The fifth sonata in the set of Kv301-306 has again two movements but has a larger second movement than all the previous sonatas, this because it is a 'theme and variation'. It is not sure if it was written before or after the E-minor Kv.304 sonata.
The first movement has the same type of opening as the Kv.296 and Kv.302 with a Forte broken chord opening and a complementing Piano segment. It is a very happy and uplifting piece of music. Both instruments show a clear virtuosity, especially with the accompaniment and the quick changes of the themes. The development section has more modulations than before and is more extended. In the recapitulation, there are slight variations in the piano part with octaves in the second theme.
The second movement, as said in the introduction, is a Theme and variation. The first variation is for solo piano and this is one of the reasons why this sonata is sometimes called 'a piano concerto'. Though it is written in a calm Andante, it is full of virtuosity and gives a happy feeling as well to the listener. Especially in the second and the fourth variation the violin has a major part with an accompanying piano-part. The minor variation, before the last (coda) part, is written melodically in both hands with an octave difference that brings a more intertwined impression compared to the other variations. The Allegro coda which starts with the piano introducing the theme has the feeling of the Menuet dance that Mozart wrote as well in the second movement of the Kv.303 and Kv.304 sonatas.