Expressionist music has a distinct sound:
It is intensely emotional.
Has angular melodies.
Has lots of dissonance, chords with clashing notes.
Has lots of atonal harmonies, chords using notes from the chromatic scale.
Has contrasting dynamics.
Doesn’t have many cadences, repetition or sequences.
It never sticks with any one musical idea for long.
Schoenberg had done away with the conventions of using major or minor keys he needed some form of structure, he called his form of structure serialism. Serialism meaning that it could be a set order of volume changes or a particular set of notes. He also in his first go at serialism Schoenberg found a ordering of the notes. This was named the 12 note system.
The piece of the Peripetie was wrote originally for a large orchestra with all sections. The instrumentation changes throughout rapidly creating lots of contrasts in timbres, which means the character or quality of a musical sound or voice as distinct from its pitch and intensity. Usually a lot of people play this nearly up to 90 people in fact.
The melody is made up of many short fragmented motifs, broken up bits of a short tune that sticks out, combined in different ways to create interest. Melodies are usually disjunct, which is a type of melodic motion; proceeding by leaps from one scale degree to the next by intervals, and sound angular.
The meter of the piece changes continually between 2/4, 3/4, and 4/4. The tempo marking is sehr rasch meaning that the piece is meant to be played very fast. The rhythms are