Calculating pH of Acetic Acid/Sodium Acetate Solution

[gsingh2011]

The problem is:
Calculate the pH of a solution created by mixing 200.0 mL of .400 M acetic acid and 200.0 mL of 1.00 M sodium acetate.

I got 2.02 for the pH, but according to other people in my class that's the wrong answer. Could someone explain how to do this? I used the Initial, Change, Equilibrium tables, if anyone knows how to do that..

 

[sjb-2812]

Can you go through your entire working? Perhaps look into the Henderson Hasselbalch equation or similar?