need some ap chem help please!!?

Question

I have this howmework assignment and i really need some help on it.

I am given the graph of a weak acid storng base titration. (25mL of 0.1M solution of weak acid is titrated by 0.1M NaOH.)

Part of the question asks me to describe one method by which the value of the acid-dissociation constant for HA (the unknown weak acid) can be determined from the graph. How in the world do I do this?

Another part of the question says= "a 25mL sample of 0.1M HA(unknown weak acid) is titrated with a 0.2M NaOH." Then it asks me to find the volume that must be added to reach the equivalence point. And once again how the heck do i do that.

Finally, last question i promise. one again "a 25mL sample of 0.1M HA(unknown weak acid) is titrated with a 0.2M NaOH."
Now it asks me why the pH at the equivalence point for this titration is slightly higher than the pH at the equivalence point in the titration using 0.1 M NaOH.

Please help me!! GIve me some hints or steps on how to calculate these

Answer 1

Sorry, I'm going into AP Chem next year, but I would appreciate it if you can tell me the name of your book and ISBN number. Like post it on your question.
Sorry that I can't help you.

Answer 2

alright, i just did this lab, but its really hard to explain. so idk if u have AIM or yahoo it would be easier because then i could know your data and stuff, otherwise i can do my best do it through email (because well need your numbers to figure the stuff out)

if u want to email me go right ahead, [e-mail]