What is the connection of Chords and Scales?

[williamraym]

Is there a connection between piano chords and piano scales? Is it like when the scale is change does the formation of the chord also change?

[m1469]

Is there a connection between piano chords and piano scales?

Yes!  Chords are just scales with holes in it.  Any chord can function in more than one scale because some scales share some of the same tones as each other.  For example, in the C Major scale, you can build a C Major chord by using only the Tonic (1), Mediant (3), and Dominant (5) scale degrees, and that chord would serve the purpose of the I chord in the scale of C Major.  

If you move one degree in the circle of 5ths in either direction, you will find a new scale that shares almost exactly the same notes as the C Major scale except for one - to the right of C Major is G Major, which has the same notes as C Major except for F#, to the left of C Major is F Major, which has the same notes as C Major except for Bb.  

You can build a C Major chord in both of those scales, as well, but since C isn't the starting pitch of the scale, a C Major chord will serve a different function within it.  In F Major, the C chord is V, in G Major the C chord is IV.

[lloyd_cdb]

I'm not completely sure what you're asking, but hopefully this answers your question.  I'll go over Major Scales and chords:

A major scale is constructed by taking set intervals starting on whichever key you wish.  The interval in steps is:

root - whole - whole - half - whole - whole - whole - half(back to the root)
--C-----D------ E------F ---- G ----- A ----- B----- C

I put a C major scale underneath for reference.

In the C Major scale, a C Major chord is constructed by the root note (C) - 2 whole steps (E) - 1 whole+1 half (G).  This construction stands for any Major scale you can make.  Minor chords are constructed the opposite way: root - 1.5 - 2

Constructing chords in a specific Major scale (we'll stick with C here), only using the notes provided in the scale, there is only one basic chord you can make for any root note.  Here is the scale again for reference:

root - whole - whole - half - whole - whole - whole - half(back to the root)
--C-----D---- E -------F ---- G ----- A ----- B----- C
--I----- ii --- iii ------ IV ---- V ----- vi ---- vii* --- I

What I've added below the scale is the number position of the root note and the type of chord you can construct.  If you choose the root note with the upper case roman numerals (I,IV,V) you can make a major chord.  If you choose the root note with lower case (ii, iii, vi) you can make a minor chord (again, this is only using the notes provide in the scale).  The last one (vii*) is the special case, where the chord is constructed using: root - 1.5 - 1.5.  This is called a diminished chord. I gave you the example of a Major chord in the previous section, so here is an example of a Minor chord: Root (D) - 1.5 (F) - 2 (A)

I hope this answers your question without being overly complex.