You don't need to know many guitar scales ... Unlike chords, scales are played one note at a time. You should be able to see that the C major pentatonic scale uses all the notes from a C chord ...

In theory, the name of a chord should describe its content, especially if it differs from the root-3rd-5th of a standard major chord. In guitar ... position. There is no b7 th, just the root-3rd ...