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Topic: buffers  (Read 4929 times)

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socomplicated

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buffers
« on: March 13, 2005, 05:09:25 AM »
to make a 25mM buffer with pH5.2 i add 25mM ethanoic acid with 25mM sodium ethanoate. after adjusting the pH, the buffer will still be 25mM. will this also be the case if i use 25 mM Tris-base and 25 mM phosphoric acid? will i still get a buffer with 25mM after adjusting the pH to 5.2 with the phosphoric acid?

the first one is a conjugate pair (ethanoic acid and sodium ethanoate), while the second one is not a conjugate pair (Tris-base and phosphoric acid)   :-\

thanks.
« Last Edit: March 13, 2005, 05:11:35 AM by socomplicated »

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Re:buffers
« Reply #1 on: March 13, 2005, 06:50:21 AM »
to make a 25mM buffer with pH5.2 i add 25mM ethanoic acid with 25mM sodium ethanoate. after adjusting the pH, the buffer will still be 25mM. will this also be the case if i use 25 mM Tris-base and 25 mM phosphoric acid? will i still get a buffer with 25mM after adjusting the pH to 5.2 with the phosphoric acid?

The key question is: how is the buffer molarity defined?
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socomplicated

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Re:buffers
« Reply #2 on: March 13, 2005, 07:04:06 AM »
The key question is: how is the buffer molarity defined?
i know how to calculate the buffer molarity, but in some cases  i don't have time to do it, but only have to be sure, so my question is i know that a conjugate pair act that way, but how about a non conjugate pair? do you know it?

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