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    Hi,

    I started doing my chemistry IA on the effect of temperature on buffering capacity. I added a pH 7 buffer to distilled water and titrated it with NaOH. I then measured the amount of NaOH taken to increase the pH of the water by a unit of 1. I tried this for temperatures between 5 and 80 degrees but there was no significant difference between the data obtained.*

    This there any notable fault in my methodology?

    I have to finish gathering data for my IA within one week. Since I was going to discuss the effect of temperature on the equilibria*of the buffer solution, I am in the process of finding another IA experiment in the same subject area.*

    If you have any suitable ideas or any improvements for my previous method, please let me know.

    Thank you*
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    Why do you think T should affect buffering capacity?
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    Because pKa is dependent on temperature because of its effect on equilibrium
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    Using ethanoic acid, Ka = 1.74e-5:
    A 1 dm3 mix with 1 mol dm-3 A- : 1 mol dm-3 HA mixture has a pH of 4.76. If OH- is added until the pH is 5.76, the mixture will have a A- : HA ratio of 10 : 1

    At a higher T Ka will be a higher value as the dissociation is endothermic. I just used 1.95e-5:
    A 1 dm3 mix with 1 mol dm-3 A- : 1 mol dm-3 HA mixture has a pH of 4.71. If OH- is added until the pH is 5.71, the mixture will have a A- : HA ratio of 10 : 1

    I don't think the volume of OH- needed would be any different at different values of T. Maybe I'm missing something.
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    Thank you, I'll give that a try.

    I would think that the disassociation constant would be different for the buffer at different temperatures, changing its ability to keep the ph of a solution at a particular value. the change might be too small to be measured with the addition of a base.
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    (Original post by NicknameTara)
    Thank you, I'll give that a try.

    I would think that the disassociation constant would be different for the buffer at different temperatures, changing its ability to keep the ph of a solution at a particular value. the change might be too small to be measured with the addition of a base.
    Ka changes with T, but I don't see it affecting its ability to resist pH change.
 
 
 
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