One of the most useful collections of thermodynamic information is the larger number of standard heats of formation of chemical compounds. From these data and Hess’s law, the standard heats of reaction of numerous chemical processes can be calculated. The experimental and computational determination of the heat of formation of a compound of a compound is therefore an important contribution to thermodynamics and the molecular sciences. One common way to determine the standard heat of formation of a pure substance is from its heat of combustion (and Hess’s Law) using an adiabatic constant volume oxygen ‘bomb’ calorimeter. I have created a separate blog post with details of using a Parr ‘Bomb’ calorimeter.
This blog post is to provide some useful links and general information about ‘bomb’ calorimetry. Lets start with an old but VERY useful simulation website. – https://web.mst.edu/~gbert/cal/bomb/Acal.html
I would love to see this simulation be updated for modern HTML5 similar to PHET. In my opinion, it is very very useful to simulate bomb calorimetry before actually doing it in person.
From simulations and even just looking about basic information about bomb calorimetry instrumentation, a student can PREDICT how much of a temperature change is expected BEFORE actually doing the experiment.
I also highly recommend doing computational chemistry to calculate heats of reaction (i.e., combustion, formation) BEFORE doing any experiments. You can do 10’s or 100’s of computer ‘experiments’ in much less time than you can physical experiments. Computational chemistry like ab initio electronic structure computation has become an invaluable resource for physical chemists wanting to make the connection between theory and experiment. So, below are some recommended resources for some computational chemistry that are useful when considering computational thermochemistry.
- MolCalc is a web interface that allows chemist to build small molecules and estimate molecular properties such as
- molecular structure
- heats of formation and other thermodynamic properties
- vibrational frequencies and vibrational modes
- molecular orbitals and orbital energies
- Gaussian and GaussView are well-established computational chemistry software packages.
- Other Ab Initio computational chemistry packages that I find useful
- Computational Heat of Combustion and Heat of Formation – Prof. Yarger YouTube Video Example.
- Example of Thermochemistry Calculation in Gaussian 09 (or Gaussian 16)
- Example publication – Calorimetric and Computational Study of Enthalpy of Formation of Diperoxide of Cyclohexanone.
- For GUIs, Molecular Viewing, Toolsets, etc… I suggest the following
Okay, you have simulated heat of combustion bomb calorimetry and you have done some computational chemistry to look at combustion and/or formation reactions. I have a blog on the specifics of using a Parr Bomb Calorimeter and provide a few more useful links below.
- Video Examples
- Standard States for Bomb Calorimetry – NIST
- Information and Data taken from Bomb Calorimetry experiments done at ASU in CHM 343 and CHM 349 (Physical Chemistry Laboratory). This data is being shared through a google account – BioPchem@gmail.com and the associated Google Drive. The public sharing link is provided below: