Would gold react with chlorine in considering Au + HCl? And how would I be able to determine this without asking you?

Gold won't react with HCl -- at least not if you simply mix the two. Normally, to dissolve gold, you need chloride (to complex with the gold), an oxidizing agent (nitric acid is the most common) to oxidize the gold. A mixture of hydrochloric acid and nitric acid is often called aqua regia (royal water).

http://en.wikipedia.org/wiki/Aqua_regia

If you bubbled chlorine gas into a mixture of hydrochloric acid and gold, you might be able to get gold to dissolve. I've never tried that.