Posted: Sat Jan 13, 2018 9:25 pm
Can someone please explain this problem to me? I'm super confused! Are we just supposed to use enthalpies of formation and if so what do we do next?
Posted: Sat Jan 13, 2018 11:14 pm
Yes, you use enthalpies of formation to find the enthalpy of reaction for the reaction.
28(-393.51kJ/mol)+10(-241.82kJ/mol)-4(067kJ/mol)=-13168kJ/mol (the energy released per mole of reaction)
Since it is asking "per mole," 1/4 of the energy (3292kJ/mol) will be released per mole of TNT consumed.
In order to get the energy density in "kJ/L," you need to take 3292kJ/mol and divide it by the mass of one mole of TNT (227.14 g/mol) and then multiply it by the density of TNT (1.65 g/cm^3) and then convert cm^3 to L (10^3cm^3/L).
The answer should be 23.9x10^3kJ/L