Ethylene oxide (C2H40) is a high volume chemical intermediate that is used to produce glycol and polyethylene glycol. Ethylene oxide is produced by the partial oxidation of ethylene (C2H4) using a solid catalyst in a fixed bed reactor: 2C2H4 + 02 2C2H40 (1) Unfortunately, a portion of the ethylene reacts completely to CO2 and H2O: C2H4 + 302 2CO2 + 2H2O (2) The product gas leaving a fixed bed ethylene oxide reactor has the following water free composition: 20.5% C2H40, 72.7 % N2, 2.3 % O2, and 4.5% CO2. Determine the percent excess air used in the reactor, based on the desired reaction (1) and the mass of ethylene feed (in lbs/hr) required to produce 100,000 tons/year of ethylene oxide