By songs, you mean pieces. Also, how can you assume it's by Mozart? That's very dubious. It can also be Bach, seeing as he did compose the "Well-Tempered Clavier", or any other composer that happened to work on the harpsichord.
Please, don't ask us for this in such an unprecise manner. If you could upload a sample of it, I'm sure I could at least recognise it from somewhere.