Ethanol, C 2 H 6 O, is most often blended with gasoline - usually as a 10 percen

Question

Ethanol, C2H6O, is most often blended with gasoline - usually as a 10 percent mix - to create a fuel called gasohol. Ethanol is a renewable resource and ethanol-blended fuels, like gasohol, appear to burn more efficiently in combustion engines. The heat of combustion of ethanol is 326.7 kcal/mol. The heat of combustion of 2-methylheptane, C8H18, is 1.306×103 kcal/mol. How much energy is released during the complete combustion of 482 grams of 2-methylheptane?

Assuming the same efficiency, would 482 grams of ethanol provide more, less, or the same amount of energy as 482 grams of 2-methylheptane?

Explanation / Answer

heat of combustion of ethanol is 326.7 kcal/mol

heat of combustion of 2-methylheptane, C8H18, is 1.306×103 kcal/mol

no of mol of C8H18 = 482/114 = 4.23 mol

energy released, C8H18 = 4.23*1306 = 5524.4 kcal

no of mol of ethanol = 482/46 = 10.5 mol

energy released,CH3CH2OH = 10.5*326.7 = 3430.35 Kcal

so that, amount of energy by 2-methylheptane is higher than ethanol.

Related Questions

Navigate

• Browse (All)
• Browse E
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.