While ethanol is produced naturally by fermentation, e. g. in beer- and wine-making, industrially it is synthesized by reacting ethylene with water vapor at elevated temperatures. A chemical engineer studying this reaction fills a tank with of ethylene gas and of water vapor. When the mixture has come to equilibrium he determines that it contains of ethylene gas and of water vapor.

The engineer then adds another of ethylene, and allows the mixture to come to equilibrium again. Calculate the moles of ethanol after equilibrium is reached the second time. Round your answer to significant digits.