ammonium acetate buffer

[olivia]

Hi, can I make 0.2M ammonium acetate buffer at pH 5.5 using ammonium acetate and acetic acid?
Can someone please help with the calculation? I weighed out 15.2g of ammonium acetate I took the pH of ammonium acetate in water to be 7 and adjusted the pH to 6 with acetic acid. Is this right?
Thank you
Olivia

[HW Mueller]

Generally, check

http://www.liv.ac.uk/buffers/buffercalc.html

(If I remember there is no calc. for NH4OAc there, though)..

One can do what you did, but repeating it could be difficult. If you prepare a 0.2 M acetic acid and mix this with your NH4OAc you keep at least the acetate concentration constant. (My calc. for 0.2 moles/L is 15.4g NH4OAc.)

[bookoon]

you may also try the following site

http://www.egr.msu.edu/scb-group/tools/