (ii) answer
    thanks this has been annoying me for ages becos using my rounded answer could introduce rounding errors
 
 
 
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