Fermentation of starch and sugar crops yields 5% to 20% molar volume of ethanol in water, which is too wet to burn. distillation of this mixture to remove water produces a mixture of 95% ethanol and 5% water, the azeotrope of the mixture, which is called hydrous ethanol. detydration to anhydrous ethanol, which is 99.7% pure ethanol and is the standard for blending with gasoline in the u. s., requires additional processing and costs. in brazil most vehicles are flex fuel vehicles of a different design that flex fuel vehicles in the u. s., in that they can burn straight hydrous ethanol (no gasoline) as well as any mixtures of gasoline and hydrous ethanol 1a) calculate the enthalpy change when oxidizing (burning) pure ethanol in air if the initial temperature is at 25c and the exhaust temperatures is 6ook. 1b) recalculate the enthalpy change for a hydrous ethanol mixture of 95% ethanol and 5% water. assume the 95: 5 mixture of ethanol and water is on a mass basis.