Five liters of liquid n-hexane and 4 liters of liquid n-heptanes are mixed and burned with 4000 gram- moles of air. Not all of the hydrocarbons are burned in the furnace, and both CO and CO2 are formed. If it is possible to do so without additional information, calculate the percent excess air supplied to the furnace: if more information is needed, state what it is and outline the calculation of the percent excess air.