Sure, but first ask yourself - Do I want to play that disc in a CD player that can NOT play it natively?
If you don't, then really if your source material is an MP3 file, then converting it over to FLAC isn't going to make the sound quality any better - it's already at a lower Q format than FLAC so just turning it into a FLAC won't raise the actual sound quality. You can just either keep it on the HD or sure.. burn it "as is" onto a CD, as a lot of CD and DVD players out there can still play compressed "files" such as MP3 natively - and you'll have a lot more than 80 mins of music on a single CD.
But if you do, then you can use CD mastering/burning software such as Nero. When you first start Nero (just an example.), it will ask you what kind of CD you want to burn - if you choose "Audio" then it's smart enough to where when you drop the MP3 file onto the CD layout screen, it will convert it to the correct format prior to the actual "write".
If you don't have software like Nero, then I think you can still use what comes with Windows (nowadays.. but I never use that). The key I believe is to make sure the MP3 file is converted to a "wav" (wave) file that is spec'd at 44.1Khz sampling rate and 16 bit depth. And.. there's software for that too. Just search for it.