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 octane, C8H18, is 1.308×103 kcal/mol. How much energy is released during the complete combustion of 354 grams of octane ?

Answer 1

4054 kcal of heat is released during complete combustion of 354 g of octane.

Step-by-step explanation:

Heat of combustion of 1 mol of octane is
`1.308* 10^(3)` kcal

Molar mass of octane = 114.23 g/mol

We know, no. of moles = (mass)/(molar mass)

So,
`1.308* 10^(3)` kcal of heat is released during complete combustion of 114.23 g of octane.

So, amount of heat is released during complete combustion of 354 g of octane =
`((1.308* 10^(3))/(114.23))* 354` kcal = 4054 kcal

Hence 4054 kcal of heat is released during complete combustion of 354 g of octane.