I would like to make a file with a track that is a specific time frame (5:04 seconds) and no more, no less. I do not have any audio and in fact I just want a soundless time keeper in my playlist. How do I create such a file?
Open Audacity and before opening any file: Generate → Silence.
Then, File → Export in your desired format.
Note this may not be absolute silence when you export because Audacity may add very quiet dither noise - see http://manual.audacityteam.org/o/man/faq_playback.html#dither .