We present results from an investigation of the oxidative conversion of ethanol into acetaldehyde on Au(111) employing temperature-programmed desorption (TPD) and molecular beam reactive scattering (MBRS). Results from isotopic experiments show that ethanol initially undergoes O-H bond cleavage (producing ethoxide) followed by selective beta-(CH)-H-. bond (a to the oxygen) activation to form acetaldehyde and water on atomic oxygen precovered Au(111). Our study on bulk gold with atomic oxygen provides insight into the mechanistic details for high-surface-area gold-based catalysts and their application in the oxidation chemistry of alcohols employing molecular oxygen or air.