http://www.collegeboard.com/student/testing/ap/chemistry/samp.html Click the scoring guidelines link for your year. There will be answers etc.
I figured out the answers to number 1 a, b, and c. I still haven't figured out d.a) Ka=[H+][C3H5O3-] / [HC3H5O3], Ka= .00014b) pH=2.08c) pH=3.41If you figure out d, let me know c:d) [C3H5O3-]= .0007M
The question has just been release so the answers should also be release as soon as possible, if not keep looking gg gg gg gg gg gg
http://apcentral.collegeboard.com/apc/public/repository/ap08_statistics_sgs.pdf
http://www.collegeboard.com/prod_downloads/ap/students/chemistry/ap04_sg_chem.pdf http://www.collegeboard.com/prod_downloads/ap/students/chemistry/ap04_sg_b_chem.pdf
http://apcentral.collegeboard.com/apc/public/repository/_ap06_chemistry_sg.pdf