Dora, those are great ideas

, but you will need to cut down on your description of each piece since you have only 400 words or so to do all 5 pieces. So 80 words per piece--My suggestions would be:
Really short intro--for example, "Beethoven, in a mood of high tragedy, wrote the 'Sonata Pathetique' in the year 1798." (something like that to give a piece of info and the idea that the sonata is tragic in mood)
You can combine style, "What is it" and dynamics in one statement. "A
sonata is a piece classically composed of three movements--often two fast /high-energy ones surrounding a slower, more tranquil interlude. Beethoven followed the three-movement structure here, but ventured from the strict Classical style into the Romantic by starting with a slow, dramatic introduction; it is only after this proclamation of tragedy, that he launches into the traditional
allegro.
(That was about 60 words--You get the picture!)
Have fun!--and by the way, your English is great!
Teresa