To calculate the mass of ethanol required to produce 411 kJ of thermal energy, we can use the given enthalpy change of the combustion reaction and set up a proportion. The enthalpy change for the combustion of ethanol is -1367 kJ, which means 1367 kJ of thermal energy is released. Using the given proportion:
Energy Released (kJ) from known amount of ethanol/Mass of ethanol (g)
=
Energy Required (kJ)
Mass of ethanol required (g)
Mass of ethanol (g)
Energy Released (kJ) from known amount of ethanol
=
Mass of ethanol required (g)
Energy Required (kJ)
We can solve for the mass of ethanol required using the given information:
Calculating this expression gives the mass of ethanol required to produce 411 kJ of thermal energy.
The mass of ethanol required to produce 411 kJ of thermal energy is approximately 0.301 kg.
The molecular weight of ethanol is 46.07 g/mol, so the mass required would be 16.95 g for 500 kJ of heat
