Sonata form...woo! So here we go. We begin with group 1, or the first tonal area. This section appears to be an asymmetrical binary form. The group ends on a PAC and leads into a brief transitional section into the second tonal area. In group 2 we find ourselves in, surprise, the dominant key. This section quickly ends on a HC in our original key, sending us back to the begining for a repeat of the Exposition. The exposition ends on a PAC in the dominant key 4 mins after beginning.
In the developmental section of this sonata we hear material from the first tonal area molded into something different. Mozart plays with several keys, eventually retransitioning us back into the recapitulation with a half cadence in our original key.
But alas, we are in our sub-dominant key for the beginning of the recapitulation. With a little Mozart magic we transition ourselves back to the key of Bb, and end group 2 and the sonata with a powerful PAC. Whew.