Answer to Question 1
The Blues Chord Progression is:
Tonic (I chord, built on the first scale degree) for measures one through four
Subdominant (IV chord, built on the fourth scale degree) for measures five through six
Return to tonic (I chord) for measures seven through eight
Dominant (V chord, built on the fifth scale degree) measure nine
Subdominant (IV chord) measure ten
Return to tonic (I chord) measure eleven
Dominant (V chord) in measure twelve if the blues is going on to another stanza or to the I chord if the song is ending.
Answer to Question 2
Textually, a blues is a series of rhymed three-line or quatrain-refrain stanzas, each sung more or less to the same tune. Blues tunes usually consist of twelve measure (bar) stanzas, use a blues scale (variable 3, 5, or 7 scale degrees that may be lowered at the discretion of the performer) and blues are rhythmically complex, at times using syncopation (misplaced accents which fall on normally unaccented beats or in between the regular beats of the music) and/or polyrhythms/meters (more than one rhythm or meter at the same time; for example, the singer and his/her accompaniment are often in contrasting rhythms and/or meters). The singer often has a raspy, improvised vocal quality.