Textbook 4D.9 [ENDORSED]

[Lynne Zhao 2B]

How do we find the enthalpy density of the reaction? Can we combine enthalpy densities with Hess's law?

[Chem_Mod]

As stated in the question, enthalpy density is the enthalpy change per liter for the reaction.

Use standard enthalpies of formation as I did in class to calculate the standard reaction enthalpy per mole TNT.

Then figure out how many moles of TNT in 1L using the given density of TNT.

Then the multiple moles of TNT per L by the standard reaction enthalpy per mole TNT:

mol/L x kJ/mol = kJ/L

[Kaitlin Eblen 1I]

I solved with this problem by first finding the standard reaction enthalpy per mole of TNT (use Appendix 2A for the standard enthalpy of formation values for CO2 and H2O gas). Now that you have found the enthalpy, you need to find the volume of the TNT used in the reaction. First, convert the density to g/L. You can now use the density of TNT to find the volume in Liters.



Then, divide the standard enthalpy of reaction (in kJ) by the volume (in liters) to find the enthalpy density! Basically, calculating how much energy is released per unit volume.

[Anna Turk 1D]

How did you find the standard reaction enthalpy for TNT?

[Chem_Mod]

How did you find the standard reaction enthalpy for TNT?

Use standard enthalpies of formation as I did in class to calculate the standard reaction enthalpy per mole TNT.