Hydrogen and methanol have both been proposed as a...

Question

Hydrogen and methanol have both been proposed as alternatives to hydrocarbon fuels. To compare the energy of these fuels to that of octane (C8H18), calculate the energy released per kilogram of octane.

Jules Bruno · Accepted Answer

The combustion of hydrogen is:H2(g) + ½ O2(g) → H2O(l)The standard enthalpy of formation(∆H°f) of H2O(l) is -285.8 kJ/mol. This value can be found in books or reliable internet source. The negative value indicates that the reaction is exothermic.Converting ∆H°f into kJ per kilogram[readmore]For methanol (CH3OH), the enthalpy of the reaction can be calculated from the enthalpy of formation of the reactants and products:2 CH3OH(l) + 3 O2(g) → 2 CO2(g) + 4 H2O(l)∆H°f CH3OH(l) = -238.6 kJ/mol∆H°f O2(g) = 0 (in its natural state)∆H°f CO2(g) = -393.5 kJ/mol∆H°f H2O(l) = -285.8 kJ/molConverting ∆H°f into kJ per kilogramThe enthalpy of octane can be calculated in a similar manner2 C8H18 + 25 O2 → 16 CO2 +18 H2O∆H°f C8H18(l) = -249.79 kJ/mol∆H°f O2(g) = 0 (in its natural state)∆H°f CO2(g) = -393.5 kJ/mol∆H°f H2O(l) = -285.8 kJ/molConverting ∆H°f into kJ per kilogramBased on the calculations, methanol (-2.22x104 kJ/mol) released the smallest amount of energy followed by octane (-4.79x104 kJ/mol). Hydrogen released the highest amount of energy (-1.42x105 kJ/mol).

Problem: Hydrogen and methanol have both been proposed as alternatives to hydrocarbon fuels. To compare the energy of these fuels to that of octane (C8H18), calculate the energy released per kilogram of octane.

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Problem Details

Problem: Hydrogen and methanol have both been proposed as alternatives to hydrocarbon fuels. To compare the energy of these fuels to that of octane (C8H18), calculate the energy released per kilogram of octane.

FREE Expert Solution

Problem Details

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