How could you figure out what key a piece of music is in?

Question

I heard that its usually the first chord played in a song but what if thats not true. How could you tell.

Answer 1

on the staff after the f or g clef there should be b or # the b are flats and the # are sharps depending on how many b or # there are determines the key

there on no b or # in c major  so there woulndt be any b or #'s

Answer 2

Just remember the key of a song is not limited to 1.  Many vernacular songs and much more cultivated musics contain more than one key.  The key to finding the key is looking at cadences.  Which opens up many more discussions, but look for cadences in pop songs of:

V (5) to I (1)

e.g. Chords G to C

or

IV to I

e.g. F to C

good luck!

Answer 3

while in most cases it is true that a one chord is played as the first note, it is not always true!  to really tell what key the piece is in, a good thing to look at is the key signature.  look at how many accidentals are in the key signature (flats or sharps) and depending on that find the key.