Prelude in B minor is from Frederic Chopin's 24 Preludes, which covers all major and minor keys. It is believed that this prelude, along with others, were played at his funeral. Nicknames given to this prelude after Chopin's death include "Homesickness" and "Tolling Bells."
This piece can help students learn to play in a legato style, as well as learning to play expressively.
Francisco Tarrega (1852-1909) was a Spanish composer and classical guitarist regarded by many as "the father of the classical guitar." Adelita is a mazurka originally composed for guitar by Tarrega. The mazurka originated in Poland and was popularized by Frederic Chopin.
The tempo is indicated as Lento, but seems to work better at a faster tempo. The audio file here is at 80 bpm. However, this piece should not be performed metronomically, but rather with a more rubato style.