Not sure exactly what you mean, but I suppose you're getting confused because of how the phrase is pronounced when spoken fast.
For a native speaker, "Thank Q" and "Thank you" are pronounced the same way. This is because the "k" sound and the "you" (i.e 'u' ) sound make a "kyuu" sound, which is also how Q is pronounced. The only way you can possibly make a distinction is if you pause in the middle.
I can't think of any good examples, but some obvious ones would be phrases like "track you." Don't know where you'd use it, but still.