The amount of energy released during the combustion of 0.018 gal of ethanol that has a density of 0.78 g/mL is _____ kJ. (Given ΔH^o_c_omb of ethanol = -1371 kJ/mol).

Question

Quizplus · Accepted Answer

First, we need to convert the volume of ethanol given in gallons to milliliters (mL):

0.018 gal x 3785 mL/gal = 68.13 mL

Next, we can calculate the mass of ethanol using its density:

68.13 mL x 0.78 g/mL = 53.14 g

We can then use the molar mass of ethanol (46.07 g/mol) to calculate the number of moles:

53.14 g / 46.07 g/mol = 1.152 mol

Finally, we can use the given enthalpy change of combustion (-1371 kJ/mol) to calculate the energy released:

-1371 kJ/mol x 1.152 mol = -1575.79 kJ

Rounding to the appropriate number of significant figures, we get -1.6 × 10^3 kJ or -1600 kJ. Therefore, the best choice is E.

The Amount of Energy Released During the Combustion of 0