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    Hi, I just started year 12.

    I had done a titration at school I used 2.10g of sodium hydrogen-carbonate and used 250ml of the sodium hydrogen-carbonate and water solution.

    of 30.45I got an average titration of 30.45

    Could you answer the questions I dont understand (2, and 4), and can you check some of my answers

    1.The balance has a maximum of uncertainty of +- 0.005g in each reading. Calculate the percentage uncertainty in your mass of sodium hydrogen carbonate.

    my answer: Would this be (0.005/2.10)x100 = +-0.2%


    2. Explain why hydrated sodium carbonate and sodium hydroxide are not appropraite bases for making up a standard solution

    3. The burette has a maximum uncertainty of +-0.05 cm^3 in each reading. Calculate the percentage uncertainty in your first accurate titre. (my first accurate titre was 30.40cm^3)

    my answer: (0.05/30.40)x100 = +- 0.2%

    4. The volumetric flask has a maximum uncertainty of +-0.3cm^3 and the pipette has a maximum uncertainty of +-0.04cm^3. Which of these gives the larger percentage uncertainty .


    Thank you!!
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    Hi, I just started year 12.

    I had done a titration at school I used 2.10g of sodium hydrogen-carbonate and used 250ml of the sodium hydrogen-carbonate and water solution.

    of 30.45I got an average titration of 30.45

    Could you answer the questions I dont understand (2, and 4), and can you check some of my answers

    1.The balance has a maximum of uncertainty of +- 0.005g in each reading. Calculate the percentage uncertainty in your mass of sodium hydrogen carbonate.

    my answer: Would this be (0.005/2.10)x100 = +-0.2%


    2. Explain why hydrated sodium carbonate and sodium hydroxide are not appropraite bases for making up a standard solution

    3. The burette has a maximum uncertainty of +-0.05 cm^3 in each reading. Calculate the percentage uncertainty in your first accurate titre. (my first accurate titre was 30.40cm^3)

    my answer: (0.05/30.40)x100 = +- 0.2%

    4. The volumetric flask has a maximum uncertainty of +-0.3cm^3 and the pipette has a maximum uncertainty of +-0.04cm^3. Which of these gives the larger percentage uncertainty .


    Thank you!!
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    (Original post by Frank Peters)
    Hi, I just started year 12.

    I had done a titration at school I used 2.10g of sodium hydrogen-carbonate and used 250ml of the sodium hydrogen-carbonate and water solution.

    of 30.45I got an average titration of 30.45

    Could you answer the questions I dont understand (2, and 4), and can you check some of my answers

    1.The balance has a maximum of uncertainty of +- 0.005g in each reading. Calculate the percentage uncertainty in your mass of sodium hydrogen carbonate.

    my answer: Would this be (0.005/2.10)x100 = +-0.2%


    yes



    2. Explain why hydrated sodium carbonate and sodium hydroxide are not appropraite bases for making up a standard solution


    They are not stable in the atmosphere. Sodium carbonate effloresces and sodium hydroxide is both deliquescent and reacts with carbon dioxide. All of the above change the mass.



    3. The burette has a maximum uncertainty of +-0.05 cm^3 in each reading. Calculate the percentage uncertainty in your first accurate titre. (my first accurate titre was 30.40cm^3)

    my answer: (0.05/30.40)x100 = +- 0.2%



    No. You take two readings on a burette for each titre, so the absolute error is ñ 0.1 ml



    4. The volumetric flask has a maximum uncertainty of +-0.3cm^3 and the pipette has a maximum uncertainty of +-0.04cm^3. Which of these gives the larger percentage uncertainty .


    Thank you!!
    Work out the % inaccuracy of both!
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    (Original post by charco)
    [/b]

    yes



    They are not stable in the atmosphere. Sodium carbonate effloresces and sodium hydroxide is both deliquescent and reacts with carbon dioxide. All of the above change the mass.



    No. You take two readings on a burette for each titre, so the absolute error is ñ 0.1 ml

    [b]

    Work out the % inaccuracy of both!

    I dont understand the question about sodium carbonate and sodium hydroxide though
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    (Original post by Frank Peters)
    I dont understand the question about sodium carbonate and sodium hydroxide though
    If you have a compound which changes mass randomly in the atmosphere how do you know how much of it you are actually weighing out?

    They are not stable in the atmosphere. Sodium carbonate effloresces and sodium hydroxide is both deliquescent and reacts with carbon dioxide. All of the above change the mass.

    Did you bother to look up the terms effloresce and deliquesce?
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    (Original post by charco)
    If you have a compound which changes mass randomly in the atmosphere how do you know how much of it you are actually weighing out?

    They are not stable in the atmosphere. Sodium carbonate effloresces and sodium hydroxide is both deliquescent and reacts with carbon dioxide. All of the above change the mass.

    Did you bother to look up the terms effloresce and deliquesce?

    effloresce means to lose water of crystillisation, deliquesce means to dissolve in a liquid.
    Effloresce means to lose water of crystillisation and deliquesce means to dissolve in a liquid (in this case the water from the atmosphere dissolves the sodium hydroxide)
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    Thanks sophia great answer
 
 
 
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