This Mazurka by Chopin is in simple ternary form. The A section of this piece opens up with 4 measures of Bb major ending on a PAC. A longer phrase modulates, ending 6 measures later on an IAC, making this an asymmetric progressive period. 4 measures brings us to another PAC cadence in G minor, with a short cadential extension marking the end of the first section. Notice sF, lots of pedal markings, and grace notes litter this section.
The B section starts similar to A section, but quickly contrasts to the previous material. The first four measures are nothing out of the ordinary, ending on an IAC in the original key of Bb. The next 12 measures of this section are very chromatic. So much so that it makes the key very ambiguous. Chopin adds new articulations, rhythms (especially triplet patterns), register changes, and dynamic contrasts to really alter it from the A section. The first and last four measures display an ostinato pattern in the right hand of eight eight triplet quarter. I would argue that this is a phrase group ending on a PAC.
There is a smalle sotto voce part right after the B section that serves as an interlude between sections. With it's monophonic melody, Chopin brings us back to a literal recapitulation. The piece ends on a drawn out cadential extension into a g minor PAC.