What are the key differences changes within the style, form and musical techniques used in piano music between the classical and romantic periods?

There were several key differences between the Classical and romantic era’s in relation to piano music. In the progression of the two era’s there was a marked change in the stylistic elements of the music itself. Whilst the classical period had an emphasis towards elegance and balance in its music, the romantic period focused upon the use of song-like melodies and newer harmonic elements to be designed to feel much more personal and emotive to the listener or player. This change of style also complemented the changes of form between the two periods. With music for the piano, the most important used design of Classical music was the sonata form which took precedence over all other forms of music for the period. This was greatly expanded within the romantic period and included many new forms of music writing stylistically. These included: Ballade, Nocturne, Intermezzo, Waltz, Polonaise, Impromptu, Romance, Rhapsody, & Song without words (or prelude). The musical techniques used were also markedly different between these two periods. Although both periods used the melody and accompaniment style of writing predominantly, Classical music was somewhat constricted in the use of different key signatures, melodies, rhythms and dynamics in comparison to the Romantic period, which also favoured the use of expanding outside of the usual notes of the chosen key (chromaticism) and key changes (modulations - moving towards keys other than the usual dominant or relative minor) within a piece.