Hess Cycle: Enthalpy of formation of Ethanol - Long method

Early experimental effort at providing home tuition in chemistry via YouTube. Please visit www.chemy.info for later efforts using a better video camera. To get an enthalpy of formation from 3 enthalpies of combustion. While the short method is usually best, it assumes that the oxygen atoms balance. Here, on one occasion, an effort is made to show that everything does tally up. This method is like algebra - you add, multiply and rearrange chemical equations! I have provided a help sheet here: http://www.geocities.com/loretochemistry/YouTube/support/Hess_Cycle_eths.htm Answer should be displayed like this: Enthalpy = (-786)+ (-858) + (1371) = -273 kJ/mol The marker can quickly see where any mistake has been made - thus awarding some marks for an incorrect final answer! Apologies for the poor quality of the video and the very basic form of presentation used. If it's a topic that's causing you difficulties, perhaps it will be of some help. Rgds FS