The enthalpy of combustion of ethanol is −1371 kJ mol−1 . The density of ethanol is 0.789 g cm−3 . Calculate the heat energy released in kJ when 1 dm3 of ethanol is burned.
1 dm3 of ethanol is equal to 1000 cm3, so the mass of ethanol used is =density x volume = 0.789 g cm-3 x 1000 cm3 = 789gMolar mass of ethanol = (2x12)+(6x1) +(1x16)= 46 g mol-1Moles of ethanol = mass/molar mass = 789/46=17.15 molesHeat Energy produced = ethalpy x moles = 1371 kJ mol-1 x 17.15 = 23516 kJ
SL
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