## Problem 8.51

Fenared Ortiz 3K
Posts: 37
Joined: Wed Nov 16, 2016 3:03 am

### Problem 8.51

The enthalpy of formation of trinitrotoluene (TNT)
is 67 kJ·mol 1, and the density of TNT is 1.65 g·cm 3. In principle, it could be used as a rocket fuel, with the gases resulting from its decomposition streaming out of the rocket to give the required thrust. In practice, of course, it would be extremely dangerous as a fuel because it is sensitive to shock. Explore its potential as a rocket fuel by calculating its enthalpy density (enthalpy released per liter) for the reaction

Im confused on what it means to find/calculate the enthalpy density. What equation(s) should I use, and should i be converting anything?

Cooper1C
Posts: 50
Joined: Fri Sep 29, 2017 7:07 am

### Re: Problem 8.51

You use the enthalpies of formation to calculate delta H, then you have to convert kJ/mol TNT to kJ/L, which is why you need to know the density of TNT.

torieoishi1A
Posts: 32
Joined: Sat Jul 22, 2017 3:00 am

### Re: Problem 8.51

When using the enthalpy of formation equation, you should get -13168 kJ/mol. This is the amount of energy released per mole of reaction. In order to get the amount of energy released per mole of TNT consumed, you divide the total amount of energy released (-13158kJ/mol) by 4 (from looking at the balanced chemical equation)...releasing 3292kJ/mol of TNT consumed. Then to get energy density in kJ/L, you divide the amount of energy witht he mass of one mole of TNT and multiply it by the density of TNT. The answer should be 23.9 x 10^3 kJ/L